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Use system-wide LevelDB instead of bundled one

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This commit is contained in:
Sfan5 2013-09-09 22:46:18 +02:00
parent 1f3402e7a1
commit 3725179736
132 changed files with 12 additions and 25810 deletions
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21
src/CMakeLists.txt
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@ -174,9 +174,6 @@ find_package(Sqlite3 REQUIRED)
find_package(Json REQUIRED)
find_package(OpenGLES2)
SET(LEVELDB_INCLUDE_DIR ${PROJECT_SOURCE_DIR}/leveldb/include)
SET(LEVELDB_LIBRARY leveldb)
if(USE_FREETYPE)
find_package(Freetype REQUIRED)
set(CGUITTFONT_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/cguittfont")
@ -209,9 +206,18 @@ set(USE_LEVELDB 0)
OPTION(ENABLE_LEVELDB "Enable LevelDB backend")
if(ENABLE_LEVELDB)
set(USE_LEVELDB 1)
message(STATUS "LevelDB backend enabled")
include_directories(${LEVELDB_INCLUDE_DIR})
find_library(LEVELDB_LIBRARY leveldb)
find_path(LEVELDB_INCLUDE_DIR db.h PATH_SUFFIXES leveldb)
message (STATUS "LevelDB library: ${LEVELDB_LIBRARY}")
message (STATUS "LevelDB headers: ${LEVELDB_INCLUDE_DIR}")
if(LEVELDB_LIBRARY AND LEVELDB_INCLUDE_DIR)
set(USE_LEVELDB 1)
message(STATUS "LevelDB backend enabled")
include_directories(${LEVELDB_INCLUDE_DIR})
else(LEVELDB_LIBRARY AND LEVELDB_INCLUDE_DIR)
set(USE_LEVELDB 0)
message(STATUS "LevelDB not found!")
endif(LEVELDB_LIBRARY AND LEVELDB_INCLUDE_DIR)
endif(ENABLE_LEVELDB)
configure_file(
@ -635,7 +641,4 @@ else (JSON_FOUND)
add_subdirectory(json)
endif (JSON_FOUND)
if (USE_LEVELDB)
add_subdirectory(leveldb)
endif (USE_LEVELDB)
#end

8
src/leveldb/.gitignore vendored
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@ -1,8 +0,0 @@
build_config.mk
*.a
*.o
*.dylib*
*.so
*.so.*
*_test
db_bench

8
src/leveldb/AUTHORS
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@ -1,8 +0,0 @@
# Names should be added to this file like so:
# Name or Organization <email address>
Google Inc.
# Initial version authors:
Jeffrey Dean <jeff@google.com>
Sanjay Ghemawat <sanjay@google.com>

178
src/leveldb/CMakeLists.txt
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@ -1,178 +0,0 @@
set(CMAKE_LEGACY_CYGWIN_WIN32 0)
cmake_minimum_required(VERSION 2.8)
PROJECT(leveldb)
# version
set(LIB_MAJOR 0)
set(LIB_MINOR 0)
set(LIB_RELEASE 1)
set(CMAKE_INSTALL_SO_NO_EXE "0")
include(CheckIncludeFile)
include_directories(${CMAKE_CURRENT_SOURCE_DIR} include)
# STATIC/DYNAMIC LIBRARY INCLUSION
if(MINGW OR WIN32)
OPTION(STATIC "build a static binaries. This is mainly intended for the win32-package and the MACOSX-bundle." ON )
else(MINGW OR WIN32)
OPTION(STATIC "build a static binaries. This is mainly intended for the win32-package and the MACOSX-bundle." OFF )
endif()
# OS detection
if(WIN32)
message(FATAL_ERROR "LevelDB currently doesn't support Windows")
add_definitions(-DLEVELDB_PLATFORM_WINDOWS -DOS_WIN -DWIN32_LEAN_AND_MEAN)
if(MINGW)
add_definitions(-DMINGW)
endif()
if(MSVC)
add_definitions(-DCOMPILER_MSVC)
endif()
set(PORT_SRCS port/port_win.cc util/env_boost.cc)
set(CIF_SRCS)
elseif(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
add_definitions(-DLEVELDB_PLATFORM_POSIX -DOS_FREEBSD)
set(PORT_SRCS port/port_posix.cc util/env_posix.cc)
set(CIF_SRCS db/c.cc)
elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
add_definitions(-DLEVELDB_PLATFORM_POSIX -DOS_LINUX)
# link pthread
set(PORT_SRCS port/port_posix.cc util/env_posix.cc)
set(CIF_SRCS db/c.cc)
elseif(CYGWIN)
add_definitions(-DLEVELDB_PLATFORM_POSIX -DOS_LINUX)
set(PORT_SRCS port/port_posix.cc util/env_posix.cc)
set(CIF_SRCS db/c.cc)
elseif(APPLE)
add_definitions(-DLEVELDB_PLATFORM_POSIX -DOS_MACOSX)
set(PORT_SRCS port/port_posix.cc util/env_posix.cc)
set(CIF_SRCS db/c.cc)
endif()
# FIXME: check cstdatomic here..
set(SRCS
db/builder.cc
db/db_impl.cc
db/db_iter.cc
db/filename.cc
db/dbformat.cc
db/log_reader.cc
db/log_writer.cc
db/memtable.cc
db/repair.cc
db/table_cache.cc
db/version_edit.cc
db/version_set.cc
db/write_batch.cc
table/block.cc
table/block_builder.cc
table/filter_block.cc
table/format.cc
table/iterator.cc
table/merger.cc
table/table.cc
table/table_builder.cc
table/two_level_iterator.cc
util/env.cc
util/arena.cc
util/bloom.cc
util/cache.cc
util/coding.cc
util/comparator.cc
util/crc32c.cc
util/filter_policy.cc
util/hash.cc
util/histogram.cc
util/logging.cc
util/options.cc
util/status.cc
${PORT_SRCS}
${CIF_SRCS}
)
set(HDRS
include/leveldb/c.h
include/leveldb/cache.h
include/leveldb/comparator.h
include/leveldb/db.h
include/leveldb/env.h
include/leveldb/iterator.h
include/leveldb/options.h
include/leveldb/slice.h
include/leveldb/status.h
include/leveldb/table.h
include/leveldb/table_builder.h
include/leveldb/write_batch.h)
set(TESTHARNESS_SRCS
util/testutil.cc
util/testharness.cc)
include_directories(${CMAKE_CURRENT_BINARY_DIR})
if(BUILDSTATIC)
add_library(leveldb STATIC ${SRCS})
else(BUILDSTATIC)
add_library(leveldb SHARED ${SRCS})
endif()
set(_soversion ${LIB_MAJOR}.${LIB_MINOR}.${LIB_RELEASE})
set_target_properties(leveldb PROPERTIES SOVERSION ${LIB_MAJOR} VERSION ${_soversion})
target_link_libraries(leveldb pthread)
SET (LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR}/lib)
IF(MINGW)
set_property(TARGET leveldb PROPERTY LINK_SEARCH_END_STATIC ON)
set_target_properties(leveldb PROPERTIES LINK_FLAGS "-static-libgcc")
ENDIF()
INSTALL(FILES ${HDRS} DESTINATION ${CMAKE_INSTALL_PREFIX}/include/leveldb)
if(MINGW OR WIN32)
INSTALL(TARGETS leveldb DESTINATION ${CMAKE_INSTALL_PREFIX}/lib)
else(MINGW OR wIN32)
INSTALL(TARGETS leveldb LIBRARY DESTINATION ${CMAKE_INSTALL_PREFIX}/lib)
endif()
if(TESTDB)
ENABLE_TESTING()
# TESTS
add_library(leveldb-testharness STATIC ${TESTHARNESS_SRCS})
macro(leveldb_test ${nam})
endmacro()
macro(leveldb_tests)
foreach(t ${ARGN})
get_filename_component(_tname ${t} NAME_WE)
add_executable(${_tname} ${t})
target_link_libraries(${_tname}
leveldb-testharness
leveldb
pthread
)
endforeach()
endmacro()
leveldb_tests(
db/db_bench.cc
util/arena_test.cc
db/c_test.c
util/cache_test.cc
util/coding_test.cc
db/corruption_test.cc
util/crc32c_test.cc
db/db_test.cc
db/dbformat_test.cc
util/env_test.cc
db/log_test.cc
table/table_test.cc
db/skiplist_test.cc
db/version_edit_test.cc
db/version_set_test.cc
db/write_batch_test.cc)
endif()
# TODO: memenv_test

27
src/leveldb/LICENSE
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@ -1,27 +0,0 @@
Copyright (c) 2011 The LevelDB Authors. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
* Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

17
src/leveldb/NEWS
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@ -1,17 +0,0 @@
Release 1.2 2011-05-16
----------------------
Fixes for larger databases (tested up to one billion 100-byte entries,
i.e., ~100GB).
(1) Place hard limit on number of level-0 files. This fixes errors
of the form "too many open files".
(2) Fixed memtable management. Before the fix, a heavy write burst
could cause unbounded memory usage.
A fix for a logging bug where the reader would incorrectly complain
about corruption.
Allow public access to WriteBatch contents so that users can easily
wrap a DB.

51
src/leveldb/README
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@ -1,51 +0,0 @@
leveldb: A key-value store
Authors: Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
The code under this directory implements a system for maintaining a
persistent key/value store.
See doc/index.html for more explanation.
See doc/impl.html for a brief overview of the implementation.
The public interface is in include/*.h. Callers should not include or
rely on the details of any other header files in this package. Those
internal APIs may be changed without warning.
Guide to header files:
include/db.h
Main interface to the DB: Start here
include/options.h
Control over the behavior of an entire database, and also
control over the behavior of individual reads and writes.
include/comparator.h
Abstraction for user-specified comparison function. If you want
just bytewise comparison of keys, you can use the default comparator,
but clients can write their own comparator implementations if they
want custom ordering (e.g. to handle different character
encodings, etc.)
include/iterator.h
Interface for iterating over data. You can get an iterator
from a DB object.
include/write_batch.h
Interface for atomically applying multiple updates to a database.
include/slice.h
A simple module for maintaining a pointer and a length into some
other byte array.
include/status.h
Status is returned from many of the public interfaces and is used
to report success and various kinds of errors.
include/env.h
Abstraction of the OS environment. A posix implementation of
this interface is in util/env_posix.cc
include/table.h
include/table_builder.h
Lower-level modules that most clients probably won't use directly

14
src/leveldb/TODO
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@ -1,14 +0,0 @@
ss
- Stats
db
- Maybe implement DB::BulkDeleteForRange(start_key, end_key)
that would blow away files whose ranges are entirely contained
within [start_key..end_key]? For Chrome, deletion of obsolete
object stores, etc. can be done in the background anyway, so
probably not that important.
- There have been requests for MultiGet.
After a range is completely deleted, what gets rid of the
corresponding files if we do no future changes to that range. Make
the conditions for triggering compactions fire in more situations?

202
src/leveldb/build_detect_platform
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@ -1,202 +0,0 @@
#!/bin/sh
#
# Detects OS we're compiling on and outputs a file specified by the first
# argument, which in turn gets read while processing Makefile.
#
# The output will set the following variables:
# CC C Compiler path
# CXX C++ Compiler path
# PLATFORM_LDFLAGS Linker flags
# PLATFORM_LIBS Libraries flags
# PLATFORM_SHARED_EXT Extension for shared libraries
# PLATFORM_SHARED_LDFLAGS Flags for building shared library
# This flag is embedded just before the name
# of the shared library without intervening spaces
# PLATFORM_SHARED_CFLAGS Flags for compiling objects for shared library
# PLATFORM_CCFLAGS C compiler flags
# PLATFORM_CXXFLAGS C++ compiler flags. Will contain:
# PLATFORM_SHARED_VERSIONED Set to 'true' if platform supports versioned
# shared libraries, empty otherwise.
#
# The PLATFORM_CCFLAGS and PLATFORM_CXXFLAGS might include the following:
#
# -DLEVELDB_CSTDATOMIC_PRESENT if <cstdatomic> is present
# -DLEVELDB_PLATFORM_POSIX for Posix-based platforms
# -DSNAPPY if the Snappy library is present
#
OUTPUT=$1
PREFIX=$2
if test -z "$OUTPUT" || test -z "$PREFIX"; then
echo "usage: $0 <output-filename> <directory_prefix>" >&2
exit 1
fi
# Delete existing output, if it exists
rm -f $OUTPUT
touch $OUTPUT
if test -z "$CC"; then
CC=cc
fi
if test -z "$CXX"; then
CXX=g++
fi
# Detect OS
if test -z "$TARGET_OS"; then
TARGET_OS=`uname -s`
fi
COMMON_FLAGS=
CROSS_COMPILE=
PLATFORM_CCFLAGS=
PLATFORM_CXXFLAGS=
PLATFORM_LDFLAGS=
PLATFORM_LIBS=
PLATFORM_SHARED_EXT="so"
PLATFORM_SHARED_LDFLAGS="-shared -Wl,-soname -Wl,"
PLATFORM_SHARED_CFLAGS="-fPIC"
PLATFORM_SHARED_VERSIONED=true
MEMCMP_FLAG=
if [ "$CXX" = "g++" ]; then
# Use libc's memcmp instead of GCC's memcmp. This results in ~40%
# performance improvement on readrandom under gcc 4.4.3 on Linux/x86.
MEMCMP_FLAG="-fno-builtin-memcmp"
fi
case "$TARGET_OS" in
Darwin)
PLATFORM=OS_MACOSX
COMMON_FLAGS="$MEMCMP_FLAG -DOS_MACOSX"
PLATFORM_SHARED_EXT=dylib
[ -z "$INSTALL_PATH" ] && INSTALL_PATH=`pwd`
PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name $INSTALL_PATH/"
PORT_FILE=port/port_posix.cc
;;
Linux)
PLATFORM=OS_LINUX
COMMON_FLAGS="$MEMCMP_FLAG -pthread -DOS_LINUX"
PLATFORM_LDFLAGS="-pthread"
PORT_FILE=port/port_posix.cc
;;
SunOS)
PLATFORM=OS_SOLARIS
COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_SOLARIS"
PLATFORM_LIBS="-lpthread -lrt"
PORT_FILE=port/port_posix.cc
;;
FreeBSD)
PLATFORM=OS_FREEBSD
COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_FREEBSD"
PLATFORM_LIBS="-lpthread"
PORT_FILE=port/port_posix.cc
;;
NetBSD)
PLATFORM=OS_NETBSD
COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_NETBSD"
PLATFORM_LIBS="-lpthread -lgcc_s"
PORT_FILE=port/port_posix.cc
;;
OpenBSD)
PLATFORM=OS_OPENBSD
COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_OPENBSD"
PLATFORM_LDFLAGS="-pthread"
PORT_FILE=port/port_posix.cc
;;
DragonFly)
PLATFORM=OS_DRAGONFLYBSD
COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_DRAGONFLYBSD"
PLATFORM_LIBS="-lpthread"
PORT_FILE=port/port_posix.cc
;;
OS_ANDROID_CROSSCOMPILE)
PLATFORM=OS_ANDROID
COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_ANDROID -DLEVELDB_PLATFORM_POSIX"
PLATFORM_LDFLAGS="" # All pthread features are in the Android C library
PORT_FILE=port/port_posix.cc
CROSS_COMPILE=true
;;
HP-UX)
PLATFORM=OS_HPUX
COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_HPUX"
PLATFORM_LDFLAGS="-pthread"
PORT_FILE=port/port_posix.cc
# man ld: +h internal_name
PLATFORM_SHARED_LDFLAGS="-shared -Wl,+h -Wl,"
;;
*)
echo "Unknown platform!" >&2
exit 1
esac
# We want to make a list of all cc files within util, db, table, and helpers
# except for the test and benchmark files. By default, find will output a list
# of all files matching either rule, so we need to append -print to make the
# prune take effect.
DIRS="$PREFIX/db $PREFIX/util $PREFIX/table"
set -f # temporarily disable globbing so that our patterns aren't expanded
PRUNE_TEST="-name *test*.cc -prune"
PRUNE_BENCH="-name *_bench.cc -prune"
PORTABLE_FILES=`find $DIRS $PRUNE_TEST -o $PRUNE_BENCH -o -name '*.cc' -print | sort | sed "s,^$PREFIX/,," | tr "\n" " "`
set +f # re-enable globbing
# The sources consist of the portable files, plus the platform-specific port
# file.
echo "SOURCES=$PORTABLE_FILES $PORT_FILE" >> $OUTPUT
echo "MEMENV_SOURCES=helpers/memenv/memenv.cc" >> $OUTPUT
if [ "$CROSS_COMPILE" = "true" ]; then
# Cross-compiling; do not try any compilation tests.
true
else
# If -std=c++0x works, use <cstdatomic>. Otherwise use port_posix.h.
$CXX $CXXFLAGS -std=c++0x -x c++ - -o /dev/null 2>/dev/null <<EOF
#include <cstdatomic>
int main() {}
EOF
if [ "$?" = 0 ]; then
COMMON_FLAGS="$COMMON_FLAGS -DLEVELDB_PLATFORM_POSIX -DLEVELDB_CSTDATOMIC_PRESENT"
PLATFORM_CXXFLAGS="-std=c++0x"
else
COMMON_FLAGS="$COMMON_FLAGS -DLEVELDB_PLATFORM_POSIX"
fi
# Test whether Snappy library is installed
# http://code.google.com/p/snappy/
$CXX $CXXFLAGS -x c++ - -o /dev/null 2>/dev/null <<EOF
#include <snappy.h>
int main() {}
EOF
if [ "$?" = 0 ]; then
COMMON_FLAGS="$COMMON_FLAGS -DSNAPPY"
PLATFORM_LIBS="$PLATFORM_LIBS -lsnappy"
fi
# Test whether tcmalloc is available
$CXX $CXXFLAGS -x c++ - -o /dev/null -ltcmalloc 2>/dev/null <<EOF
int main() {}
EOF
if [ "$?" = 0 ]; then
PLATFORM_LIBS="$PLATFORM_LIBS -ltcmalloc"
fi
fi
PLATFORM_CCFLAGS="$PLATFORM_CCFLAGS $COMMON_FLAGS"
PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS $COMMON_FLAGS"
echo "CC=$CC" >> $OUTPUT
echo "CXX=$CXX" >> $OUTPUT
echo "PLATFORM=$PLATFORM" >> $OUTPUT
echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> $OUTPUT
echo "PLATFORM_LIBS=$PLATFORM_LIBS" >> $OUTPUT
echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> $OUTPUT
echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> $OUTPUT
echo "PLATFORM_SHARED_CFLAGS=$PLATFORM_SHARED_CFLAGS" >> $OUTPUT
echo "PLATFORM_SHARED_EXT=$PLATFORM_SHARED_EXT" >> $OUTPUT
echo "PLATFORM_SHARED_LDFLAGS=$PLATFORM_SHARED_LDFLAGS" >> $OUTPUT
echo "PLATFORM_SHARED_VERSIONED=$PLATFORM_SHARED_VERSIONED" >> $OUTPUT

88
src/leveldb/db/builder.cc
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@ -1,88 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/builder.h"
#include "db/filename.h"
#include "db/dbformat.h"
#include "db/table_cache.h"
#include "db/version_edit.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "leveldb/iterator.h"
namespace leveldb {
Status BuildTable(const std::string& dbname,
Env* env,
const Options& options,
TableCache* table_cache,
Iterator* iter,
FileMetaData* meta) {
Status s;
meta->file_size = 0;
iter->SeekToFirst();
std::string fname = TableFileName(dbname, meta->number);
if (iter->Valid()) {
WritableFile* file;
s = env->NewWritableFile(fname, &file);
if (!s.ok()) {
return s;
}
TableBuilder* builder = new TableBuilder(options, file);
meta->smallest.DecodeFrom(iter->key());
for (; iter->Valid(); iter->Next()) {
Slice key = iter->key();
meta->largest.DecodeFrom(key);
builder->Add(key, iter->value());
}
// Finish and check for builder errors
if (s.ok()) {
s = builder->Finish();
if (s.ok()) {
meta->file_size = builder->FileSize();
assert(meta->file_size > 0);
}
} else {
builder->Abandon();
}
delete builder;
// Finish and check for file errors
if (s.ok()) {
s = file->Sync();
}
if (s.ok()) {
s = file->Close();
}
delete file;
file = NULL;
if (s.ok()) {
// Verify that the table is usable
Iterator* it = table_cache->NewIterator(ReadOptions(),
meta->number,
meta->file_size);
s = it->status();
delete it;
}
}
// Check for input iterator errors
if (!iter->status().ok()) {
s = iter->status();
}
if (s.ok() && meta->file_size > 0) {
// Keep it
} else {
env->DeleteFile(fname);
}
return s;
}
} // namespace leveldb

34
src/leveldb/db/builder.h
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@ -1,34 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_BUILDER_H_
#define STORAGE_LEVELDB_DB_BUILDER_H_
#include "leveldb/status.h"
namespace leveldb {
struct Options;
struct FileMetaData;
class Env;
class Iterator;
class TableCache;
class VersionEdit;
// Build a Table file from the contents of *iter. The generated file
// will be named according to meta->number. On success, the rest of
// *meta will be filled with metadata about the generated table.
// If no data is present in *iter, meta->file_size will be set to
// zero, and no Table file will be produced.
extern Status BuildTable(const std::string& dbname,
Env* env,
const Options& options,
TableCache* table_cache,
Iterator* iter,
FileMetaData* meta);
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_BUILDER_H_

595
src/leveldb/db/c.cc
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@ -1,595 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "leveldb/c.h"
#include <stdlib.h>
#include <unistd.h>
#include "leveldb/cache.h"
#include "leveldb/comparator.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "leveldb/filter_policy.h"
#include "leveldb/iterator.h"
#include "leveldb/options.h"
#include "leveldb/status.h"
#include "leveldb/write_batch.h"
using leveldb::Cache;
using leveldb::Comparator;
using leveldb::CompressionType;
using leveldb::DB;
using leveldb::Env;
using leveldb::FileLock;
using leveldb::FilterPolicy;
using leveldb::Iterator;
using leveldb::kMajorVersion;
using leveldb::kMinorVersion;
using leveldb::Logger;
using leveldb::NewBloomFilterPolicy;
using leveldb::NewLRUCache;
using leveldb::Options;
using leveldb::RandomAccessFile;
using leveldb::Range;
using leveldb::ReadOptions;
using leveldb::SequentialFile;
using leveldb::Slice;
using leveldb::Snapshot;
using leveldb::Status;
using leveldb::WritableFile;
using leveldb::WriteBatch;
using leveldb::WriteOptions;
extern "C" {
struct leveldb_t { DB* rep; };
struct leveldb_iterator_t { Iterator* rep; };
struct leveldb_writebatch_t { WriteBatch rep; };
struct leveldb_snapshot_t { const Snapshot* rep; };
struct leveldb_readoptions_t { ReadOptions rep; };
struct leveldb_writeoptions_t { WriteOptions rep; };
struct leveldb_options_t { Options rep; };
struct leveldb_cache_t { Cache* rep; };
struct leveldb_seqfile_t { SequentialFile* rep; };
struct leveldb_randomfile_t { RandomAccessFile* rep; };
struct leveldb_writablefile_t { WritableFile* rep; };
struct leveldb_logger_t { Logger* rep; };
struct leveldb_filelock_t { FileLock* rep; };
struct leveldb_comparator_t : public Comparator {
void* state_;
void (*destructor_)(void*);
int (*compare_)(
void*,
const char* a, size_t alen,
const char* b, size_t blen);
const char* (*name_)(void*);
virtual ~leveldb_comparator_t() {
(*destructor_)(state_);
}
virtual int Compare(const Slice& a, const Slice& b) const {
return (*compare_)(state_, a.data(), a.size(), b.data(), b.size());
}
virtual const char* Name() const {
return (*name_)(state_);
}
// No-ops since the C binding does not support key shortening methods.
virtual void FindShortestSeparator(std::string*, const Slice&) const { }
virtual void FindShortSuccessor(std::string* key) const { }
};
struct leveldb_filterpolicy_t : public FilterPolicy {
void* state_;
void (*destructor_)(void*);
const char* (*name_)(void*);
char* (*create_)(
void*,
const char* const* key_array, const size_t* key_length_array,
int num_keys,
size_t* filter_length);
unsigned char (*key_match_)(
void*,
const char* key, size_t length,
const char* filter, size_t filter_length);
virtual ~leveldb_filterpolicy_t() {
(*destructor_)(state_);
}
virtual const char* Name() const {
return (*name_)(state_);
}
virtual void CreateFilter(const Slice* keys, int n, std::string* dst) const {
std::vector<const char*> key_pointers(n);
std::vector<size_t> key_sizes(n);
for (int i = 0; i < n; i++) {
key_pointers[i] = keys[i].data();
key_sizes[i] = keys[i].size();
}
size_t len;
char* filter = (*create_)(state_, &key_pointers[0], &key_sizes[0], n, &len);
dst->append(filter, len);
free(filter);
}
virtual bool KeyMayMatch(const Slice& key, const Slice& filter) const {
return (*key_match_)(state_, key.data(), key.size(),
filter.data(), filter.size());
}
};
struct leveldb_env_t {
Env* rep;
bool is_default;
};
static bool SaveError(char** errptr, const Status& s) {
assert(errptr != NULL);
if (s.ok()) {
return false;
} else if (*errptr == NULL) {
*errptr = strdup(s.ToString().c_str());
} else {
// TODO(sanjay): Merge with existing error?
free(*errptr);
*errptr = strdup(s.ToString().c_str());
}
return true;
}
static char* CopyString(const std::string& str) {
char* result = reinterpret_cast<char*>(malloc(sizeof(char) * str.size()));
memcpy(result, str.data(), sizeof(char) * str.size());
return result;
}
leveldb_t* leveldb_open(
const leveldb_options_t* options,
const char* name,
char** errptr) {
DB* db;
if (SaveError(errptr, DB::Open(options->rep, std::string(name), &db))) {
return NULL;
}
leveldb_t* result = new leveldb_t;
result->rep = db;
return result;
}
void leveldb_close(leveldb_t* db) {
delete db->rep;
delete db;
}
void leveldb_put(
leveldb_t* db,
const leveldb_writeoptions_t* options,
const char* key, size_t keylen,
const char* val, size_t vallen,
char** errptr) {
SaveError(errptr,
db->rep->Put(options->rep, Slice(key, keylen), Slice(val, vallen)));
}
void leveldb_delete(
leveldb_t* db,
const leveldb_writeoptions_t* options,
const char* key, size_t keylen,
char** errptr) {
SaveError(errptr, db->rep->Delete(options->rep, Slice(key, keylen)));
}
void leveldb_write(
leveldb_t* db,
const leveldb_writeoptions_t* options,
leveldb_writebatch_t* batch,
char** errptr) {
SaveError(errptr, db->rep->Write(options->rep, &batch->rep));
}
char* leveldb_get(
leveldb_t* db,
const leveldb_readoptions_t* options,
const char* key, size_t keylen,
size_t* vallen,
char** errptr) {
char* result = NULL;
std::string tmp;
Status s = db->rep->Get(options->rep, Slice(key, keylen), &tmp);
if (s.ok()) {
*vallen = tmp.size();
result = CopyString(tmp);
} else {
*vallen = 0;
if (!s.IsNotFound()) {
SaveError(errptr, s);
}
}
return result;
}
leveldb_iterator_t* leveldb_create_iterator(
leveldb_t* db,
const leveldb_readoptions_t* options) {
leveldb_iterator_t* result = new leveldb_iterator_t;
result->rep = db->rep->NewIterator(options->rep);
return result;
}
const leveldb_snapshot_t* leveldb_create_snapshot(
leveldb_t* db) {
leveldb_snapshot_t* result = new leveldb_snapshot_t;
result->rep = db->rep->GetSnapshot();
return result;
}
void leveldb_release_snapshot(
leveldb_t* db,
const leveldb_snapshot_t* snapshot) {
db->rep->ReleaseSnapshot(snapshot->rep);
delete snapshot;
}
char* leveldb_property_value(
leveldb_t* db,
const char* propname) {
std::string tmp;
if (db->rep->GetProperty(Slice(propname), &tmp)) {
// We use strdup() since we expect human readable output.
return strdup(tmp.c_str());
} else {
return NULL;
}
}
void leveldb_approximate_sizes(
leveldb_t* db,
int num_ranges,
const char* const* range_start_key, const size_t* range_start_key_len,
const char* const* range_limit_key, const size_t* range_limit_key_len,
uint64_t* sizes) {
Range* ranges = new Range[num_ranges];
for (int i = 0; i < num_ranges; i++) {
ranges[i].start = Slice(range_start_key[i], range_start_key_len[i]);
ranges[i].limit = Slice(range_limit_key[i], range_limit_key_len[i]);
}
db->rep->GetApproximateSizes(ranges, num_ranges, sizes);
delete[] ranges;
}
void leveldb_compact_range(
leveldb_t* db,
const char* start_key, size_t start_key_len,
const char* limit_key, size_t limit_key_len) {
Slice a, b;
db->rep->CompactRange(
// Pass NULL Slice if corresponding "const char*" is NULL
(start_key ? (a = Slice(start_key, start_key_len), &a) : NULL),
(limit_key ? (b = Slice(limit_key, limit_key_len), &b) : NULL));
}
void leveldb_destroy_db(
const leveldb_options_t* options,
const char* name,
char** errptr) {
SaveError(errptr, DestroyDB(name, options->rep));
}
void leveldb_repair_db(
const leveldb_options_t* options,
const char* name,
char** errptr) {
SaveError(errptr, RepairDB(name, options->rep));
}
void leveldb_iter_destroy(leveldb_iterator_t* iter) {
delete iter->rep;
delete iter;
}
unsigned char leveldb_iter_valid(const leveldb_iterator_t* iter) {
return iter->rep->Valid();
}
void leveldb_iter_seek_to_first(leveldb_iterator_t* iter) {
iter->rep->SeekToFirst();
}
void leveldb_iter_seek_to_last(leveldb_iterator_t* iter) {
iter->rep->SeekToLast();
}
void leveldb_iter_seek(leveldb_iterator_t* iter, const char* k, size_t klen) {
iter->rep->Seek(Slice(k, klen));
}
void leveldb_iter_next(leveldb_iterator_t* iter) {
iter->rep->Next();
}
void leveldb_iter_prev(leveldb_iterator_t* iter) {
iter->rep->Prev();
}
const char* leveldb_iter_key(const leveldb_iterator_t* iter, size_t* klen) {
Slice s = iter->rep->key();
*klen = s.size();
return s.data();
}
const char* leveldb_iter_value(const leveldb_iterator_t* iter, size_t* vlen) {
Slice s = iter->rep->value();
*vlen = s.size();
return s.data();
}
void leveldb_iter_get_error(const leveldb_iterator_t* iter, char** errptr) {
SaveError(errptr, iter->rep->status());
}
leveldb_writebatch_t* leveldb_writebatch_create() {
return new leveldb_writebatch_t;
}
void leveldb_writebatch_destroy(leveldb_writebatch_t* b) {
delete b;
}
void leveldb_writebatch_clear(leveldb_writebatch_t* b) {
b->rep.Clear();
}
void leveldb_writebatch_put(
leveldb_writebatch_t* b,
const char* key, size_t klen,
const char* val, size_t vlen) {
b->rep.Put(Slice(key, klen), Slice(val, vlen));
}
void leveldb_writebatch_delete(
leveldb_writebatch_t* b,
const char* key, size_t klen) {
b->rep.Delete(Slice(key, klen));
}
void leveldb_writebatch_iterate(
leveldb_writebatch_t* b,
void* state,
void (*put)(void*, const char* k, size_t klen, const char* v, size_t vlen),
void (*deleted)(void*, const char* k, size_t klen)) {
class H : public WriteBatch::Handler {
public:
void* state_;
void (*put_)(void*, const char* k, size_t klen, const char* v, size_t vlen);
void (*deleted_)(void*, const char* k, size_t klen);
virtual void Put(const Slice& key, const Slice& value) {
(*put_)(state_, key.data(), key.size(), value.data(), value.size());
}
virtual void Delete(const Slice& key) {
(*deleted_)(state_, key.data(), key.size());
}
};
H handler;
handler.state_ = state;
handler.put_ = put;
handler.deleted_ = deleted;
b->rep.Iterate(&handler);
}
leveldb_options_t* leveldb_options_create() {
return new leveldb_options_t;
}
void leveldb_options_destroy(leveldb_options_t* options) {
delete options;
}
void leveldb_options_set_comparator(
leveldb_options_t* opt,
leveldb_comparator_t* cmp) {
opt->rep.comparator = cmp;
}
void leveldb_options_set_filter_policy(
leveldb_options_t* opt,
leveldb_filterpolicy_t* policy) {
opt->rep.filter_policy = policy;
}
void leveldb_options_set_create_if_missing(
leveldb_options_t* opt, unsigned char v) {
opt->rep.create_if_missing = v;
}
void leveldb_options_set_error_if_exists(
leveldb_options_t* opt, unsigned char v) {
opt->rep.error_if_exists = v;
}
void leveldb_options_set_paranoid_checks(
leveldb_options_t* opt, unsigned char v) {
opt->rep.paranoid_checks = v;
}
void leveldb_options_set_env(leveldb_options_t* opt, leveldb_env_t* env) {
opt->rep.env = (env ? env->rep : NULL);
}
void leveldb_options_set_info_log(leveldb_options_t* opt, leveldb_logger_t* l) {
opt->rep.info_log = (l ? l->rep : NULL);
}
void leveldb_options_set_write_buffer_size(leveldb_options_t* opt, size_t s) {
opt->rep.write_buffer_size = s;
}
void leveldb_options_set_max_open_files(leveldb_options_t* opt, int n) {
opt->rep.max_open_files = n;
}
void leveldb_options_set_cache(leveldb_options_t* opt, leveldb_cache_t* c) {
opt->rep.block_cache = c->rep;
}
void leveldb_options_set_block_size(leveldb_options_t* opt, size_t s) {
opt->rep.block_size = s;
}
void leveldb_options_set_block_restart_interval(leveldb_options_t* opt, int n) {
opt->rep.block_restart_interval = n;
}
void leveldb_options_set_compression(leveldb_options_t* opt, int t) {
opt->rep.compression = static_cast<CompressionType>(t);
}
leveldb_comparator_t* leveldb_comparator_create(
void* state,
void (*destructor)(void*),
int (*compare)(
void*,
const char* a, size_t alen,
const char* b, size_t blen),
const char* (*name)(void*)) {
leveldb_comparator_t* result = new leveldb_comparator_t;
result->state_ = state;
result->destructor_ = destructor;
result->compare_ = compare;
result->name_ = name;
return result;
}
void leveldb_comparator_destroy(leveldb_comparator_t* cmp) {
delete cmp;
}
leveldb_filterpolicy_t* leveldb_filterpolicy_create(
void* state,
void (*destructor)(void*),
char* (*create_filter)(
void*,
const char* const* key_array, const size_t* key_length_array,
int num_keys,
size_t* filter_length),
unsigned char (*key_may_match)(
void*,
const char* key, size_t length,
const char* filter, size_t filter_length),
const char* (*name)(void*)) {
leveldb_filterpolicy_t* result = new leveldb_filterpolicy_t;
result->state_ = state;
result->destructor_ = destructor;
result->create_ = create_filter;
result->key_match_ = key_may_match;
result->name_ = name;
return result;
}
void leveldb_filterpolicy_destroy(leveldb_filterpolicy_t* filter) {
delete filter;
}
leveldb_filterpolicy_t* leveldb_filterpolicy_create_bloom(int bits_per_key) {
// Make a leveldb_filterpolicy_t, but override all of its methods so
// they delegate to a NewBloomFilterPolicy() instead of user
// supplied C functions.
struct Wrapper : public leveldb_filterpolicy_t {
const FilterPolicy* rep_;
~Wrapper() { delete rep_; }
const char* Name() const { return rep_->Name(); }
void CreateFilter(const Slice* keys, int n, std::string* dst) const {
return rep_->CreateFilter(keys, n, dst);
}
bool KeyMayMatch(const Slice& key, const Slice& filter) const {
return rep_->KeyMayMatch(key, filter);
}
static void DoNothing(void*) { }
};
Wrapper* wrapper = new Wrapper;
wrapper->rep_ = NewBloomFilterPolicy(bits_per_key);
wrapper->state_ = NULL;
wrapper->destructor_ = &Wrapper::DoNothing;
return wrapper;
}
leveldb_readoptions_t* leveldb_readoptions_create() {
return new leveldb_readoptions_t;
}
void leveldb_readoptions_destroy(leveldb_readoptions_t* opt) {
delete opt;
}
void leveldb_readoptions_set_verify_checksums(
leveldb_readoptions_t* opt,
unsigned char v) {
opt->rep.verify_checksums = v;
}
void leveldb_readoptions_set_fill_cache(
leveldb_readoptions_t* opt, unsigned char v) {
opt->rep.fill_cache = v;
}
void leveldb_readoptions_set_snapshot(
leveldb_readoptions_t* opt,
const leveldb_snapshot_t* snap) {
opt->rep.snapshot = (snap ? snap->rep : NULL);
}
leveldb_writeoptions_t* leveldb_writeoptions_create() {
return new leveldb_writeoptions_t;
}
void leveldb_writeoptions_destroy(leveldb_writeoptions_t* opt) {
delete opt;
}
void leveldb_writeoptions_set_sync(
leveldb_writeoptions_t* opt, unsigned char v) {
opt->rep.sync = v;
}
leveldb_cache_t* leveldb_cache_create_lru(size_t capacity) {
leveldb_cache_t* c = new leveldb_cache_t;
c->rep = NewLRUCache(capacity);
return c;
}
void leveldb_cache_destroy(leveldb_cache_t* cache) {
delete cache->rep;
delete cache;
}
leveldb_env_t* leveldb_create_default_env() {
leveldb_env_t* result = new leveldb_env_t;
result->rep = Env::Default();
result->is_default = true;
return result;
}
void leveldb_env_destroy(leveldb_env_t* env) {
if (!env->is_default) delete env->rep;
delete env;
}
void leveldb_free(void* ptr) {
free(ptr);
}
int leveldb_major_version() {
return kMajorVersion;
}
int leveldb_minor_version() {
return kMinorVersion;
}
} // end extern "C"

390
src/leveldb/db/c_test.c
View File

@ -1,390 +0,0 @@
/* Copyright (c) 2011 The LevelDB Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file. See the AUTHORS file for names of contributors. */
#include "leveldb/c.h"
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
const char* phase = "";
static char dbname[200];
static void StartPhase(const char* name) {
fprintf(stderr, "=== Test %s\n", name);
phase = name;
}
static const char* GetTempDir(void) {
const char* ret = getenv("TEST_TMPDIR");
if (ret == NULL || ret[0] == '\0')
ret = "/tmp";
return ret;
}
#define CheckNoError(err) \
if ((err) != NULL) { \
fprintf(stderr, "%s:%d: %s: %s\n", __FILE__, __LINE__, phase, (err)); \
abort(); \
}
#define CheckCondition(cond) \
if (!(cond)) { \
fprintf(stderr, "%s:%d: %s: %s\n", __FILE__, __LINE__, phase, #cond); \
abort(); \
}
static void CheckEqual(const char* expected, const char* v, size_t n) {
if (expected == NULL && v == NULL) {
// ok
} else if (expected != NULL && v != NULL && n == strlen(expected) &&
memcmp(expected, v, n) == 0) {
// ok
return;
} else {
fprintf(stderr, "%s: expected '%s', got '%s'\n",
phase,
(expected ? expected : "(null)"),
(v ? v : "(null"));
abort();
}
}
static void Free(char** ptr) {
if (*ptr) {
free(*ptr);
*ptr = NULL;
}
}
static void CheckGet(
leveldb_t* db,
const leveldb_readoptions_t* options,
const char* key,
const char* expected) {
char* err = NULL;
size_t val_len;
char* val;
val = leveldb_get(db, options, key, strlen(key), &val_len, &err);
CheckNoError(err);
CheckEqual(expected, val, val_len);
Free(&val);
}
static void CheckIter(leveldb_iterator_t* iter,
const char* key, const char* val) {
size_t len;
const char* str;
str = leveldb_iter_key(iter, &len);
CheckEqual(key, str, len);
str = leveldb_iter_value(iter, &len);
CheckEqual(val, str, len);
}
// Callback from leveldb_writebatch_iterate()
static void CheckPut(void* ptr,
const char* k, size_t klen,
const char* v, size_t vlen) {
int* state = (int*) ptr;
CheckCondition(*state < 2);
switch (*state) {
case 0:
CheckEqual("bar", k, klen);
CheckEqual("b", v, vlen);
break;
case 1:
CheckEqual("box", k, klen);
CheckEqual("c", v, vlen);
break;
}
(*state)++;
}
// Callback from leveldb_writebatch_iterate()
static void CheckDel(void* ptr, const char* k, size_t klen) {
int* state = (int*) ptr;
CheckCondition(*state == 2);
CheckEqual("bar", k, klen);
(*state)++;
}
static void CmpDestroy(void* arg) { }
static int CmpCompare(void* arg, const char* a, size_t alen,
const char* b, size_t blen) {
int n = (alen < blen) ? alen : blen;
int r = memcmp(a, b, n);
if (r == 0) {
if (alen < blen) r = -1;
else if (alen > blen) r = +1;
}
return r;
}
static const char* CmpName(void* arg) {
return "foo";
}
// Custom filter policy
static unsigned char fake_filter_result = 1;
static void FilterDestroy(void* arg) { }
static const char* FilterName(void* arg) {
return "TestFilter";
}
static char* FilterCreate(
void* arg,
const char* const* key_array, const size_t* key_length_array,
int num_keys,
size_t* filter_length) {
*filter_length = 4;
char* result = malloc(4);
memcpy(result, "fake", 4);
return result;
}
unsigned char FilterKeyMatch(
void* arg,
const char* key, size_t length,
const char* filter, size_t filter_length) {
CheckCondition(filter_length == 4);
CheckCondition(memcmp(filter, "fake", 4) == 0);
return fake_filter_result;
}
int main(int argc, char** argv) {
leveldb_t* db;
leveldb_comparator_t* cmp;
leveldb_cache_t* cache;
leveldb_env_t* env;
leveldb_options_t* options;
leveldb_readoptions_t* roptions;
leveldb_writeoptions_t* woptions;
char* err = NULL;
int run = -1;
CheckCondition(leveldb_major_version() >= 1);
CheckCondition(leveldb_minor_version() >= 1);
snprintf(dbname, sizeof(dbname),
"%s/leveldb_c_test-%d",
GetTempDir(),
((int) geteuid()));
StartPhase("create_objects");
cmp = leveldb_comparator_create(NULL, CmpDestroy, CmpCompare, CmpName);
env = leveldb_create_default_env();
cache = leveldb_cache_create_lru(100000);
options = leveldb_options_create();
leveldb_options_set_comparator(options, cmp);
leveldb_options_set_error_if_exists(options, 1);
leveldb_options_set_cache(options, cache);
leveldb_options_set_env(options, env);
leveldb_options_set_info_log(options, NULL);
leveldb_options_set_write_buffer_size(options, 100000);
leveldb_options_set_paranoid_checks(options, 1);
leveldb_options_set_max_open_files(options, 10);
leveldb_options_set_block_size(options, 1024);
leveldb_options_set_block_restart_interval(options, 8);
leveldb_options_set_compression(options, leveldb_no_compression);
roptions = leveldb_readoptions_create();
leveldb_readoptions_set_verify_checksums(roptions, 1);
leveldb_readoptions_set_fill_cache(roptions, 0);
woptions = leveldb_writeoptions_create();
leveldb_writeoptions_set_sync(woptions, 1);
StartPhase("destroy");
leveldb_destroy_db(options, dbname, &err);
Free(&err);
StartPhase("open_error");
db = leveldb_open(options, dbname, &err);
CheckCondition(err != NULL);
Free(&err);
StartPhase("leveldb_free");
db = leveldb_open(options, dbname, &err);
CheckCondition(err != NULL);
leveldb_free(err);
err = NULL;
StartPhase("open");
leveldb_options_set_create_if_missing(options, 1);
db = leveldb_open(options, dbname, &err);
CheckNoError(err);
CheckGet(db, roptions, "foo", NULL);
StartPhase("put");
leveldb_put(db, woptions, "foo", 3, "hello", 5, &err);
CheckNoError(err);
CheckGet(db, roptions, "foo", "hello");
StartPhase("compactall");
leveldb_compact_range(db, NULL, 0, NULL, 0);
CheckGet(db, roptions, "foo", "hello");
StartPhase("compactrange");
leveldb_compact_range(db, "a", 1, "z", 1);
CheckGet(db, roptions, "foo", "hello");
StartPhase("writebatch");
{
leveldb_writebatch_t* wb = leveldb_writebatch_create();
leveldb_writebatch_put(wb, "foo", 3, "a", 1);
leveldb_writebatch_clear(wb);
leveldb_writebatch_put(wb, "bar", 3, "b", 1);
leveldb_writebatch_put(wb, "box", 3, "c", 1);
leveldb_writebatch_delete(wb, "bar", 3);
leveldb_write(db, woptions, wb, &err);
CheckNoError(err);
CheckGet(db, roptions, "foo", "hello");
CheckGet(db, roptions, "bar", NULL);
CheckGet(db, roptions, "box", "c");
int pos = 0;
leveldb_writebatch_iterate(wb, &pos, CheckPut, CheckDel);
CheckCondition(pos == 3);
leveldb_writebatch_destroy(wb);
}
StartPhase("iter");
{
leveldb_iterator_t* iter = leveldb_create_iterator(db, roptions);
CheckCondition(!leveldb_iter_valid(iter));
leveldb_iter_seek_to_first(iter);
CheckCondition(leveldb_iter_valid(iter));
CheckIter(iter, "box", "c");
leveldb_iter_next(iter);
CheckIter(iter, "foo", "hello");
leveldb_iter_prev(iter);
CheckIter(iter, "box", "c");
leveldb_iter_prev(iter);
CheckCondition(!leveldb_iter_valid(iter));
leveldb_iter_seek_to_last(iter);
CheckIter(iter, "foo", "hello");
leveldb_iter_seek(iter, "b", 1);
CheckIter(iter, "box", "c");
leveldb_iter_get_error(iter, &err);
CheckNoError(err);
leveldb_iter_destroy(iter);
}
StartPhase("approximate_sizes");
{
int i;
int n = 20000;
char keybuf[100];
char valbuf[100];
uint64_t sizes[2];
const char* start[2] = { "a", "k00000000000000010000" };
size_t start_len[2] = { 1, 21 };
const char* limit[2] = { "k00000000000000010000", "z" };
size_t limit_len[2] = { 21, 1 };
leveldb_writeoptions_set_sync(woptions, 0);
for (i = 0; i < n; i++) {
snprintf(keybuf, sizeof(keybuf), "k%020d", i);
snprintf(valbuf, sizeof(valbuf), "v%020d", i);
leveldb_put(db, woptions, keybuf, strlen(keybuf), valbuf, strlen(valbuf),
&err);
CheckNoError(err);
}
leveldb_approximate_sizes(db, 2, start, start_len, limit, limit_len, sizes);
CheckCondition(sizes[0] > 0);
CheckCondition(sizes[1] > 0);
}
StartPhase("property");
{
char* prop = leveldb_property_value(db, "nosuchprop");
CheckCondition(prop == NULL);
prop = leveldb_property_value(db, "leveldb.stats");
CheckCondition(prop != NULL);
Free(&prop);
}
StartPhase("snapshot");
{
const leveldb_snapshot_t* snap;
snap = leveldb_create_snapshot(db);
leveldb_delete(db, woptions, "foo", 3, &err);
CheckNoError(err);
leveldb_readoptions_set_snapshot(roptions, snap);
CheckGet(db, roptions, "foo", "hello");
leveldb_readoptions_set_snapshot(roptions, NULL);
CheckGet(db, roptions, "foo", NULL);
leveldb_release_snapshot(db, snap);
}
StartPhase("repair");
{
leveldb_close(db);
leveldb_options_set_create_if_missing(options, 0);
leveldb_options_set_error_if_exists(options, 0);
leveldb_repair_db(options, dbname, &err);
CheckNoError(err);
db = leveldb_open(options, dbname, &err);
CheckNoError(err);
CheckGet(db, roptions, "foo", NULL);
CheckGet(db, roptions, "bar", NULL);
CheckGet(db, roptions, "box", "c");
leveldb_options_set_create_if_missing(options, 1);
leveldb_options_set_error_if_exists(options, 1);
}
StartPhase("filter");
for (run = 0; run < 2; run++) {
// First run uses custom filter, second run uses bloom filter
CheckNoError(err);
leveldb_filterpolicy_t* policy;
if (run == 0) {
policy = leveldb_filterpolicy_create(
NULL, FilterDestroy, FilterCreate, FilterKeyMatch, FilterName);
} else {
policy = leveldb_filterpolicy_create_bloom(10);
}
// Create new database
leveldb_close(db);
leveldb_destroy_db(options, dbname, &err);
leveldb_options_set_filter_policy(options, policy);
db = leveldb_open(options, dbname, &err);
CheckNoError(err);
leveldb_put(db, woptions, "foo", 3, "foovalue", 8, &err);
CheckNoError(err);
leveldb_put(db, woptions, "bar", 3, "barvalue", 8, &err);
CheckNoError(err);
leveldb_compact_range(db, NULL, 0, NULL, 0);
fake_filter_result = 1;
CheckGet(db, roptions, "foo", "foovalue");
CheckGet(db, roptions, "bar", "barvalue");
if (phase == 0) {
// Must not find value when custom filter returns false
fake_filter_result = 0;
CheckGet(db, roptions, "foo", NULL);
CheckGet(db, roptions, "bar", NULL);
fake_filter_result = 1;
CheckGet(db, roptions, "foo", "foovalue");
CheckGet(db, roptions, "bar", "barvalue");
}
leveldb_options_set_filter_policy(options, NULL);
leveldb_filterpolicy_destroy(policy);
}
StartPhase("cleanup");
leveldb_close(db);
leveldb_options_destroy(options);
leveldb_readoptions_destroy(roptions);
leveldb_writeoptions_destroy(woptions);
leveldb_cache_destroy(cache);
leveldb_comparator_destroy(cmp);
leveldb_env_destroy(env);
fprintf(stderr, "PASS\n");
return 0;
}

359
src/leveldb/db/corruption_test.cc
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@ -1,359 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "leveldb/db.h"
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "leveldb/cache.h"
#include "leveldb/env.h"
#include "leveldb/table.h"
#include "leveldb/write_batch.h"
#include "db/db_impl.h"
#include "db/filename.h"
#include "db/log_format.h"
#include "db/version_set.h"
#include "util/logging.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace leveldb {
static const int kValueSize = 1000;
class CorruptionTest {
public:
test::ErrorEnv env_;
std::string dbname_;
Cache* tiny_cache_;
Options options_;
DB* db_;
CorruptionTest() {
tiny_cache_ = NewLRUCache(100);
options_.env = &env_;
dbname_ = test::TmpDir() + "/db_test";
DestroyDB(dbname_, options_);
db_ = NULL;
options_.create_if_missing = true;
Reopen();
options_.create_if_missing = false;
}
~CorruptionTest() {
delete db_;
DestroyDB(dbname_, Options());
delete tiny_cache_;
}
Status TryReopen(Options* options = NULL) {
delete db_;
db_ = NULL;
Options opt = (options ? *options : options_);
opt.env = &env_;
opt.block_cache = tiny_cache_;
return DB::Open(opt, dbname_, &db_);
}
void Reopen(Options* options = NULL) {
ASSERT_OK(TryReopen(options));
}
void RepairDB() {
delete db_;
db_ = NULL;
ASSERT_OK(::leveldb::RepairDB(dbname_, options_));
}
void Build(int n) {
std::string key_space, value_space;
WriteBatch batch;
for (int i = 0; i < n; i++) {
//if ((i % 100) == 0) fprintf(stderr, "@ %d of %d\n", i, n);
Slice key = Key(i, &key_space);
batch.Clear();
batch.Put(key, Value(i, &value_space));
ASSERT_OK(db_->Write(WriteOptions(), &batch));
}
}
void Check(int min_expected, int max_expected) {
int next_expected = 0;
int missed = 0;
int bad_keys = 0;
int bad_values = 0;
int correct = 0;
std::string value_space;
Iterator* iter = db_->NewIterator(ReadOptions());
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
uint64_t key;
Slice in(iter->key());
if (!ConsumeDecimalNumber(&in, &key) ||
!in.empty() ||
key < next_expected) {
bad_keys++;
continue;
}
missed += (key - next_expected);
next_expected = key + 1;
if (iter->value() != Value(key, &value_space)) {
bad_values++;
} else {
correct++;
}
}
delete iter;
fprintf(stderr,
"expected=%d..%d; got=%d; bad_keys=%d; bad_values=%d; missed=%d\n",
min_expected, max_expected, correct, bad_keys, bad_values, missed);
ASSERT_LE(min_expected, correct);
ASSERT_GE(max_expected, correct);
}
void Corrupt(FileType filetype, int offset, int bytes_to_corrupt) {
// Pick file to corrupt
std::vector<std::string> filenames;
ASSERT_OK(env_.GetChildren(dbname_, &filenames));
uint64_t number;
FileType type;
std::string fname;
int picked_number = -1;
for (int i = 0; i < filenames.size(); i++) {
if (ParseFileName(filenames[i], &number, &type) &&
type == filetype &&
int(number) > picked_number) { // Pick latest file
fname = dbname_ + "/" + filenames[i];
picked_number = number;
}
}
ASSERT_TRUE(!fname.empty()) << filetype;
struct stat sbuf;
if (stat(fname.c_str(), &sbuf) != 0) {
const char* msg = strerror(errno);
ASSERT_TRUE(false) << fname << ": " << msg;
}
if (offset < 0) {
// Relative to end of file; make it absolute
if (-offset > sbuf.st_size) {
offset = 0;
} else {
offset = sbuf.st_size + offset;
}
}
if (offset > sbuf.st_size) {
offset = sbuf.st_size;
}
if (offset + bytes_to_corrupt > sbuf.st_size) {
bytes_to_corrupt = sbuf.st_size - offset;
}
// Do it
std::string contents;
Status s = ReadFileToString(Env::Default(), fname, &contents);
ASSERT_TRUE(s.ok()) << s.ToString();
for (int i = 0; i < bytes_to_corrupt; i++) {
contents[i + offset] ^= 0x80;
}
s = WriteStringToFile(Env::Default(), contents, fname);
ASSERT_TRUE(s.ok()) << s.ToString();
}
int Property(const std::string& name) {
std::string property;
int result;
if (db_->GetProperty(name, &property) &&
sscanf(property.c_str(), "%d", &result) == 1) {
return result;
} else {
return -1;
}
}
// Return the ith key
Slice Key(int i, std::string* storage) {
char buf[100];
snprintf(buf, sizeof(buf), "%016d", i);
storage->assign(buf, strlen(buf));
return Slice(*storage);
}
// Return the value to associate with the specified key
Slice Value(int k, std::string* storage) {
Random r(k);
return test::RandomString(&r, kValueSize, storage);
}
};
TEST(CorruptionTest, Recovery) {
Build(100);
Check(100, 100);
Corrupt(kLogFile, 19, 1); // WriteBatch tag for first record
Corrupt(kLogFile, log::kBlockSize + 1000, 1); // Somewhere in second block
Reopen();
// The 64 records in the first two log blocks are completely lost.
Check(36, 36);
}
TEST(CorruptionTest, RecoverWriteError) {
env_.writable_file_error_ = true;
Status s = TryReopen();
ASSERT_TRUE(!s.ok());
}
TEST(CorruptionTest, NewFileErrorDuringWrite) {
// Do enough writing to force minor compaction
env_.writable_file_error_ = true;
const int num = 3 + (Options().write_buffer_size / kValueSize);
std::string value_storage;
Status s;
for (int i = 0; s.ok() && i < num; i++) {
WriteBatch batch;
batch.Put("a", Value(100, &value_storage));
s = db_->Write(WriteOptions(), &batch);
}
ASSERT_TRUE(!s.ok());
ASSERT_GE(env_.num_writable_file_errors_, 1);
env_.writable_file_error_ = false;
Reopen();
}
TEST(CorruptionTest, TableFile) {
Build(100);
DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
dbi->TEST_CompactMemTable();
dbi->TEST_CompactRange(0, NULL, NULL);
dbi->TEST_CompactRange(1, NULL, NULL);
Corrupt(kTableFile, 100, 1);
Check(99, 99);
}
TEST(CorruptionTest, TableFileIndexData) {
Build(10000); // Enough to build multiple Tables
DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
dbi->TEST_CompactMemTable();
Corrupt(kTableFile, -2000, 500);
Reopen();
Check(5000, 9999);
}
TEST(CorruptionTest, MissingDescriptor) {
Build(1000);
RepairDB();
Reopen();
Check(1000, 1000);
}
TEST(CorruptionTest, SequenceNumberRecovery) {
ASSERT_OK(db_->Put(WriteOptions(), "foo", "v1"));
ASSERT_OK(db_->Put(WriteOptions(), "foo", "v2"));
ASSERT_OK(db_->Put(WriteOptions(), "foo", "v3"));
ASSERT_OK(db_->Put(WriteOptions(), "foo", "v4"));
ASSERT_OK(db_->Put(WriteOptions(), "foo", "v5"));
RepairDB();
Reopen();
std::string v;
ASSERT_OK(db_->Get(ReadOptions(), "foo", &v));
ASSERT_EQ("v5", v);
// Write something. If sequence number was not recovered properly,
// it will be hidden by an earlier write.
ASSERT_OK(db_->Put(WriteOptions(), "foo", "v6"));
ASSERT_OK(db_->Get(ReadOptions(), "foo", &v));
ASSERT_EQ("v6", v);
Reopen();
ASSERT_OK(db_->Get(ReadOptions(), "foo", &v));
ASSERT_EQ("v6", v);
}
TEST(CorruptionTest, CorruptedDescriptor) {
ASSERT_OK(db_->Put(WriteOptions(), "foo", "hello"));
DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
dbi->TEST_CompactMemTable();
dbi->TEST_CompactRange(0, NULL, NULL);
Corrupt(kDescriptorFile, 0, 1000);
Status s = TryReopen();
ASSERT_TRUE(!s.ok());
RepairDB();
Reopen();
std::string v;
ASSERT_OK(db_->Get(ReadOptions(), "foo", &v));
ASSERT_EQ("hello", v);
}
TEST(CorruptionTest, CompactionInputError) {
Build(10);
DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
dbi->TEST_CompactMemTable();
const int last = config::kMaxMemCompactLevel;
ASSERT_EQ(1, Property("leveldb.num-files-at-level" + NumberToString(last)));
Corrupt(kTableFile, 100, 1);
Check(9, 9);
// Force compactions by writing lots of values
Build(10000);
Check(10000, 10000);
}
TEST(CorruptionTest, CompactionInputErrorParanoid) {
Options options;
options.paranoid_checks = true;
options.write_buffer_size = 1048576;
Reopen(&options);
DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
// Fill levels >= 1 so memtable compaction outputs to level 1
for (int level = 1; level < config::kNumLevels; level++) {
dbi->Put(WriteOptions(), "", "begin");
dbi->Put(WriteOptions(), "~", "end");
dbi->TEST_CompactMemTable();
}
Build(10);
dbi->TEST_CompactMemTable();
ASSERT_EQ(1, Property("leveldb.num-files-at-level0"));
Corrupt(kTableFile, 100, 1);
Check(9, 9);
// Write must eventually fail because of corrupted table
Status s;
std::string tmp1, tmp2;
for (int i = 0; i < 10000 && s.ok(); i++) {
s = db_->Put(WriteOptions(), Key(i, &tmp1), Value(i, &tmp2));
}
ASSERT_TRUE(!s.ok()) << "write did not fail in corrupted paranoid db";
}
TEST(CorruptionTest, UnrelatedKeys) {
Build(10);
DBImpl* dbi = reinterpret_cast<DBImpl*>(db_);
dbi->TEST_CompactMemTable();
Corrupt(kTableFile, 100, 1);
std::string tmp1, tmp2;
ASSERT_OK(db_->Put(WriteOptions(), Key(1000, &tmp1), Value(1000, &tmp2)));
std::string v;
ASSERT_OK(db_->Get(ReadOptions(), Key(1000, &tmp1), &v));
ASSERT_EQ(Value(1000, &tmp2).ToString(), v);
dbi->TEST_CompactMemTable();
ASSERT_OK(db_->Get(ReadOptions(), Key(1000, &tmp1), &v));
ASSERT_EQ(Value(1000, &tmp2).ToString(), v);
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

979
src/leveldb/db/db_bench.cc
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include "db/db_impl.h"
#include "db/version_set.h"
#include "leveldb/cache.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "leveldb/write_batch.h"
#include "port/port.h"
#include "util/crc32c.h"
#include "util/histogram.h"
#include "util/mutexlock.h"
#include "util/random.h"
#include "util/testutil.h"
// Comma-separated list of operations to run in the specified order
// Actual benchmarks:
// fillseq -- write N values in sequential key order in async mode
// fillrandom -- write N values in random key order in async mode
// overwrite -- overwrite N values in random key order in async mode
// fillsync -- write N/100 values in random key order in sync mode
// fill100K -- write N/1000 100K values in random order in async mode
// deleteseq -- delete N keys in sequential order
// deleterandom -- delete N keys in random order
// readseq -- read N times sequentially
// readreverse -- read N times in reverse order
// readrandom -- read N times in random order
// readmissing -- read N missing keys in random order
// readhot -- read N times in random order from 1% section of DB
// seekrandom -- N random seeks
// crc32c -- repeated crc32c of 4K of data
// acquireload -- load N*1000 times
// Meta operations:
// compact -- Compact the entire DB
// stats -- Print DB stats
// sstables -- Print sstable info
// heapprofile -- Dump a heap profile (if supported by this port)
static const char* FLAGS_benchmarks =
"fillseq,"
"fillsync,"
"fillrandom,"
"overwrite,"
"readrandom,"
"readrandom," // Extra run to allow previous compactions to quiesce
"readseq,"
"readreverse,"
"compact,"
"readrandom,"
"readseq,"
"readreverse,"
"fill100K,"
"crc32c,"
"snappycomp,"
"snappyuncomp,"
"acquireload,"
;
// Number of key/values to place in database
static int FLAGS_num = 1000000;
// Number of read operations to do. If negative, do FLAGS_num reads.
static int FLAGS_reads = -1;
// Number of concurrent threads to run.
static int FLAGS_threads = 1;
// Size of each value
static int FLAGS_value_size = 100;
// Arrange to generate values that shrink to this fraction of
// their original size after compression
static double FLAGS_compression_ratio = 0.5;
// Print histogram of operation timings
static bool FLAGS_histogram = false;
// Number of bytes to buffer in memtable before compacting
// (initialized to default value by "main")
static int FLAGS_write_buffer_size = 0;
// Number of bytes to use as a cache of uncompressed data.
// Negative means use default settings.
static int FLAGS_cache_size = -1;
// Maximum number of files to keep open at the same time (use default if == 0)
static int FLAGS_open_files = 0;
// Bloom filter bits per key.
// Negative means use default settings.
static int FLAGS_bloom_bits = -1;
// If true, do not destroy the existing database. If you set this
// flag and also specify a benchmark that wants a fresh database, that
// benchmark will fail.
static bool FLAGS_use_existing_db = false;
// Use the db with the following name.
static const char* FLAGS_db = NULL;
namespace leveldb {
namespace {
// Helper for quickly generating random data.
class RandomGenerator {
private:
std::string data_;
int pos_;
public:
RandomGenerator() {
// We use a limited amount of data over and over again and ensure
// that it is larger than the compression window (32KB), and also
// large enough to serve all typical value sizes we want to write.
Random rnd(301);
std::string piece;
while (data_.size() < 1048576) {
// Add a short fragment that is as compressible as specified
// by FLAGS_compression_ratio.
test::CompressibleString(&rnd, FLAGS_compression_ratio, 100, &piece);
data_.append(piece);
}
pos_ = 0;
}
Slice Generate(int len) {
if (pos_ + len > data_.size()) {
pos_ = 0;
assert(len < data_.size());
}
pos_ += len;
return Slice(data_.data() + pos_ - len, len);
}
};
static Slice TrimSpace(Slice s) {
int start = 0;
while (start < s.size() && isspace(s[start])) {
start++;
}
int limit = s.size();
while (limit > start && isspace(s[limit-1])) {
limit--;
}
return Slice(s.data() + start, limit - start);
}
static void AppendWithSpace(std::string* str, Slice msg) {
if (msg.empty()) return;
if (!str->empty()) {
str->push_back(' ');
}
str->append(msg.data(), msg.size());
}
class Stats {
private:
double start_;
double finish_;
double seconds_;
int done_;
int next_report_;
int64_t bytes_;
double last_op_finish_;
Histogram hist_;
std::string message_;
public:
Stats() { Start(); }
void Start() {
next_report_ = 100;
last_op_finish_ = start_;
hist_.Clear();
done_ = 0;
bytes_ = 0;
seconds_ = 0;
start_ = Env::Default()->NowMicros();
finish_ = start_;
message_.clear();
}
void Merge(const Stats& other) {
hist_.Merge(other.hist_);
done_ += other.done_;
bytes_ += other.bytes_;
seconds_ += other.seconds_;
if (other.start_ < start_) start_ = other.start_;
if (other.finish_ > finish_) finish_ = other.finish_;
// Just keep the messages from one thread
if (message_.empty()) message_ = other.message_;
}
void Stop() {
finish_ = Env::Default()->NowMicros();
seconds_ = (finish_ - start_) * 1e-6;
}
void AddMessage(Slice msg) {
AppendWithSpace(&message_, msg);
}
void FinishedSingleOp() {
if (FLAGS_histogram) {
double now = Env::Default()->NowMicros();
double micros = now - last_op_finish_;
hist_.Add(micros);
if (micros > 20000) {
fprintf(stderr, "long op: %.1f micros%30s\r", micros, "");
fflush(stderr);
}
last_op_finish_ = now;
}
done_++;
if (done_ >= next_report_) {
if (next_report_ < 1000) next_report_ += 100;
else if (next_report_ < 5000) next_report_ += 500;
else if (next_report_ < 10000) next_report_ += 1000;
else if (next_report_ < 50000) next_report_ += 5000;
else if (next_report_ < 100000) next_report_ += 10000;
else if (next_report_ < 500000) next_report_ += 50000;
else next_report_ += 100000;
fprintf(stderr, "... finished %d ops%30s\r", done_, "");
fflush(stderr);
}
}
void AddBytes(int64_t n) {
bytes_ += n;
}
void Report(const Slice& name) {
// Pretend at least one op was done in case we are running a benchmark
// that does not call FinishedSingleOp().
if (done_ < 1) done_ = 1;
std::string extra;
if (bytes_ > 0) {
// Rate is computed on actual elapsed time, not the sum of per-thread
// elapsed times.
double elapsed = (finish_ - start_) * 1e-6;
char rate[100];
snprintf(rate, sizeof(rate), "%6.1f MB/s",
(bytes_ / 1048576.0) / elapsed);
extra = rate;
}
AppendWithSpace(&extra, message_);
fprintf(stdout, "%-12s : %11.3f micros/op;%s%s\n",
name.ToString().c_str(),
seconds_ * 1e6 / done_,
(extra.empty() ? "" : " "),
extra.c_str());
if (FLAGS_histogram) {
fprintf(stdout, "Microseconds per op:\n%s\n", hist_.ToString().c_str());
}
fflush(stdout);
}
};
// State shared by all concurrent executions of the same benchmark.
struct SharedState {
port::Mutex mu;
port::CondVar cv;
int total;
// Each thread goes through the following states:
// (1) initializing
// (2) waiting for others to be initialized
// (3) running
// (4) done
int num_initialized;
int num_done;
bool start;
SharedState() : cv(&mu) { }
};
// Per-thread state for concurrent executions of the same benchmark.
struct ThreadState {
int tid; // 0..n-1 when running in n threads
Random rand; // Has different seeds for different threads
Stats stats;
SharedState* shared;
ThreadState(int index)
: tid(index),
rand(1000 + index) {
}
};
} // namespace
class Benchmark {
private:
Cache* cache_;
const FilterPolicy* filter_policy_;
DB* db_;
int num_;
int value_size_;
int entries_per_batch_;
WriteOptions write_options_;
int reads_;
int heap_counter_;
void PrintHeader() {
const int kKeySize = 16;
PrintEnvironment();
fprintf(stdout, "Keys: %d bytes each\n", kKeySize);
fprintf(stdout, "Values: %d bytes each (%d bytes after compression)\n",
FLAGS_value_size,
static_cast<int>(FLAGS_value_size * FLAGS_compression_ratio + 0.5));
fprintf(stdout, "Entries: %d\n", num_);
fprintf(stdout, "RawSize: %.1f MB (estimated)\n",
((static_cast<int64_t>(kKeySize + FLAGS_value_size) * num_)
/ 1048576.0));
fprintf(stdout, "FileSize: %.1f MB (estimated)\n",
(((kKeySize + FLAGS_value_size * FLAGS_compression_ratio) * num_)
/ 1048576.0));
PrintWarnings();
fprintf(stdout, "------------------------------------------------\n");
}
void PrintWarnings() {
#if defined(__GNUC__) && !defined(__OPTIMIZE__)
fprintf(stdout,
"WARNING: Optimization is disabled: benchmarks unnecessarily slow\n"
);
#endif
#ifndef NDEBUG
fprintf(stdout,
"WARNING: Assertions are enabled; benchmarks unnecessarily slow\n");
#endif
// See if snappy is working by attempting to compress a compressible string
const char text[] = "yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy";
std::string compressed;
if (!port::Snappy_Compress(text, sizeof(text), &compressed)) {
fprintf(stdout, "WARNING: Snappy compression is not enabled\n");
} else if (compressed.size() >= sizeof(text)) {
fprintf(stdout, "WARNING: Snappy compression is not effective\n");
}
}
void PrintEnvironment() {
fprintf(stderr, "LevelDB: version %d.%d\n",
kMajorVersion, kMinorVersion);
#if defined(__linux)
time_t now = time(NULL);
fprintf(stderr, "Date: %s", ctime(&now)); // ctime() adds newline
FILE* cpuinfo = fopen("/proc/cpuinfo", "r");
if (cpuinfo != NULL) {
char line[1000];
int num_cpus = 0;
std::string cpu_type;
std::string cache_size;
while (fgets(line, sizeof(line), cpuinfo) != NULL) {
const char* sep = strchr(line, ':');
if (sep == NULL) {
continue;
}
Slice key = TrimSpace(Slice(line, sep - 1 - line));
Slice val = TrimSpace(Slice(sep + 1));
if (key == "model name") {
++num_cpus;
cpu_type = val.ToString();
} else if (key == "cache size") {
cache_size = val.ToString();
}
}
fclose(cpuinfo);
fprintf(stderr, "CPU: %d * %s\n", num_cpus, cpu_type.c_str());
fprintf(stderr, "CPUCache: %s\n", cache_size.c_str());
}
#endif
}
public:
Benchmark()
: cache_(FLAGS_cache_size >= 0 ? NewLRUCache(FLAGS_cache_size) : NULL),
filter_policy_(FLAGS_bloom_bits >= 0
? NewBloomFilterPolicy(FLAGS_bloom_bits)
: NULL),
db_(NULL),
num_(FLAGS_num),
value_size_(FLAGS_value_size),
entries_per_batch_(1),
reads_(FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads),
heap_counter_(0) {
std::vector<std::string> files;
Env::Default()->GetChildren(FLAGS_db, &files);
for (int i = 0; i < files.size(); i++) {
if (Slice(files[i]).starts_with("heap-")) {
Env::Default()->DeleteFile(std::string(FLAGS_db) + "/" + files[i]);
}
}
if (!FLAGS_use_existing_db) {
DestroyDB(FLAGS_db, Options());
}
}
~Benchmark() {
delete db_;
delete cache_;
delete filter_policy_;
}
void Run() {
PrintHeader();
Open();
const char* benchmarks = FLAGS_benchmarks;
while (benchmarks != NULL) {
const char* sep = strchr(benchmarks, ',');
Slice name;
if (sep == NULL) {
name = benchmarks;
benchmarks = NULL;
} else {
name = Slice(benchmarks, sep - benchmarks);
benchmarks = sep + 1;
}
// Reset parameters that may be overriddden bwlow
num_ = FLAGS_num;
reads_ = (FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads);
value_size_ = FLAGS_value_size;
entries_per_batch_ = 1;
write_options_ = WriteOptions();
void (Benchmark::*method)(ThreadState*) = NULL;
bool fresh_db = false;
int num_threads = FLAGS_threads;
if (name == Slice("fillseq")) {
fresh_db = true;
method = &Benchmark::WriteSeq;
} else if (name == Slice("fillbatch")) {
fresh_db = true;
entries_per_batch_ = 1000;
method = &Benchmark::WriteSeq;
} else if (name == Slice("fillrandom")) {
fresh_db = true;
method = &Benchmark::WriteRandom;
} else if (name == Slice("overwrite")) {
fresh_db = false;
method = &Benchmark::WriteRandom;
} else if (name == Slice("fillsync")) {
fresh_db = true;
num_ /= 1000;
write_options_.sync = true;
method = &Benchmark::WriteRandom;
} else if (name == Slice("fill100K")) {
fresh_db = true;
num_ /= 1000;
value_size_ = 100 * 1000;
method = &Benchmark::WriteRandom;
} else if (name == Slice("readseq")) {
method = &Benchmark::ReadSequential;
} else if (name == Slice("readreverse")) {
method = &Benchmark::ReadReverse;
} else if (name == Slice("readrandom")) {
method = &Benchmark::ReadRandom;
} else if (name == Slice("readmissing")) {
method = &Benchmark::ReadMissing;
} else if (name == Slice("seekrandom")) {
method = &Benchmark::SeekRandom;
} else if (name == Slice("readhot")) {
method = &Benchmark::ReadHot;
} else if (name == Slice("readrandomsmall")) {
reads_ /= 1000;
method = &Benchmark::ReadRandom;
} else if (name == Slice("deleteseq")) {
method = &Benchmark::DeleteSeq;
} else if (name == Slice("deleterandom")) {
method = &Benchmark::DeleteRandom;
} else if (name == Slice("readwhilewriting")) {
num_threads++; // Add extra thread for writing
method = &Benchmark::ReadWhileWriting;
} else if (name == Slice("compact")) {
method = &Benchmark::Compact;
} else if (name == Slice("crc32c")) {
method = &Benchmark::Crc32c;
} else if (name == Slice("acquireload")) {
method = &Benchmark::AcquireLoad;
} else if (name == Slice("snappycomp")) {
method = &Benchmark::SnappyCompress;
} else if (name == Slice("snappyuncomp")) {
method = &Benchmark::SnappyUncompress;
} else if (name == Slice("heapprofile")) {
HeapProfile();
} else if (name == Slice("stats")) {
PrintStats("leveldb.stats");
} else if (name == Slice("sstables")) {
PrintStats("leveldb.sstables");
} else {
if (name != Slice()) { // No error message for empty name
fprintf(stderr, "unknown benchmark '%s'\n", name.ToString().c_str());
}
}
if (fresh_db) {
if (FLAGS_use_existing_db) {
fprintf(stdout, "%-12s : skipped (--use_existing_db is true)\n",
name.ToString().c_str());
method = NULL;
} else {
delete db_;
db_ = NULL;
DestroyDB(FLAGS_db, Options());
Open();
}
}
if (method != NULL) {
RunBenchmark(num_threads, name, method);
}
}
}
private:
struct ThreadArg {
Benchmark* bm;
SharedState* shared;
ThreadState* thread;
void (Benchmark::*method)(ThreadState*);
};
static void ThreadBody(void* v) {
ThreadArg* arg = reinterpret_cast<ThreadArg*>(v);
SharedState* shared = arg->shared;
ThreadState* thread = arg->thread;
{
MutexLock l(&shared->mu);
shared->num_initialized++;
if (shared->num_initialized >= shared->total) {
shared->cv.SignalAll();
}
while (!shared->start) {
shared->cv.Wait();
}
}
thread->stats.Start();
(arg->bm->*(arg->method))(thread);
thread->stats.Stop();
{
MutexLock l(&shared->mu);
shared->num_done++;
if (shared->num_done >= shared->total) {
shared->cv.SignalAll();
}
}
}
void RunBenchmark(int n, Slice name,
void (Benchmark::*method)(ThreadState*)) {
SharedState shared;
shared.total = n;
shared.num_initialized = 0;
shared.num_done = 0;
shared.start = false;
ThreadArg* arg = new ThreadArg[n];
for (int i = 0; i < n; i++) {
arg[i].bm = this;
arg[i].method = method;
arg[i].shared = &shared;
arg[i].thread = new ThreadState(i);
arg[i].thread->shared = &shared;
Env::Default()->StartThread(ThreadBody, &arg[i]);
}
shared.mu.Lock();
while (shared.num_initialized < n) {
shared.cv.Wait();
}
shared.start = true;
shared.cv.SignalAll();
while (shared.num_done < n) {
shared.cv.Wait();
}
shared.mu.Unlock();
for (int i = 1; i < n; i++) {
arg[0].thread->stats.Merge(arg[i].thread->stats);
}
arg[0].thread->stats.Report(name);
for (int i = 0; i < n; i++) {
delete arg[i].thread;
}
delete[] arg;
}
void Crc32c(ThreadState* thread) {
// Checksum about 500MB of data total
const int size = 4096;
const char* label = "(4K per op)";
std::string data(size, 'x');
int64_t bytes = 0;
uint32_t crc = 0;
while (bytes < 500 * 1048576) {
crc = crc32c::Value(data.data(), size);
thread->stats.FinishedSingleOp();
bytes += size;
}
// Print so result is not dead
fprintf(stderr, "... crc=0x%x\r", static_cast<unsigned int>(crc));
thread->stats.AddBytes(bytes);
thread->stats.AddMessage(label);
}
void AcquireLoad(ThreadState* thread) {
int dummy;
port::AtomicPointer ap(&dummy);
int count = 0;
void *ptr = NULL;
thread->stats.AddMessage("(each op is 1000 loads)");
while (count < 100000) {
for (int i = 0; i < 1000; i++) {
ptr = ap.Acquire_Load();
}
count++;
thread->stats.FinishedSingleOp();
}
if (ptr == NULL) exit(1); // Disable unused variable warning.
}
void SnappyCompress(ThreadState* thread) {
RandomGenerator gen;
Slice input = gen.Generate(Options().block_size);
int64_t bytes = 0;
int64_t produced = 0;
bool ok = true;
std::string compressed;
while (ok && bytes < 1024 * 1048576) { // Compress 1G
ok = port::Snappy_Compress(input.data(), input.size(), &compressed);
produced += compressed.size();
bytes += input.size();
thread->stats.FinishedSingleOp();
}
if (!ok) {
thread->stats.AddMessage("(snappy failure)");
} else {
char buf[100];
snprintf(buf, sizeof(buf), "(output: %.1f%%)",
(produced * 100.0) / bytes);
thread->stats.AddMessage(buf);
thread->stats.AddBytes(bytes);
}
}
void SnappyUncompress(ThreadState* thread) {
RandomGenerator gen;
Slice input = gen.Generate(Options().block_size);
std::string compressed;
bool ok = port::Snappy_Compress(input.data(), input.size(), &compressed);
int64_t bytes = 0;
char* uncompressed = new char[input.size()];
while (ok && bytes < 1024 * 1048576) { // Compress 1G
ok = port::Snappy_Uncompress(compressed.data(), compressed.size(),
uncompressed);
bytes += input.size();
thread->stats.FinishedSingleOp();
}
delete[] uncompressed;
if (!ok) {
thread->stats.AddMessage("(snappy failure)");
} else {
thread->stats.AddBytes(bytes);
}
}
void Open() {
assert(db_ == NULL);
Options options;
options.create_if_missing = !FLAGS_use_existing_db;
options.block_cache = cache_;
options.write_buffer_size = FLAGS_write_buffer_size;
options.max_open_files = FLAGS_open_files;
options.filter_policy = filter_policy_;
Status s = DB::Open(options, FLAGS_db, &db_);
if (!s.ok()) {
fprintf(stderr, "open error: %s\n", s.ToString().c_str());
exit(1);
}
}
void WriteSeq(ThreadState* thread) {
DoWrite(thread, true);
}
void WriteRandom(ThreadState* thread) {
DoWrite(thread, false);
}
void DoWrite(ThreadState* thread, bool seq) {
if (num_ != FLAGS_num) {
char msg[100];
snprintf(msg, sizeof(msg), "(%d ops)", num_);
thread->stats.AddMessage(msg);
}
RandomGenerator gen;
WriteBatch batch;
Status s;
int64_t bytes = 0;
for (int i = 0; i < num_; i += entries_per_batch_) {
batch.Clear();
for (int j = 0; j < entries_per_batch_; j++) {
const int k = seq ? i+j : (thread->rand.Next() % FLAGS_num);
char key[100];
snprintf(key, sizeof(key), "%016d", k);
batch.Put(key, gen.Generate(value_size_));
bytes += value_size_ + strlen(key);
thread->stats.FinishedSingleOp();
}
s = db_->Write(write_options_, &batch);
if (!s.ok()) {
fprintf(stderr, "put error: %s\n", s.ToString().c_str());
exit(1);
}
}
thread->stats.AddBytes(bytes);
}
void ReadSequential(ThreadState* thread) {
Iterator* iter = db_->NewIterator(ReadOptions());
int i = 0;
int64_t bytes = 0;
for (iter->SeekToFirst(); i < reads_ && iter->Valid(); iter->Next()) {
bytes += iter->key().size() + iter->value().size();
thread->stats.FinishedSingleOp();
++i;
}
delete iter;
thread->stats.AddBytes(bytes);
}
void ReadReverse(ThreadState* thread) {
Iterator* iter = db_->NewIterator(ReadOptions());
int i = 0;
int64_t bytes = 0;
for (iter->SeekToLast(); i < reads_ && iter->Valid(); iter->Prev()) {
bytes += iter->key().size() + iter->value().size();
thread->stats.FinishedSingleOp();
++i;
}
delete iter;
thread->stats.AddBytes(bytes);
}
void ReadRandom(ThreadState* thread) {
ReadOptions options;
std::string value;
int found = 0;
for (int i = 0; i < reads_; i++) {
char key[100];
const int k = thread->rand.Next() % FLAGS_num;
snprintf(key, sizeof(key), "%016d", k);
if (db_->Get(options, key, &value).ok()) {
found++;
}
thread->stats.FinishedSingleOp();
}
char msg[100];
snprintf(msg, sizeof(msg), "(%d of %d found)", found, num_);
thread->stats.AddMessage(msg);
}
void ReadMissing(ThreadState* thread) {
ReadOptions options;
std::string value;
for (int i = 0; i < reads_; i++) {
char key[100];
const int k = thread->rand.Next() % FLAGS_num;
snprintf(key, sizeof(key), "%016d.", k);
db_->Get(options, key, &value);
thread->stats.FinishedSingleOp();
}
}
void ReadHot(ThreadState* thread) {
ReadOptions options;
std::string value;
const int range = (FLAGS_num + 99) / 100;
for (int i = 0; i < reads_; i++) {
char key[100];
const int k = thread->rand.Next() % range;
snprintf(key, sizeof(key), "%016d", k);
db_->Get(options, key, &value);
thread->stats.FinishedSingleOp();
}
}
void SeekRandom(ThreadState* thread) {
ReadOptions options;
std::string value;
int found = 0;
for (int i = 0; i < reads_; i++) {
Iterator* iter = db_->NewIterator(options);
char key[100];
const int k = thread->rand.Next() % FLAGS_num;
snprintf(key, sizeof(key), "%016d", k);
iter->Seek(key);
if (iter->Valid() && iter->key() == key) found++;
delete iter;
thread->stats.FinishedSingleOp();
}
char msg[100];
snprintf(msg, sizeof(msg), "(%d of %d found)", found, num_);
thread->stats.AddMessage(msg);
}
void DoDelete(ThreadState* thread, bool seq) {
RandomGenerator gen;
WriteBatch batch;
Status s;
for (int i = 0; i < num_; i += entries_per_batch_) {
batch.Clear();
for (int j = 0; j < entries_per_batch_; j++) {
const int k = seq ? i+j : (thread->rand.Next() % FLAGS_num);
char key[100];
snprintf(key, sizeof(key), "%016d", k);
batch.Delete(key);
thread->stats.FinishedSingleOp();
}
s = db_->Write(write_options_, &batch);
if (!s.ok()) {
fprintf(stderr, "del error: %s\n", s.ToString().c_str());
exit(1);
}
}
}
void DeleteSeq(ThreadState* thread) {
DoDelete(thread, true);
}
void DeleteRandom(ThreadState* thread) {
DoDelete(thread, false);
}
void ReadWhileWriting(ThreadState* thread) {
if (thread->tid > 0) {
ReadRandom(thread);
} else {
// Special thread that keeps writing until other threads are done.
RandomGenerator gen;
while (true) {
{
MutexLock l(&thread->shared->mu);
if (thread->shared->num_done + 1 >= thread->shared->num_initialized) {
// Other threads have finished
break;
}
}
const int k = thread->rand.Next() % FLAGS_num;
char key[100];
snprintf(key, sizeof(key), "%016d", k);
Status s = db_->Put(write_options_, key, gen.Generate(value_size_));
if (!s.ok()) {
fprintf(stderr, "put error: %s\n", s.ToString().c_str());
exit(1);
}
}
// Do not count any of the preceding work/delay in stats.
thread->stats.Start();
}
}
void Compact(ThreadState* thread) {
db_->CompactRange(NULL, NULL);
}
void PrintStats(const char* key) {
std::string stats;
if (!db_->GetProperty(key, &stats)) {
stats = "(failed)";
}
fprintf(stdout, "\n%s\n", stats.c_str());
}
static void WriteToFile(void* arg, const char* buf, int n) {
reinterpret_cast<WritableFile*>(arg)->Append(Slice(buf, n));
}
void HeapProfile() {
char fname[100];
snprintf(fname, sizeof(fname), "%s/heap-%04d", FLAGS_db, ++heap_counter_);
WritableFile* file;
Status s = Env::Default()->NewWritableFile(fname, &file);
if (!s.ok()) {
fprintf(stderr, "%s\n", s.ToString().c_str());
return;
}
bool ok = port::GetHeapProfile(WriteToFile, file);
delete file;
if (!ok) {
fprintf(stderr, "heap profiling not supported\n");
Env::Default()->DeleteFile(fname);
}
}
};
} // namespace leveldb
int main(int argc, char** argv) {
FLAGS_write_buffer_size = leveldb::Options().write_buffer_size;
FLAGS_open_files = leveldb::Options().max_open_files;
std::string default_db_path;
for (int i = 1; i < argc; i++) {
double d;
int n;
char junk;
if (leveldb::Slice(argv[i]).starts_with("--benchmarks=")) {
FLAGS_benchmarks = argv[i] + strlen("--benchmarks=");
} else if (sscanf(argv[i], "--compression_ratio=%lf%c", &d, &junk) == 1) {
FLAGS_compression_ratio = d;
} else if (sscanf(argv[i], "--histogram=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_histogram = n;
} else if (sscanf(argv[i], "--use_existing_db=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_use_existing_db = n;
} else if (sscanf(argv[i], "--num=%d%c", &n, &junk) == 1) {
FLAGS_num = n;
} else if (sscanf(argv[i], "--reads=%d%c", &n, &junk) == 1) {
FLAGS_reads = n;
} else if (sscanf(argv[i], "--threads=%d%c", &n, &junk) == 1) {
FLAGS_threads = n;
} else if (sscanf(argv[i], "--value_size=%d%c", &n, &junk) == 1) {
FLAGS_value_size = n;
} else if (sscanf(argv[i], "--write_buffer_size=%d%c", &n, &junk) == 1) {
FLAGS_write_buffer_size = n;
} else if (sscanf(argv[i], "--cache_size=%d%c", &n, &junk) == 1) {
FLAGS_cache_size = n;
} else if (sscanf(argv[i], "--bloom_bits=%d%c", &n, &junk) == 1) {
FLAGS_bloom_bits = n;
} else if (sscanf(argv[i], "--open_files=%d%c", &n, &junk) == 1) {
FLAGS_open_files = n;
} else if (strncmp(argv[i], "--db=", 5) == 0) {
FLAGS_db = argv[i] + 5;
} else {
fprintf(stderr, "Invalid flag '%s'\n", argv[i]);
exit(1);
}
}
// Choose a location for the test database if none given with --db=<path>
if (FLAGS_db == NULL) {
leveldb::Env::Default()->GetTestDirectory(&default_db_path);
default_db_path += "/dbbench";
FLAGS_db = default_db_path.c_str();
}
leveldb::Benchmark benchmark;
benchmark.Run();
return 0;
}

1467
src/leveldb/db/db_impl.cc
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202
src/leveldb/db/db_impl.h
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@ -1,202 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_DB_IMPL_H_
#define STORAGE_LEVELDB_DB_DB_IMPL_H_
#include <deque>
#include <set>
#include "db/dbformat.h"
#include "db/log_writer.h"
#include "db/snapshot.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "port/port.h"
#include "port/thread_annotations.h"
namespace leveldb {
class MemTable;
class TableCache;
class Version;
class VersionEdit;
class VersionSet;
class DBImpl : public DB {
public:
DBImpl(const Options& options, const std::string& dbname);
virtual ~DBImpl();
// Implementations of the DB interface
virtual Status Put(const WriteOptions&, const Slice& key, const Slice& value);
virtual Status Delete(const WriteOptions&, const Slice& key);
virtual Status Write(const WriteOptions& options, WriteBatch* updates);
virtual Status Get(const ReadOptions& options,
const Slice& key,
std::string* value);
virtual Iterator* NewIterator(const ReadOptions&);
virtual const Snapshot* GetSnapshot();
virtual void ReleaseSnapshot(const Snapshot* snapshot);
virtual bool GetProperty(const Slice& property, std::string* value);
virtual void GetApproximateSizes(const Range* range, int n, uint64_t* sizes);
virtual void CompactRange(const Slice* begin, const Slice* end);
// Extra methods (for testing) that are not in the public DB interface
// Compact any files in the named level that overlap [*begin,*end]
void TEST_CompactRange(int level, const Slice* begin, const Slice* end);
// Force current memtable contents to be compacted.
Status TEST_CompactMemTable();
// Return an internal iterator over the current state of the database.
// The keys of this iterator are internal keys (see format.h).
// The returned iterator should be deleted when no longer needed.
Iterator* TEST_NewInternalIterator();
// Return the maximum overlapping data (in bytes) at next level for any
// file at a level >= 1.
int64_t TEST_MaxNextLevelOverlappingBytes();
private:
friend class DB;
struct CompactionState;
struct Writer;
Iterator* NewInternalIterator(const ReadOptions&,
SequenceNumber* latest_snapshot);
Status NewDB();
// Recover the descriptor from persistent storage. May do a significant
// amount of work to recover recently logged updates. Any changes to
// be made to the descriptor are added to *edit.
Status Recover(VersionEdit* edit) EXCLUSIVE_LOCKS_REQUIRED(mutex_);
void MaybeIgnoreError(Status* s) const;
// Delete any unneeded files and stale in-memory entries.
void DeleteObsoleteFiles();
// Compact the in-memory write buffer to disk. Switches to a new
// log-file/memtable and writes a new descriptor iff successful.
Status CompactMemTable()
EXCLUSIVE_LOCKS_REQUIRED(mutex_);
Status RecoverLogFile(uint64_t log_number,
VersionEdit* edit,
SequenceNumber* max_sequence)
EXCLUSIVE_LOCKS_REQUIRED(mutex_);
Status WriteLevel0Table(MemTable* mem, VersionEdit* edit, Version* base)
EXCLUSIVE_LOCKS_REQUIRED(mutex_);
Status MakeRoomForWrite(bool force /* compact even if there is room? */)
EXCLUSIVE_LOCKS_REQUIRED(mutex_);
WriteBatch* BuildBatchGroup(Writer** last_writer);
void MaybeScheduleCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
static void BGWork(void* db);
void BackgroundCall();
Status BackgroundCompaction() EXCLUSIVE_LOCKS_REQUIRED(mutex_);
void CleanupCompaction(CompactionState* compact)
EXCLUSIVE_LOCKS_REQUIRED(mutex_);
Status DoCompactionWork(CompactionState* compact)
EXCLUSIVE_LOCKS_REQUIRED(mutex_);
Status OpenCompactionOutputFile(CompactionState* compact);
Status FinishCompactionOutputFile(CompactionState* compact, Iterator* input);
Status InstallCompactionResults(CompactionState* compact)
EXCLUSIVE_LOCKS_REQUIRED(mutex_);
// Constant after construction
Env* const env_;
const InternalKeyComparator internal_comparator_;
const InternalFilterPolicy internal_filter_policy_;
const Options options_; // options_.comparator == &internal_comparator_
bool owns_info_log_;
bool owns_cache_;
const std::string dbname_;
// table_cache_ provides its own synchronization
TableCache* table_cache_;
// Lock over the persistent DB state. Non-NULL iff successfully acquired.
FileLock* db_lock_;
// State below is protected by mutex_
port::Mutex mutex_;
port::AtomicPointer shutting_down_;
port::CondVar bg_cv_; // Signalled when background work finishes
MemTable* mem_;
MemTable* imm_; // Memtable being compacted
port::AtomicPointer has_imm_; // So bg thread can detect non-NULL imm_
WritableFile* logfile_;
uint64_t logfile_number_;
log::Writer* log_;
// Queue of writers.
std::deque<Writer*> writers_;
WriteBatch* tmp_batch_;
SnapshotList snapshots_;
// Set of table files to protect from deletion because they are
// part of ongoing compactions.
std::set<uint64_t> pending_outputs_;
// Has a background compaction been scheduled or is running?
bool bg_compaction_scheduled_;
// Information for a manual compaction
struct ManualCompaction {
int level;
bool done;
const InternalKey* begin; // NULL means beginning of key range
const InternalKey* end; // NULL means end of key range
InternalKey tmp_storage; // Used to keep track of compaction progress
};
ManualCompaction* manual_compaction_;
VersionSet* versions_;
// Have we encountered a background error in paranoid mode?
Status bg_error_;
// Per level compaction stats. stats_[level] stores the stats for
// compactions that produced data for the specified "level".
struct CompactionStats {
int64_t micros;
int64_t bytes_read;
int64_t bytes_written;
CompactionStats() : micros(0), bytes_read(0), bytes_written(0) { }
void Add(const CompactionStats& c) {
this->micros += c.micros;
this->bytes_read += c.bytes_read;
this->bytes_written += c.bytes_written;
}
};
CompactionStats stats_[config::kNumLevels];
// No copying allowed
DBImpl(const DBImpl&);
void operator=(const DBImpl&);
const Comparator* user_comparator() const {
return internal_comparator_.user_comparator();
}
};
// Sanitize db options. The caller should delete result.info_log if
// it is not equal to src.info_log.
extern Options SanitizeOptions(const std::string& db,
const InternalKeyComparator* icmp,
const InternalFilterPolicy* ipolicy,
const Options& src);
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_DB_IMPL_H_

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src/leveldb/db/db_iter.cc
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/db_iter.h"
#include "db/filename.h"
#include "db/dbformat.h"
#include "leveldb/env.h"
#include "leveldb/iterator.h"
#include "port/port.h"
#include "util/logging.h"
#include "util/mutexlock.h"
namespace leveldb {
#if 0
static void DumpInternalIter(Iterator* iter) {
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
ParsedInternalKey k;
if (!ParseInternalKey(iter->key(), &k)) {
fprintf(stderr, "Corrupt '%s'\n", EscapeString(iter->key()).c_str());
} else {
fprintf(stderr, "@ '%s'\n", k.DebugString().c_str());
}
}
}
#endif
namespace {
// Memtables and sstables that make the DB representation contain
// (userkey,seq,type) => uservalue entries. DBIter
// combines multiple entries for the same userkey found in the DB
// representation into a single entry while accounting for sequence
// numbers, deletion markers, overwrites, etc.
class DBIter: public Iterator {
public:
// Which direction is the iterator currently moving?
// (1) When moving forward, the internal iterator is positioned at
// the exact entry that yields this->key(), this->value()
// (2) When moving backwards, the internal iterator is positioned
// just before all entries whose user key == this->key().
enum Direction {
kForward,
kReverse
};
DBIter(const std::string* dbname, Env* env,
const Comparator* cmp, Iterator* iter, SequenceNumber s)
: dbname_(dbname),
env_(env),
user_comparator_(cmp),
iter_(iter),
sequence_(s),
direction_(kForward),
valid_(false) {
}
virtual ~DBIter() {
delete iter_;
}
virtual bool Valid() const { return valid_; }
virtual Slice key() const {
assert(valid_);
return (direction_ == kForward) ? ExtractUserKey(iter_->key()) : saved_key_;
}
virtual Slice value() const {
assert(valid_);
return (direction_ == kForward) ? iter_->value() : saved_value_;
}
virtual Status status() const {
if (status_.ok()) {
return iter_->status();
} else {
return status_;
}
}
virtual void Next();
virtual void Prev();
virtual void Seek(const Slice& target);
virtual void SeekToFirst();
virtual void SeekToLast();
private:
void FindNextUserEntry(bool skipping, std::string* skip);
void FindPrevUserEntry();
bool ParseKey(ParsedInternalKey* key);
inline void SaveKey(const Slice& k, std::string* dst) {
dst->assign(k.data(), k.size());
}
inline void ClearSavedValue() {
if (saved_value_.capacity() > 1048576) {
std::string empty;
swap(empty, saved_value_);
} else {
saved_value_.clear();
}
}
const std::string* const dbname_;
Env* const env_;
const Comparator* const user_comparator_;
Iterator* const iter_;
SequenceNumber const sequence_;
Status status_;
std::string saved_key_; // == current key when direction_==kReverse
std::string saved_value_; // == current raw value when direction_==kReverse
Direction direction_;
bool valid_;
// No copying allowed
DBIter(const DBIter&);
void operator=(const DBIter&);
};
inline bool DBIter::ParseKey(ParsedInternalKey* ikey) {
if (!ParseInternalKey(iter_->key(), ikey)) {
status_ = Status::Corruption("corrupted internal key in DBIter");
return false;
} else {
return true;
}
}
void DBIter::Next() {
assert(valid_);
if (direction_ == kReverse) { // Switch directions?
direction_ = kForward;
// iter_ is pointing just before the entries for this->key(),
// so advance into the range of entries for this->key() and then
// use the normal skipping code below.
if (!iter_->Valid()) {
iter_->SeekToFirst();
} else {
iter_->Next();
}
if (!iter_->Valid()) {
valid_ = false;
saved_key_.clear();
return;
}
}
// Temporarily use saved_key_ as storage for key to skip.
std::string* skip = &saved_key_;
SaveKey(ExtractUserKey(iter_->key()), skip);
FindNextUserEntry(true, skip);
}
void DBIter::FindNextUserEntry(bool skipping, std::string* skip) {
// Loop until we hit an acceptable entry to yield
assert(iter_->Valid());
assert(direction_ == kForward);
do {
ParsedInternalKey ikey;
if (ParseKey(&ikey) && ikey.sequence <= sequence_) {
switch (ikey.type) {
case kTypeDeletion:
// Arrange to skip all upcoming entries for this key since
// they are hidden by this deletion.
SaveKey(ikey.user_key, skip);
skipping = true;
break;
case kTypeValue:
if (skipping &&
user_comparator_->Compare(ikey.user_key, *skip) <= 0) {
// Entry hidden
} else {
valid_ = true;
saved_key_.clear();
return;
}
break;
}
}
iter_->Next();
} while (iter_->Valid());
saved_key_.clear();
valid_ = false;
}
void DBIter::Prev() {
assert(valid_);
if (direction_ == kForward) { // Switch directions?
// iter_ is pointing at the current entry. Scan backwards until
// the key changes so we can use the normal reverse scanning code.
assert(iter_->Valid()); // Otherwise valid_ would have been false
SaveKey(ExtractUserKey(iter_->key()), &saved_key_);
while (true) {
iter_->Prev();
if (!iter_->Valid()) {
valid_ = false;
saved_key_.clear();
ClearSavedValue();
return;
}
if (user_comparator_->Compare(ExtractUserKey(iter_->key()),
saved_key_) < 0) {
break;
}
}
direction_ = kReverse;
}
FindPrevUserEntry();
}
void DBIter::FindPrevUserEntry() {
assert(direction_ == kReverse);
ValueType value_type = kTypeDeletion;
if (iter_->Valid()) {
do {
ParsedInternalKey ikey;
if (ParseKey(&ikey) && ikey.sequence <= sequence_) {
if ((value_type != kTypeDeletion) &&
user_comparator_->Compare(ikey.user_key, saved_key_) < 0) {
// We encountered a non-deleted value in entries for previous keys,
break;
}
value_type = ikey.type;
if (value_type == kTypeDeletion) {
saved_key_.clear();
ClearSavedValue();
} else {
Slice raw_value = iter_->value();
if (saved_value_.capacity() > raw_value.size() + 1048576) {
std::string empty;
swap(empty, saved_value_);
}
SaveKey(ExtractUserKey(iter_->key()), &saved_key_);
saved_value_.assign(raw_value.data(), raw_value.size());
}
}
iter_->Prev();
} while (iter_->Valid());
}
if (value_type == kTypeDeletion) {
// End
valid_ = false;
saved_key_.clear();
ClearSavedValue();
direction_ = kForward;
} else {
valid_ = true;
}
}
void DBIter::Seek(const Slice& target) {
direction_ = kForward;
ClearSavedValue();
saved_key_.clear();
AppendInternalKey(
&saved_key_, ParsedInternalKey(target, sequence_, kValueTypeForSeek));
iter_->Seek(saved_key_);
if (iter_->Valid()) {
FindNextUserEntry(false, &saved_key_ /* temporary storage */);
} else {
valid_ = false;
}
}
void DBIter::SeekToFirst() {
direction_ = kForward;
ClearSavedValue();
iter_->SeekToFirst();
if (iter_->Valid()) {
FindNextUserEntry(false, &saved_key_ /* temporary storage */);
} else {
valid_ = false;
}
}
void DBIter::SeekToLast() {
direction_ = kReverse;
ClearSavedValue();
iter_->SeekToLast();
FindPrevUserEntry();
}
} // anonymous namespace
Iterator* NewDBIterator(
const std::string* dbname,
Env* env,
const Comparator* user_key_comparator,
Iterator* internal_iter,
const SequenceNumber& sequence) {
return new DBIter(dbname, env, user_key_comparator, internal_iter, sequence);
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_DB_ITER_H_
#define STORAGE_LEVELDB_DB_DB_ITER_H_
#include <stdint.h>
#include "leveldb/db.h"
#include "db/dbformat.h"
namespace leveldb {
// Return a new iterator that converts internal keys (yielded by
// "*internal_iter") that were live at the specified "sequence" number
// into appropriate user keys.
extern Iterator* NewDBIterator(
const std::string* dbname,
Env* env,
const Comparator* user_key_comparator,
Iterator* internal_iter,
const SequenceNumber& sequence);
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_DB_ITER_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include <stdio.h>
#include "db/dbformat.h"
#include "port/port.h"
#include "util/coding.h"
namespace leveldb {
static uint64_t PackSequenceAndType(uint64_t seq, ValueType t) {
assert(seq <= kMaxSequenceNumber);
assert(t <= kValueTypeForSeek);
return (seq << 8) | t;
}
void AppendInternalKey(std::string* result, const ParsedInternalKey& key) {
result->append(key.user_key.data(), key.user_key.size());
PutFixed64(result, PackSequenceAndType(key.sequence, key.type));
}
std::string ParsedInternalKey::DebugString() const {
char buf[50];
snprintf(buf, sizeof(buf), "' @ %llu : %d",
(unsigned long long) sequence,
int(type));
std::string result = "'";
result += user_key.ToString();
result += buf;
return result;
}
std::string InternalKey::DebugString() const {
std::string result;
ParsedInternalKey parsed;
if (ParseInternalKey(rep_, &parsed)) {
result = parsed.DebugString();
} else {
result = "(bad)";
result.append(EscapeString(rep_));
}
return result;
}
const char* InternalKeyComparator::Name() const {
return "leveldb.InternalKeyComparator";
}
int InternalKeyComparator::Compare(const Slice& akey, const Slice& bkey) const {
// Order by:
// increasing user key (according to user-supplied comparator)
// decreasing sequence number
// decreasing type (though sequence# should be enough to disambiguate)
int r = user_comparator_->Compare(ExtractUserKey(akey), ExtractUserKey(bkey));
if (r == 0) {
const uint64_t anum = DecodeFixed64(akey.data() + akey.size() - 8);
const uint64_t bnum = DecodeFixed64(bkey.data() + bkey.size() - 8);
if (anum > bnum) {
r = -1;
} else if (anum < bnum) {
r = +1;
}
}
return r;
}
void InternalKeyComparator::FindShortestSeparator(
std::string* start,
const Slice& limit) const {
// Attempt to shorten the user portion of the key
Slice user_start = ExtractUserKey(*start);
Slice user_limit = ExtractUserKey(limit);
std::string tmp(user_start.data(), user_start.size());
user_comparator_->FindShortestSeparator(&tmp, user_limit);
if (tmp.size() < user_start.size() &&
user_comparator_->Compare(user_start, tmp) < 0) {
// User key has become shorter physically, but larger logically.
// Tack on the earliest possible number to the shortened user key.
PutFixed64(&tmp, PackSequenceAndType(kMaxSequenceNumber,kValueTypeForSeek));
assert(this->Compare(*start, tmp) < 0);
assert(this->Compare(tmp, limit) < 0);
start->swap(tmp);
}
}
void InternalKeyComparator::FindShortSuccessor(std::string* key) const {
Slice user_key = ExtractUserKey(*key);
std::string tmp(user_key.data(), user_key.size());
user_comparator_->FindShortSuccessor(&tmp);
if (tmp.size() < user_key.size() &&
user_comparator_->Compare(user_key, tmp) < 0) {
// User key has become shorter physically, but larger logically.
// Tack on the earliest possible number to the shortened user key.
PutFixed64(&tmp, PackSequenceAndType(kMaxSequenceNumber,kValueTypeForSeek));
assert(this->Compare(*key, tmp) < 0);
key->swap(tmp);
}
}
const char* InternalFilterPolicy::Name() const {
return user_policy_->Name();
}
void InternalFilterPolicy::CreateFilter(const Slice* keys, int n,
std::string* dst) const {
// We rely on the fact that the code in table.cc does not mind us
// adjusting keys[].
Slice* mkey = const_cast<Slice*>(keys);
for (int i = 0; i < n; i++) {
mkey[i] = ExtractUserKey(keys[i]);
// TODO(sanjay): Suppress dups?
}
user_policy_->CreateFilter(keys, n, dst);
}
bool InternalFilterPolicy::KeyMayMatch(const Slice& key, const Slice& f) const {
return user_policy_->KeyMayMatch(ExtractUserKey(key), f);
}
LookupKey::LookupKey(const Slice& user_key, SequenceNumber s) {
size_t usize = user_key.size();
size_t needed = usize + 13; // A conservative estimate
char* dst;
if (needed <= sizeof(space_)) {
dst = space_;
} else {
dst = new char[needed];
}
start_ = dst;
dst = EncodeVarint32(dst, usize + 8);
kstart_ = dst;
memcpy(dst, user_key.data(), usize);
dst += usize;
EncodeFixed64(dst, PackSequenceAndType(s, kValueTypeForSeek));
dst += 8;
end_ = dst;
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_FORMAT_H_
#define STORAGE_LEVELDB_DB_FORMAT_H_
#include <stdio.h>
#include "leveldb/comparator.h"
#include "leveldb/db.h"
#include "leveldb/filter_policy.h"
#include "leveldb/slice.h"
#include "leveldb/table_builder.h"
#include "util/coding.h"
#include "util/logging.h"
namespace leveldb {
// Grouping of constants. We may want to make some of these
// parameters set via options.
namespace config {
static const int kNumLevels = 7;
// Level-0 compaction is started when we hit this many files.
static const int kL0_CompactionTrigger = 4;
// Soft limit on number of level-0 files. We slow down writes at this point.
static const int kL0_SlowdownWritesTrigger = 8;
// Maximum number of level-0 files. We stop writes at this point.
static const int kL0_StopWritesTrigger = 12;
// Maximum level to which a new compacted memtable is pushed if it
// does not create overlap. We try to push to level 2 to avoid the
// relatively expensive level 0=>1 compactions and to avoid some
// expensive manifest file operations. We do not push all the way to
// the largest level since that can generate a lot of wasted disk
// space if the same key space is being repeatedly overwritten.
static const int kMaxMemCompactLevel = 2;
} // namespace config
class InternalKey;
// Value types encoded as the last component of internal keys.
// DO NOT CHANGE THESE ENUM VALUES: they are embedded in the on-disk
// data structures.
enum ValueType {
kTypeDeletion = 0x0,
kTypeValue = 0x1
};
// kValueTypeForSeek defines the ValueType that should be passed when
// constructing a ParsedInternalKey object for seeking to a particular
// sequence number (since we sort sequence numbers in decreasing order
// and the value type is embedded as the low 8 bits in the sequence
// number in internal keys, we need to use the highest-numbered
// ValueType, not the lowest).
static const ValueType kValueTypeForSeek = kTypeValue;
typedef uint64_t SequenceNumber;
// We leave eight bits empty at the bottom so a type and sequence#
// can be packed together into 64-bits.
static const SequenceNumber kMaxSequenceNumber =
((0x1ull << 56) - 1);
struct ParsedInternalKey {
Slice user_key;
SequenceNumber sequence;
ValueType type;
ParsedInternalKey() { } // Intentionally left uninitialized (for speed)
ParsedInternalKey(const Slice& u, const SequenceNumber& seq, ValueType t)
: user_key(u), sequence(seq), type(t) { }
std::string DebugString() const;
};
// Return the length of the encoding of "key".
inline size_t InternalKeyEncodingLength(const ParsedInternalKey& key) {
return key.user_key.size() + 8;
}
// Append the serialization of "key" to *result.
extern void AppendInternalKey(std::string* result,
const ParsedInternalKey& key);
// Attempt to parse an internal key from "internal_key". On success,
// stores the parsed data in "*result", and returns true.
//
// On error, returns false, leaves "*result" in an undefined state.
extern bool ParseInternalKey(const Slice& internal_key,
ParsedInternalKey* result);
// Returns the user key portion of an internal key.
inline Slice ExtractUserKey(const Slice& internal_key) {
assert(internal_key.size() >= 8);
return Slice(internal_key.data(), internal_key.size() - 8);
}
inline ValueType ExtractValueType(const Slice& internal_key) {
assert(internal_key.size() >= 8);
const size_t n = internal_key.size();
uint64_t num = DecodeFixed64(internal_key.data() + n - 8);
unsigned char c = num & 0xff;
return static_cast<ValueType>(c);
}
// A comparator for internal keys that uses a specified comparator for
// the user key portion and breaks ties by decreasing sequence number.
class InternalKeyComparator : public Comparator {
private:
const Comparator* user_comparator_;
public:
explicit InternalKeyComparator(const Comparator* c) : user_comparator_(c) { }
virtual const char* Name() const;
virtual int Compare(const Slice& a, const Slice& b) const;
virtual void FindShortestSeparator(
std::string* start,
const Slice& limit) const;
virtual void FindShortSuccessor(std::string* key) const;
const Comparator* user_comparator() const { return user_comparator_; }
int Compare(const InternalKey& a, const InternalKey& b) const;
};
// Filter policy wrapper that converts from internal keys to user keys
class InternalFilterPolicy : public FilterPolicy {
private:
const FilterPolicy* const user_policy_;
public:
explicit InternalFilterPolicy(const FilterPolicy* p) : user_policy_(p) { }
virtual const char* Name() const;
virtual void CreateFilter(const Slice* keys, int n, std::string* dst) const;
virtual bool KeyMayMatch(const Slice& key, const Slice& filter) const;
};
// Modules in this directory should keep internal keys wrapped inside
// the following class instead of plain strings so that we do not
// incorrectly use string comparisons instead of an InternalKeyComparator.
class InternalKey {
private:
std::string rep_;
public:
InternalKey() { } // Leave rep_ as empty to indicate it is invalid
InternalKey(const Slice& user_key, SequenceNumber s, ValueType t) {
AppendInternalKey(&rep_, ParsedInternalKey(user_key, s, t));
}
void DecodeFrom(const Slice& s) { rep_.assign(s.data(), s.size()); }
Slice Encode() const {
assert(!rep_.empty());
return rep_;
}
Slice user_key() const { return ExtractUserKey(rep_); }
void SetFrom(const ParsedInternalKey& p) {
rep_.clear();
AppendInternalKey(&rep_, p);
}
void Clear() { rep_.clear(); }
std::string DebugString() const;
};
inline int InternalKeyComparator::Compare(
const InternalKey& a, const InternalKey& b) const {
return Compare(a.Encode(), b.Encode());
}
inline bool ParseInternalKey(const Slice& internal_key,
ParsedInternalKey* result) {
const size_t n = internal_key.size();
if (n < 8) return false;
uint64_t num = DecodeFixed64(internal_key.data() + n - 8);
unsigned char c = num & 0xff;
result->sequence = num >> 8;
result->type = static_cast<ValueType>(c);
result->user_key = Slice(internal_key.data(), n - 8);
return (c <= static_cast<unsigned char>(kTypeValue));
}
// A helper class useful for DBImpl::Get()
class LookupKey {
public:
// Initialize *this for looking up user_key at a snapshot with
// the specified sequence number.
LookupKey(const Slice& user_key, SequenceNumber sequence);
~LookupKey();
// Return a key suitable for lookup in a MemTable.
Slice memtable_key() const { return Slice(start_, end_ - start_); }
// Return an internal key (suitable for passing to an internal iterator)
Slice internal_key() const { return Slice(kstart_, end_ - kstart_); }
// Return the user key
Slice user_key() const { return Slice(kstart_, end_ - kstart_ - 8); }
private:
// We construct a char array of the form:
// klength varint32 <-- start_
// userkey char[klength] <-- kstart_
// tag uint64
// <-- end_
// The array is a suitable MemTable key.
// The suffix starting with "userkey" can be used as an InternalKey.
const char* start_;
const char* kstart_;
const char* end_;
char space_[200]; // Avoid allocation for short keys
// No copying allowed
LookupKey(const LookupKey&);
void operator=(const LookupKey&);
};
inline LookupKey::~LookupKey() {
if (start_ != space_) delete[] start_;
}
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_FORMAT_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/dbformat.h"
#include "util/logging.h"
#include "util/testharness.h"
namespace leveldb {
static std::string IKey(const std::string& user_key,
uint64_t seq,
ValueType vt) {
std::string encoded;
AppendInternalKey(&encoded, ParsedInternalKey(user_key, seq, vt));
return encoded;
}
static std::string Shorten(const std::string& s, const std::string& l) {
std::string result = s;
InternalKeyComparator(BytewiseComparator()).FindShortestSeparator(&result, l);
return result;
}
static std::string ShortSuccessor(const std::string& s) {
std::string result = s;
InternalKeyComparator(BytewiseComparator()).FindShortSuccessor(&result);
return result;
}
static void TestKey(const std::string& key,
uint64_t seq,
ValueType vt) {
std::string encoded = IKey(key, seq, vt);
Slice in(encoded);
ParsedInternalKey decoded("", 0, kTypeValue);
ASSERT_TRUE(ParseInternalKey(in, &decoded));
ASSERT_EQ(key, decoded.user_key.ToString());
ASSERT_EQ(seq, decoded.sequence);
ASSERT_EQ(vt, decoded.type);
ASSERT_TRUE(!ParseInternalKey(Slice("bar"), &decoded));
}
class FormatTest { };
TEST(FormatTest, InternalKey_EncodeDecode) {
const char* keys[] = { "", "k", "hello", "longggggggggggggggggggggg" };
const uint64_t seq[] = {
1, 2, 3,
(1ull << 8) - 1, 1ull << 8, (1ull << 8) + 1,
(1ull << 16) - 1, 1ull << 16, (1ull << 16) + 1,
(1ull << 32) - 1, 1ull << 32, (1ull << 32) + 1
};
for (int k = 0; k < sizeof(keys) / sizeof(keys[0]); k++) {
for (int s = 0; s < sizeof(seq) / sizeof(seq[0]); s++) {
TestKey(keys[k], seq[s], kTypeValue);
TestKey("hello", 1, kTypeDeletion);
}
}
}
TEST(FormatTest, InternalKeyShortSeparator) {
// When user keys are same
ASSERT_EQ(IKey("foo", 100, kTypeValue),
Shorten(IKey("foo", 100, kTypeValue),
IKey("foo", 99, kTypeValue)));
ASSERT_EQ(IKey("foo", 100, kTypeValue),
Shorten(IKey("foo", 100, kTypeValue),
IKey("foo", 101, kTypeValue)));
ASSERT_EQ(IKey("foo", 100, kTypeValue),
Shorten(IKey("foo", 100, kTypeValue),
IKey("foo", 100, kTypeValue)));
ASSERT_EQ(IKey("foo", 100, kTypeValue),
Shorten(IKey("foo", 100, kTypeValue),
IKey("foo", 100, kTypeDeletion)));
// When user keys are misordered
ASSERT_EQ(IKey("foo", 100, kTypeValue),
Shorten(IKey("foo", 100, kTypeValue),
IKey("bar", 99, kTypeValue)));
// When user keys are different, but correctly ordered
ASSERT_EQ(IKey("g", kMaxSequenceNumber, kValueTypeForSeek),
Shorten(IKey("foo", 100, kTypeValue),
IKey("hello", 200, kTypeValue)));
// When start user key is prefix of limit user key
ASSERT_EQ(IKey("foo", 100, kTypeValue),
Shorten(IKey("foo", 100, kTypeValue),
IKey("foobar", 200, kTypeValue)));
// When limit user key is prefix of start user key
ASSERT_EQ(IKey("foobar", 100, kTypeValue),
Shorten(IKey("foobar", 100, kTypeValue),
IKey("foo", 200, kTypeValue)));
}
TEST(FormatTest, InternalKeyShortestSuccessor) {
ASSERT_EQ(IKey("g", kMaxSequenceNumber, kValueTypeForSeek),
ShortSuccessor(IKey("foo", 100, kTypeValue)));
ASSERT_EQ(IKey("\xff\xff", 100, kTypeValue),
ShortSuccessor(IKey("\xff\xff", 100, kTypeValue)));
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include <ctype.h>
#include <stdio.h>
#include "db/filename.h"
#include "db/dbformat.h"
#include "leveldb/env.h"
#include "util/logging.h"
namespace leveldb {
// A utility routine: write "data" to the named file and Sync() it.
extern Status WriteStringToFileSync(Env* env, const Slice& data,
const std::string& fname);
static std::string MakeFileName(const std::string& name, uint64_t number,
const char* suffix) {
char buf[100];
snprintf(buf, sizeof(buf), "/%06llu.%s",
static_cast<unsigned long long>(number),
suffix);
return name + buf;
}
std::string LogFileName(const std::string& name, uint64_t number) {
assert(number > 0);
return MakeFileName(name, number, "log");
}
std::string TableFileName(const std::string& name, uint64_t number) {
assert(number > 0);
return MakeFileName(name, number, "sst");
}
std::string DescriptorFileName(const std::string& dbname, uint64_t number) {
assert(number > 0);
char buf[100];
snprintf(buf, sizeof(buf), "/MANIFEST-%06llu",
static_cast<unsigned long long>(number));
return dbname + buf;
}
std::string CurrentFileName(const std::string& dbname) {
return dbname + "/CURRENT";
}
std::string LockFileName(const std::string& dbname) {
return dbname + "/LOCK";
}
std::string TempFileName(const std::string& dbname, uint64_t number) {
assert(number > 0);
return MakeFileName(dbname, number, "dbtmp");
}
std::string InfoLogFileName(const std::string& dbname) {
return dbname + "/LOG";
}
// Return the name of the old info log file for "dbname".
std::string OldInfoLogFileName(const std::string& dbname) {
return dbname + "/LOG.old";
}
// Owned filenames have the form:
// dbname/CURRENT
// dbname/LOCK
// dbname/LOG
// dbname/LOG.old
// dbname/MANIFEST-[0-9]+
// dbname/[0-9]+.(log|sst)
bool ParseFileName(const std::string& fname,
uint64_t* number,
FileType* type) {
Slice rest(fname);
if (rest == "CURRENT") {
*number = 0;
*type = kCurrentFile;
} else if (rest == "LOCK") {
*number = 0;
*type = kDBLockFile;
} else if (rest == "LOG" || rest == "LOG.old") {
*number = 0;
*type = kInfoLogFile;
} else if (rest.starts_with("MANIFEST-")) {
rest.remove_prefix(strlen("MANIFEST-"));
uint64_t num;
if (!ConsumeDecimalNumber(&rest, &num)) {
return false;
}
if (!rest.empty()) {
return false;
}
*type = kDescriptorFile;
*number = num;
} else {
// Avoid strtoull() to keep filename format independent of the
// current locale
uint64_t num;
if (!ConsumeDecimalNumber(&rest, &num)) {
return false;
}
Slice suffix = rest;
if (suffix == Slice(".log")) {
*type = kLogFile;
} else if (suffix == Slice(".sst")) {
*type = kTableFile;
} else if (suffix == Slice(".dbtmp")) {
*type = kTempFile;
} else {
return false;
}
*number = num;
}
return true;
}
Status SetCurrentFile(Env* env, const std::string& dbname,
uint64_t descriptor_number) {
// Remove leading "dbname/" and add newline to manifest file name
std::string manifest = DescriptorFileName(dbname, descriptor_number);
Slice contents = manifest;
assert(contents.starts_with(dbname + "/"));
contents.remove_prefix(dbname.size() + 1);
std::string tmp = TempFileName(dbname, descriptor_number);
Status s = WriteStringToFileSync(env, contents.ToString() + "\n", tmp);
if (s.ok()) {
s = env->RenameFile(tmp, CurrentFileName(dbname));
}
if (!s.ok()) {
env->DeleteFile(tmp);
}
return s;
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// File names used by DB code
#ifndef STORAGE_LEVELDB_DB_FILENAME_H_
#define STORAGE_LEVELDB_DB_FILENAME_H_
#include <stdint.h>
#include <string>
#include "leveldb/slice.h"
#include "leveldb/status.h"
#include "port/port.h"
namespace leveldb {
class Env;
enum FileType {
kLogFile,
kDBLockFile,
kTableFile,
kDescriptorFile,
kCurrentFile,
kTempFile,
kInfoLogFile // Either the current one, or an old one
};
// Return the name of the log file with the specified number
// in the db named by "dbname". The result will be prefixed with
// "dbname".
extern std::string LogFileName(const std::string& dbname, uint64_t number);
// Return the name of the sstable with the specified number
// in the db named by "dbname". The result will be prefixed with
// "dbname".
extern std::string TableFileName(const std::string& dbname, uint64_t number);
// Return the name of the descriptor file for the db named by
// "dbname" and the specified incarnation number. The result will be
// prefixed with "dbname".
extern std::string DescriptorFileName(const std::string& dbname,
uint64_t number);
// Return the name of the current file. This file contains the name
// of the current manifest file. The result will be prefixed with
// "dbname".
extern std::string CurrentFileName(const std::string& dbname);
// Return the name of the lock file for the db named by
// "dbname". The result will be prefixed with "dbname".
extern std::string LockFileName(const std::string& dbname);
// Return the name of a temporary file owned by the db named "dbname".
// The result will be prefixed with "dbname".
extern std::string TempFileName(const std::string& dbname, uint64_t number);
// Return the name of the info log file for "dbname".
extern std::string InfoLogFileName(const std::string& dbname);
// Return the name of the old info log file for "dbname".
extern std::string OldInfoLogFileName(const std::string& dbname);
// If filename is a leveldb file, store the type of the file in *type.
// The number encoded in the filename is stored in *number. If the
// filename was successfully parsed, returns true. Else return false.
extern bool ParseFileName(const std::string& filename,
uint64_t* number,
FileType* type);
// Make the CURRENT file point to the descriptor file with the
// specified number.
extern Status SetCurrentFile(Env* env, const std::string& dbname,
uint64_t descriptor_number);
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_FILENAME_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/filename.h"
#include "db/dbformat.h"
#include "port/port.h"
#include "util/logging.h"
#include "util/testharness.h"
namespace leveldb {
class FileNameTest { };
TEST(FileNameTest, Parse) {
Slice db;
FileType type;
uint64_t number;
// Successful parses
static struct {
const char* fname;
uint64_t number;
FileType type;
} cases[] = {
{ "100.log", 100, kLogFile },
{ "0.log", 0, kLogFile },
{ "0.sst", 0, kTableFile },
{ "CURRENT", 0, kCurrentFile },
{ "LOCK", 0, kDBLockFile },
{ "MANIFEST-2", 2, kDescriptorFile },
{ "MANIFEST-7", 7, kDescriptorFile },
{ "LOG", 0, kInfoLogFile },
{ "LOG.old", 0, kInfoLogFile },
{ "18446744073709551615.log", 18446744073709551615ull, kLogFile },
};
for (int i = 0; i < sizeof(cases) / sizeof(cases[0]); i++) {
std::string f = cases[i].fname;
ASSERT_TRUE(ParseFileName(f, &number, &type)) << f;
ASSERT_EQ(cases[i].type, type) << f;
ASSERT_EQ(cases[i].number, number) << f;
}
// Errors
static const char* errors[] = {
"",
"foo",
"foo-dx-100.log",
".log",
"",
"manifest",
"CURREN",
"CURRENTX",
"MANIFES",
"MANIFEST",
"MANIFEST-",
"XMANIFEST-3",
"MANIFEST-3x",
"LOC",
"LOCKx",
"LO",
"LOGx",
"18446744073709551616.log",
"184467440737095516150.log",
"100",
"100.",
"100.lop"
};
for (int i = 0; i < sizeof(errors) / sizeof(errors[0]); i++) {
std::string f = errors[i];
ASSERT_TRUE(!ParseFileName(f, &number, &type)) << f;
};
}
TEST(FileNameTest, Construction) {
uint64_t number;
FileType type;
std::string fname;
fname = CurrentFileName("foo");
ASSERT_EQ("foo/", std::string(fname.data(), 4));
ASSERT_TRUE(ParseFileName(fname.c_str() + 4, &number, &type));
ASSERT_EQ(0, number);
ASSERT_EQ(kCurrentFile, type);
fname = LockFileName("foo");
ASSERT_EQ("foo/", std::string(fname.data(), 4));
ASSERT_TRUE(ParseFileName(fname.c_str() + 4, &number, &type));
ASSERT_EQ(0, number);
ASSERT_EQ(kDBLockFile, type);
fname = LogFileName("foo", 192);
ASSERT_EQ("foo/", std::string(fname.data(), 4));
ASSERT_TRUE(ParseFileName(fname.c_str() + 4, &number, &type));
ASSERT_EQ(192, number);
ASSERT_EQ(kLogFile, type);
fname = TableFileName("bar", 200);
ASSERT_EQ("bar/", std::string(fname.data(), 4));
ASSERT_TRUE(ParseFileName(fname.c_str() + 4, &number, &type));
ASSERT_EQ(200, number);
ASSERT_EQ(kTableFile, type);
fname = DescriptorFileName("bar", 100);
ASSERT_EQ("bar/", std::string(fname.data(), 4));
ASSERT_TRUE(ParseFileName(fname.c_str() + 4, &number, &type));
ASSERT_EQ(100, number);
ASSERT_EQ(kDescriptorFile, type);
fname = TempFileName("tmp", 999);
ASSERT_EQ("tmp/", std::string(fname.data(), 4));
ASSERT_TRUE(ParseFileName(fname.c_str() + 4, &number, &type));
ASSERT_EQ(999, number);
ASSERT_EQ(kTempFile, type);
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// Log format information shared by reader and writer.
// See ../doc/log_format.txt for more detail.
#ifndef STORAGE_LEVELDB_DB_LOG_FORMAT_H_
#define STORAGE_LEVELDB_DB_LOG_FORMAT_H_
namespace leveldb {
namespace log {
enum RecordType {
// Zero is reserved for preallocated files
kZeroType = 0,
kFullType = 1,
// For fragments
kFirstType = 2,
kMiddleType = 3,
kLastType = 4
};
static const int kMaxRecordType = kLastType;
static const int kBlockSize = 32768;
// Header is checksum (4 bytes), type (1 byte), length (2 bytes).
static const int kHeaderSize = 4 + 1 + 2;
} // namespace log
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_LOG_FORMAT_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/log_reader.h"
#include <stdio.h>
#include "leveldb/env.h"
#include "util/coding.h"
#include "util/crc32c.h"
namespace leveldb {
namespace log {
Reader::Reporter::~Reporter() {
}
Reader::Reader(SequentialFile* file, Reporter* reporter, bool checksum,
uint64_t initial_offset)
: file_(file),
reporter_(reporter),
checksum_(checksum),
backing_store_(new char[kBlockSize]),
buffer_(),
eof_(false),
last_record_offset_(0),
end_of_buffer_offset_(0),
initial_offset_(initial_offset) {
}
Reader::~Reader() {
delete[] backing_store_;
}
bool Reader::SkipToInitialBlock() {
size_t offset_in_block = initial_offset_ % kBlockSize;
uint64_t block_start_location = initial_offset_ - offset_in_block;
// Don't search a block if we'd be in the trailer
if (offset_in_block > kBlockSize - 6) {
offset_in_block = 0;
block_start_location += kBlockSize;
}
end_of_buffer_offset_ = block_start_location;
// Skip to start of first block that can contain the initial record
if (block_start_location > 0) {
Status skip_status = file_->Skip(block_start_location);
if (!skip_status.ok()) {
ReportDrop(block_start_location, skip_status);
return false;
}
}
return true;
}
bool Reader::ReadRecord(Slice* record, std::string* scratch) {
if (last_record_offset_ < initial_offset_) {
if (!SkipToInitialBlock()) {
return false;
}
}
scratch->clear();
record->clear();
bool in_fragmented_record = false;
// Record offset of the logical record that we're reading
// 0 is a dummy value to make compilers happy
uint64_t prospective_record_offset = 0;
Slice fragment;
while (true) {
uint64_t physical_record_offset = end_of_buffer_offset_ - buffer_.size();
const unsigned int record_type = ReadPhysicalRecord(&fragment);
switch (record_type) {
case kFullType:
if (in_fragmented_record) {
// Handle bug in earlier versions of log::Writer where
// it could emit an empty kFirstType record at the tail end
// of a block followed by a kFullType or kFirstType record
// at the beginning of the next block.
if (scratch->empty()) {
in_fragmented_record = false;
} else {
ReportCorruption(scratch->size(), "partial record without end(1)");
}
}
prospective_record_offset = physical_record_offset;
scratch->clear();
*record = fragment;
last_record_offset_ = prospective_record_offset;
return true;
case kFirstType:
if (in_fragmented_record) {
// Handle bug in earlier versions of log::Writer where
// it could emit an empty kFirstType record at the tail end
// of a block followed by a kFullType or kFirstType record
// at the beginning of the next block.
if (scratch->empty()) {
in_fragmented_record = false;
} else {
ReportCorruption(scratch->size(), "partial record without end(2)");
}
}
prospective_record_offset = physical_record_offset;
scratch->assign(fragment.data(), fragment.size());
in_fragmented_record = true;
break;
case kMiddleType:
if (!in_fragmented_record) {
ReportCorruption(fragment.size(),
"missing start of fragmented record(1)");
} else {
scratch->append(fragment.data(), fragment.size());
}
break;
case kLastType:
if (!in_fragmented_record) {
ReportCorruption(fragment.size(),
"missing start of fragmented record(2)");
} else {
scratch->append(fragment.data(), fragment.size());
*record = Slice(*scratch);
last_record_offset_ = prospective_record_offset;
return true;
}
break;
case kEof:
if (in_fragmented_record) {
ReportCorruption(scratch->size(), "partial record without end(3)");
scratch->clear();
}
return false;
case kBadRecord:
if (in_fragmented_record) {
ReportCorruption(scratch->size(), "error in middle of record");
in_fragmented_record = false;
scratch->clear();
}
break;
default: {
char buf[40];
snprintf(buf, sizeof(buf), "unknown record type %u", record_type);
ReportCorruption(
(fragment.size() + (in_fragmented_record ? scratch->size() : 0)),
buf);
in_fragmented_record = false;
scratch->clear();
break;
}
}
}
return false;
}
uint64_t Reader::LastRecordOffset() {
return last_record_offset_;
}
void Reader::ReportCorruption(size_t bytes, const char* reason) {
ReportDrop(bytes, Status::Corruption(reason));
}
void Reader::ReportDrop(size_t bytes, const Status& reason) {
if (reporter_ != NULL &&
end_of_buffer_offset_ - buffer_.size() - bytes >= initial_offset_) {
reporter_->Corruption(bytes, reason);
}
}
unsigned int Reader::ReadPhysicalRecord(Slice* result) {
while (true) {
if (buffer_.size() < kHeaderSize) {
if (!eof_) {
// Last read was a full read, so this is a trailer to skip
buffer_.clear();
Status status = file_->Read(kBlockSize, &buffer_, backing_store_);
end_of_buffer_offset_ += buffer_.size();
if (!status.ok()) {
buffer_.clear();
ReportDrop(kBlockSize, status);
eof_ = true;
return kEof;
} else if (buffer_.size() < kBlockSize) {
eof_ = true;
}
continue;
} else if (buffer_.size() == 0) {
// End of file
return kEof;
} else {
size_t drop_size = buffer_.size();
buffer_.clear();
ReportCorruption(drop_size, "truncated record at end of file");
return kEof;
}
}
// Parse the header
const char* header = buffer_.data();
const uint32_t a = static_cast<uint32_t>(header[4]) & 0xff;
const uint32_t b = static_cast<uint32_t>(header[5]) & 0xff;
const unsigned int type = header[6];
const uint32_t length = a | (b << 8);
if (kHeaderSize + length > buffer_.size()) {
size_t drop_size = buffer_.size();
buffer_.clear();
ReportCorruption(drop_size, "bad record length");
return kBadRecord;
}
if (type == kZeroType && length == 0) {
// Skip zero length record without reporting any drops since
// such records are produced by the mmap based writing code in
// env_posix.cc that preallocates file regions.
buffer_.clear();
return kBadRecord;
}
// Check crc
if (checksum_) {
uint32_t expected_crc = crc32c::Unmask(DecodeFixed32(header));
uint32_t actual_crc = crc32c::Value(header + 6, 1 + length);
if (actual_crc != expected_crc) {
// Drop the rest of the buffer since "length" itself may have
// been corrupted and if we trust it, we could find some
// fragment of a real log record that just happens to look
// like a valid log record.
size_t drop_size = buffer_.size();
buffer_.clear();
ReportCorruption(drop_size, "checksum mismatch");
return kBadRecord;
}
}
buffer_.remove_prefix(kHeaderSize + length);
// Skip physical record that started before initial_offset_
if (end_of_buffer_offset_ - buffer_.size() - kHeaderSize - length <
initial_offset_) {
result->clear();
return kBadRecord;
}
*result = Slice(header + kHeaderSize, length);
return type;
}
}
} // namespace log
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_LOG_READER_H_
#define STORAGE_LEVELDB_DB_LOG_READER_H_
#include <stdint.h>
#include "db/log_format.h"
#include "leveldb/slice.h"
#include "leveldb/status.h"
namespace leveldb {
class SequentialFile;
namespace log {
class Reader {
public:
// Interface for reporting errors.
class Reporter {
public:
virtual ~Reporter();
// Some corruption was detected. "size" is the approximate number
// of bytes dropped due to the corruption.
virtual void Corruption(size_t bytes, const Status& status) = 0;
};
// Create a reader that will return log records from "*file".
// "*file" must remain live while this Reader is in use.
//
// If "reporter" is non-NULL, it is notified whenever some data is
// dropped due to a detected corruption. "*reporter" must remain
// live while this Reader is in use.
//
// If "checksum" is true, verify checksums if available.
//
// The Reader will start reading at the first record located at physical
// position >= initial_offset within the file.
Reader(SequentialFile* file, Reporter* reporter, bool checksum,
uint64_t initial_offset);
~Reader();
// Read the next record into *record. Returns true if read
// successfully, false if we hit end of the input. May use
// "*scratch" as temporary storage. The contents filled in *record
// will only be valid until the next mutating operation on this
// reader or the next mutation to *scratch.
bool ReadRecord(Slice* record, std::string* scratch);
// Returns the physical offset of the last record returned by ReadRecord.
//
// Undefined before the first call to ReadRecord.
uint64_t LastRecordOffset();
private:
SequentialFile* const file_;
Reporter* const reporter_;
bool const checksum_;
char* const backing_store_;
Slice buffer_;
bool eof_; // Last Read() indicated EOF by returning < kBlockSize
// Offset of the last record returned by ReadRecord.
uint64_t last_record_offset_;
// Offset of the first location past the end of buffer_.
uint64_t end_of_buffer_offset_;
// Offset at which to start looking for the first record to return
uint64_t const initial_offset_;
// Extend record types with the following special values
enum {
kEof = kMaxRecordType + 1,
// Returned whenever we find an invalid physical record.
// Currently there are three situations in which this happens:
// * The record has an invalid CRC (ReadPhysicalRecord reports a drop)
// * The record is a 0-length record (No drop is reported)
// * The record is below constructor's initial_offset (No drop is reported)
kBadRecord = kMaxRecordType + 2
};
// Skips all blocks that are completely before "initial_offset_".
//
// Returns true on success. Handles reporting.
bool SkipToInitialBlock();
// Return type, or one of the preceding special values
unsigned int ReadPhysicalRecord(Slice* result);
// Reports dropped bytes to the reporter.
// buffer_ must be updated to remove the dropped bytes prior to invocation.
void ReportCorruption(size_t bytes, const char* reason);
void ReportDrop(size_t bytes, const Status& reason);
// No copying allowed
Reader(const Reader&);
void operator=(const Reader&);
};
} // namespace log
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_LOG_READER_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/log_reader.h"
#include "db/log_writer.h"
#include "leveldb/env.h"
#include "util/coding.h"
#include "util/crc32c.h"
#include "util/random.h"
#include "util/testharness.h"
namespace leveldb {
namespace log {
// Construct a string of the specified length made out of the supplied
// partial string.
static std::string BigString(const std::string& partial_string, size_t n) {
std::string result;
while (result.size() < n) {
result.append(partial_string);
}
result.resize(n);
return result;
}
// Construct a string from a number
static std::string NumberString(int n) {
char buf[50];
snprintf(buf, sizeof(buf), "%d.", n);
return std::string(buf);
}
// Return a skewed potentially long string
static std::string RandomSkewedString(int i, Random* rnd) {
return BigString(NumberString(i), rnd->Skewed(17));
}
class LogTest {
private:
class StringDest : public WritableFile {
public:
std::string contents_;
virtual Status Close() { return Status::OK(); }
virtual Status Flush() { return Status::OK(); }
virtual Status Sync() { return Status::OK(); }
virtual Status Append(const Slice& slice) {
contents_.append(slice.data(), slice.size());
return Status::OK();
}
};
class StringSource : public SequentialFile {
public:
Slice contents_;
bool force_error_;
bool returned_partial_;
StringSource() : force_error_(false), returned_partial_(false) { }
virtual Status Read(size_t n, Slice* result, char* scratch) {
ASSERT_TRUE(!returned_partial_) << "must not Read() after eof/error";
if (force_error_) {
force_error_ = false;
returned_partial_ = true;
return Status::Corruption("read error");
}
if (contents_.size() < n) {
n = contents_.size();
returned_partial_ = true;
}
*result = Slice(contents_.data(), n);
contents_.remove_prefix(n);
return Status::OK();
}
virtual Status Skip(uint64_t n) {
if (n > contents_.size()) {
contents_.clear();
return Status::NotFound("in-memory file skipepd past end");
}
contents_.remove_prefix(n);
return Status::OK();
}
};
class ReportCollector : public Reader::Reporter {
public:
size_t dropped_bytes_;
std::string message_;
ReportCollector() : dropped_bytes_(0) { }
virtual void Corruption(size_t bytes, const Status& status) {
dropped_bytes_ += bytes;
message_.append(status.ToString());
}
};
StringDest dest_;
StringSource source_;
ReportCollector report_;
bool reading_;
Writer writer_;
Reader reader_;
// Record metadata for testing initial offset functionality
static size_t initial_offset_record_sizes_[];
static uint64_t initial_offset_last_record_offsets_[];
public:
LogTest() : reading_(false),
writer_(&dest_),
reader_(&source_, &report_, true/*checksum*/,
0/*initial_offset*/) {
}
void Write(const std::string& msg) {
ASSERT_TRUE(!reading_) << "Write() after starting to read";
writer_.AddRecord(Slice(msg));
}
size_t WrittenBytes() const {
return dest_.contents_.size();
}
std::string Read() {
if (!reading_) {
reading_ = true;
source_.contents_ = Slice(dest_.contents_);
}
std::string scratch;
Slice record;
if (reader_.ReadRecord(&record, &scratch)) {
return record.ToString();
} else {
return "EOF";
}
}
void IncrementByte(int offset, int delta) {
dest_.contents_[offset] += delta;
}
void SetByte(int offset, char new_byte) {
dest_.contents_[offset] = new_byte;
}
void ShrinkSize(int bytes) {
dest_.contents_.resize(dest_.contents_.size() - bytes);
}
void FixChecksum(int header_offset, int len) {
// Compute crc of type/len/data
uint32_t crc = crc32c::Value(&dest_.contents_[header_offset+6], 1 + len);
crc = crc32c::Mask(crc);
EncodeFixed32(&dest_.contents_[header_offset], crc);
}
void ForceError() {
source_.force_error_ = true;
}
size_t DroppedBytes() const {
return report_.dropped_bytes_;
}
std::string ReportMessage() const {
return report_.message_;
}
// Returns OK iff recorded error message contains "msg"
std::string MatchError(const std::string& msg) const {
if (report_.message_.find(msg) == std::string::npos) {
return report_.message_;
} else {
return "OK";
}
}
void WriteInitialOffsetLog() {
for (int i = 0; i < 4; i++) {
std::string record(initial_offset_record_sizes_[i],
static_cast<char>('a' + i));
Write(record);
}
}
void CheckOffsetPastEndReturnsNoRecords(uint64_t offset_past_end) {
WriteInitialOffsetLog();
reading_ = true;
source_.contents_ = Slice(dest_.contents_);
Reader* offset_reader = new Reader(&source_, &report_, true/*checksum*/,
WrittenBytes() + offset_past_end);
Slice record;
std::string scratch;
ASSERT_TRUE(!offset_reader->ReadRecord(&record, &scratch));
delete offset_reader;
}
void CheckInitialOffsetRecord(uint64_t initial_offset,
int expected_record_offset) {
WriteInitialOffsetLog();
reading_ = true;
source_.contents_ = Slice(dest_.contents_);
Reader* offset_reader = new Reader(&source_, &report_, true/*checksum*/,
initial_offset);
Slice record;
std::string scratch;
ASSERT_TRUE(offset_reader->ReadRecord(&record, &scratch));
ASSERT_EQ(initial_offset_record_sizes_[expected_record_offset],
record.size());
ASSERT_EQ(initial_offset_last_record_offsets_[expected_record_offset],
offset_reader->LastRecordOffset());
ASSERT_EQ((char)('a' + expected_record_offset), record.data()[0]);
delete offset_reader;
}
};
size_t LogTest::initial_offset_record_sizes_[] =
{10000, // Two sizable records in first block
10000,
2 * log::kBlockSize - 1000, // Span three blocks
1};
uint64_t LogTest::initial_offset_last_record_offsets_[] =
{0,
kHeaderSize + 10000,
2 * (kHeaderSize + 10000),
2 * (kHeaderSize + 10000) +
(2 * log::kBlockSize - 1000) + 3 * kHeaderSize};
TEST(LogTest, Empty) {
ASSERT_EQ("EOF", Read());
}
TEST(LogTest, ReadWrite) {
Write("foo");
Write("bar");
Write("");
Write("xxxx");
ASSERT_EQ("foo", Read());
ASSERT_EQ("bar", Read());
ASSERT_EQ("", Read());
ASSERT_EQ("xxxx", Read());
ASSERT_EQ("EOF", Read());
ASSERT_EQ("EOF", Read()); // Make sure reads at eof work
}
TEST(LogTest, ManyBlocks) {
for (int i = 0; i < 100000; i++) {
Write(NumberString(i));
}
for (int i = 0; i < 100000; i++) {
ASSERT_EQ(NumberString(i), Read());
}
ASSERT_EQ("EOF", Read());
}
TEST(LogTest, Fragmentation) {
Write("small");
Write(BigString("medium", 50000));
Write(BigString("large", 100000));
ASSERT_EQ("small", Read());
ASSERT_EQ(BigString("medium", 50000), Read());
ASSERT_EQ(BigString("large", 100000), Read());
ASSERT_EQ("EOF", Read());
}
TEST(LogTest, MarginalTrailer) {
// Make a trailer that is exactly the same length as an empty record.
const int n = kBlockSize - 2*kHeaderSize;
Write(BigString("foo", n));
ASSERT_EQ(kBlockSize - kHeaderSize, WrittenBytes());
Write("");
Write("bar");
ASSERT_EQ(BigString("foo", n), Read());
ASSERT_EQ("", Read());
ASSERT_EQ("bar", Read());
ASSERT_EQ("EOF", Read());
}
TEST(LogTest, MarginalTrailer2) {
// Make a trailer that is exactly the same length as an empty record.
const int n = kBlockSize - 2*kHeaderSize;
Write(BigString("foo", n));
ASSERT_EQ(kBlockSize - kHeaderSize, WrittenBytes());
Write("bar");
ASSERT_EQ(BigString("foo", n), Read());
ASSERT_EQ("bar", Read());
ASSERT_EQ("EOF", Read());
ASSERT_EQ(0, DroppedBytes());
ASSERT_EQ("", ReportMessage());
}
TEST(LogTest, ShortTrailer) {
const int n = kBlockSize - 2*kHeaderSize + 4;
Write(BigString("foo", n));
ASSERT_EQ(kBlockSize - kHeaderSize + 4, WrittenBytes());
Write("");
Write("bar");
ASSERT_EQ(BigString("foo", n), Read());
ASSERT_EQ("", Read());
ASSERT_EQ("bar", Read());
ASSERT_EQ("EOF", Read());
}
TEST(LogTest, AlignedEof) {
const int n = kBlockSize - 2*kHeaderSize + 4;
Write(BigString("foo", n));
ASSERT_EQ(kBlockSize - kHeaderSize + 4, WrittenBytes());
ASSERT_EQ(BigString("foo", n), Read());
ASSERT_EQ("EOF", Read());
}
TEST(LogTest, RandomRead) {
const int N = 500;
Random write_rnd(301);
for (int i = 0; i < N; i++) {
Write(RandomSkewedString(i, &write_rnd));
}
Random read_rnd(301);
for (int i = 0; i < N; i++) {
ASSERT_EQ(RandomSkewedString(i, &read_rnd), Read());
}
ASSERT_EQ("EOF", Read());
}
// Tests of all the error paths in log_reader.cc follow:
TEST(LogTest, ReadError) {
Write("foo");
ForceError();
ASSERT_EQ("EOF", Read());
ASSERT_EQ(kBlockSize, DroppedBytes());
ASSERT_EQ("OK", MatchError("read error"));
}
TEST(LogTest, BadRecordType) {
Write("foo");
// Type is stored in header[6]
IncrementByte(6, 100);
FixChecksum(0, 3);
ASSERT_EQ("EOF", Read());
ASSERT_EQ(3, DroppedBytes());
ASSERT_EQ("OK", MatchError("unknown record type"));
}
TEST(LogTest, TruncatedTrailingRecord) {
Write("foo");
ShrinkSize(4); // Drop all payload as well as a header byte
ASSERT_EQ("EOF", Read());
ASSERT_EQ(kHeaderSize - 1, DroppedBytes());
ASSERT_EQ("OK", MatchError("truncated record at end of file"));
}
TEST(LogTest, BadLength) {
Write("foo");
ShrinkSize(1);
ASSERT_EQ("EOF", Read());
ASSERT_EQ(kHeaderSize + 2, DroppedBytes());
ASSERT_EQ("OK", MatchError("bad record length"));
}
TEST(LogTest, ChecksumMismatch) {
Write("foo");
IncrementByte(0, 10);
ASSERT_EQ("EOF", Read());
ASSERT_EQ(10, DroppedBytes());
ASSERT_EQ("OK", MatchError("checksum mismatch"));
}
TEST(LogTest, UnexpectedMiddleType) {
Write("foo");
SetByte(6, kMiddleType);
FixChecksum(0, 3);
ASSERT_EQ("EOF", Read());
ASSERT_EQ(3, DroppedBytes());
ASSERT_EQ("OK", MatchError("missing start"));
}
TEST(LogTest, UnexpectedLastType) {
Write("foo");
SetByte(6, kLastType);
FixChecksum(0, 3);
ASSERT_EQ("EOF", Read());
ASSERT_EQ(3, DroppedBytes());
ASSERT_EQ("OK", MatchError("missing start"));
}
TEST(LogTest, UnexpectedFullType) {
Write("foo");
Write("bar");
SetByte(6, kFirstType);
FixChecksum(0, 3);
ASSERT_EQ("bar", Read());
ASSERT_EQ("EOF", Read());
ASSERT_EQ(3, DroppedBytes());
ASSERT_EQ("OK", MatchError("partial record without end"));
}
TEST(LogTest, UnexpectedFirstType) {
Write("foo");
Write(BigString("bar", 100000));
SetByte(6, kFirstType);
FixChecksum(0, 3);
ASSERT_EQ(BigString("bar", 100000), Read());
ASSERT_EQ("EOF", Read());
ASSERT_EQ(3, DroppedBytes());
ASSERT_EQ("OK", MatchError("partial record without end"));
}
TEST(LogTest, ErrorJoinsRecords) {
// Consider two fragmented records:
// first(R1) last(R1) first(R2) last(R2)
// where the middle two fragments disappear. We do not want
// first(R1),last(R2) to get joined and returned as a valid record.
// Write records that span two blocks
Write(BigString("foo", kBlockSize));
Write(BigString("bar", kBlockSize));
Write("correct");
// Wipe the middle block
for (int offset = kBlockSize; offset < 2*kBlockSize; offset++) {
SetByte(offset, 'x');
}
ASSERT_EQ("correct", Read());
ASSERT_EQ("EOF", Read());
const int dropped = DroppedBytes();
ASSERT_LE(dropped, 2*kBlockSize + 100);
ASSERT_GE(dropped, 2*kBlockSize);
}
TEST(LogTest, ReadStart) {
CheckInitialOffsetRecord(0, 0);
}
TEST(LogTest, ReadSecondOneOff) {
CheckInitialOffsetRecord(1, 1);
}
TEST(LogTest, ReadSecondTenThousand) {
CheckInitialOffsetRecord(10000, 1);
}
TEST(LogTest, ReadSecondStart) {
CheckInitialOffsetRecord(10007, 1);
}
TEST(LogTest, ReadThirdOneOff) {
CheckInitialOffsetRecord(10008, 2);
}
TEST(LogTest, ReadThirdStart) {
CheckInitialOffsetRecord(20014, 2);
}
TEST(LogTest, ReadFourthOneOff) {
CheckInitialOffsetRecord(20015, 3);
}
TEST(LogTest, ReadFourthFirstBlockTrailer) {
CheckInitialOffsetRecord(log::kBlockSize - 4, 3);
}
TEST(LogTest, ReadFourthMiddleBlock) {
CheckInitialOffsetRecord(log::kBlockSize + 1, 3);
}
TEST(LogTest, ReadFourthLastBlock) {
CheckInitialOffsetRecord(2 * log::kBlockSize + 1, 3);
}
TEST(LogTest, ReadFourthStart) {
CheckInitialOffsetRecord(
2 * (kHeaderSize + 1000) + (2 * log::kBlockSize - 1000) + 3 * kHeaderSize,
3);
}
TEST(LogTest, ReadEnd) {
CheckOffsetPastEndReturnsNoRecords(0);
}
TEST(LogTest, ReadPastEnd) {
CheckOffsetPastEndReturnsNoRecords(5);
}
} // namespace log
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/log_writer.h"
#include <stdint.h>
#include "leveldb/env.h"
#include "util/coding.h"
#include "util/crc32c.h"
namespace leveldb {
namespace log {
Writer::Writer(WritableFile* dest)
: dest_(dest),
block_offset_(0) {
for (int i = 0; i <= kMaxRecordType; i++) {
char t = static_cast<char>(i);
type_crc_[i] = crc32c::Value(&t, 1);
}
}
Writer::~Writer() {
}
Status Writer::AddRecord(const Slice& slice) {
const char* ptr = slice.data();
size_t left = slice.size();
// Fragment the record if necessary and emit it. Note that if slice
// is empty, we still want to iterate once to emit a single
// zero-length record
Status s;
bool begin = true;
do {
const int leftover = kBlockSize - block_offset_;
assert(leftover >= 0);
if (leftover < kHeaderSize) {
// Switch to a new block
if (leftover > 0) {
// Fill the trailer (literal below relies on kHeaderSize being 7)
assert(kHeaderSize == 7);
dest_->Append(Slice("\x00\x00\x00\x00\x00\x00", leftover));
}
block_offset_ = 0;
}
// Invariant: we never leave < kHeaderSize bytes in a block.
assert(kBlockSize - block_offset_ - kHeaderSize >= 0);
const size_t avail = kBlockSize - block_offset_ - kHeaderSize;
const size_t fragment_length = (left < avail) ? left : avail;
RecordType type;
const bool end = (left == fragment_length);
if (begin && end) {
type = kFullType;
} else if (begin) {
type = kFirstType;
} else if (end) {
type = kLastType;
} else {
type = kMiddleType;
}
s = EmitPhysicalRecord(type, ptr, fragment_length);
ptr += fragment_length;
left -= fragment_length;
begin = false;
} while (s.ok() && left > 0);
return s;
}
Status Writer::EmitPhysicalRecord(RecordType t, const char* ptr, size_t n) {
assert(n <= 0xffff); // Must fit in two bytes
assert(block_offset_ + kHeaderSize + n <= kBlockSize);
// Format the header
char buf[kHeaderSize];
buf[4] = static_cast<char>(n & 0xff);
buf[5] = static_cast<char>(n >> 8);
buf[6] = static_cast<char>(t);
// Compute the crc of the record type and the payload.
uint32_t crc = crc32c::Extend(type_crc_[t], ptr, n);
crc = crc32c::Mask(crc); // Adjust for storage
EncodeFixed32(buf, crc);
// Write the header and the payload
Status s = dest_->Append(Slice(buf, kHeaderSize));
if (s.ok()) {
s = dest_->Append(Slice(ptr, n));
if (s.ok()) {
s = dest_->Flush();
}
}
block_offset_ += kHeaderSize + n;
return s;
}
} // namespace log
} // namespace leveldb

48
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@ -1,48 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_LOG_WRITER_H_
#define STORAGE_LEVELDB_DB_LOG_WRITER_H_
#include <stdint.h>
#include "db/log_format.h"
#include "leveldb/slice.h"
#include "leveldb/status.h"
namespace leveldb {
class WritableFile;
namespace log {
class Writer {
public:
// Create a writer that will append data to "*dest".
// "*dest" must be initially empty.
// "*dest" must remain live while this Writer is in use.
explicit Writer(WritableFile* dest);
~Writer();
Status AddRecord(const Slice& slice);
private:
WritableFile* dest_;
int block_offset_; // Current offset in block
// crc32c values for all supported record types. These are
// pre-computed to reduce the overhead of computing the crc of the
// record type stored in the header.
uint32_t type_crc_[kMaxRecordType + 1];
Status EmitPhysicalRecord(RecordType type, const char* ptr, size_t length);
// No copying allowed
Writer(const Writer&);
void operator=(const Writer&);
};
} // namespace log
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_LOG_WRITER_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/memtable.h"
#include "db/dbformat.h"
#include "leveldb/comparator.h"
#include "leveldb/env.h"
#include "leveldb/iterator.h"
#include "util/coding.h"
namespace leveldb {
static Slice GetLengthPrefixedSlice(const char* data) {
uint32_t len;
const char* p = data;
p = GetVarint32Ptr(p, p + 5, &len); // +5: we assume "p" is not corrupted
return Slice(p, len);
}
MemTable::MemTable(const InternalKeyComparator& cmp)
: comparator_(cmp),
refs_(0),
table_(comparator_, &arena_) {
}
MemTable::~MemTable() {
assert(refs_ == 0);
}
size_t MemTable::ApproximateMemoryUsage() { return arena_.MemoryUsage(); }
int MemTable::KeyComparator::operator()(const char* aptr, const char* bptr)
const {
// Internal keys are encoded as length-prefixed strings.
Slice a = GetLengthPrefixedSlice(aptr);
Slice b = GetLengthPrefixedSlice(bptr);
return comparator.Compare(a, b);
}
// Encode a suitable internal key target for "target" and return it.
// Uses *scratch as scratch space, and the returned pointer will point
// into this scratch space.
static const char* EncodeKey(std::string* scratch, const Slice& target) {
scratch->clear();
PutVarint32(scratch, target.size());
scratch->append(target.data(), target.size());
return scratch->data();
}
class MemTableIterator: public Iterator {
public:
explicit MemTableIterator(MemTable::Table* table) : iter_(table) { }
virtual bool Valid() const { return iter_.Valid(); }
virtual void Seek(const Slice& k) { iter_.Seek(EncodeKey(&tmp_, k)); }
virtual void SeekToFirst() { iter_.SeekToFirst(); }
virtual void SeekToLast() { iter_.SeekToLast(); }
virtual void Next() { iter_.Next(); }
virtual void Prev() { iter_.Prev(); }
virtual Slice key() const { return GetLengthPrefixedSlice(iter_.key()); }
virtual Slice value() const {
Slice key_slice = GetLengthPrefixedSlice(iter_.key());
return GetLengthPrefixedSlice(key_slice.data() + key_slice.size());
}
virtual Status status() const { return Status::OK(); }
private:
MemTable::Table::Iterator iter_;
std::string tmp_; // For passing to EncodeKey
// No copying allowed
MemTableIterator(const MemTableIterator&);
void operator=(const MemTableIterator&);
};
Iterator* MemTable::NewIterator() {
return new MemTableIterator(&table_);
}
void MemTable::Add(SequenceNumber s, ValueType type,
const Slice& key,
const Slice& value) {
// Format of an entry is concatenation of:
// key_size : varint32 of internal_key.size()
// key bytes : char[internal_key.size()]
// value_size : varint32 of value.size()
// value bytes : char[value.size()]
size_t key_size = key.size();
size_t val_size = value.size();
size_t internal_key_size = key_size + 8;
const size_t encoded_len =
VarintLength(internal_key_size) + internal_key_size +
VarintLength(val_size) + val_size;
char* buf = arena_.Allocate(encoded_len);
char* p = EncodeVarint32(buf, internal_key_size);
memcpy(p, key.data(), key_size);
p += key_size;
EncodeFixed64(p, (s << 8) | type);
p += 8;
p = EncodeVarint32(p, val_size);
memcpy(p, value.data(), val_size);
assert((p + val_size) - buf == encoded_len);
table_.Insert(buf);
}
bool MemTable::Get(const LookupKey& key, std::string* value, Status* s) {
Slice memkey = key.memtable_key();
Table::Iterator iter(&table_);
iter.Seek(memkey.data());
if (iter.Valid()) {
// entry format is:
// klength varint32
// userkey char[klength]
// tag uint64
// vlength varint32
// value char[vlength]
// Check that it belongs to same user key. We do not check the
// sequence number since the Seek() call above should have skipped
// all entries with overly large sequence numbers.
const char* entry = iter.key();
uint32_t key_length;
const char* key_ptr = GetVarint32Ptr(entry, entry+5, &key_length);
if (comparator_.comparator.user_comparator()->Compare(
Slice(key_ptr, key_length - 8),
key.user_key()) == 0) {
// Correct user key
const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
switch (static_cast<ValueType>(tag & 0xff)) {
case kTypeValue: {
Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
value->assign(v.data(), v.size());
return true;
}
case kTypeDeletion:
*s = Status::NotFound(Slice());
return true;
}
}
}
return false;
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_MEMTABLE_H_
#define STORAGE_LEVELDB_DB_MEMTABLE_H_
#include <string>
#include "leveldb/db.h"
#include "db/dbformat.h"
#include "db/skiplist.h"
#include "util/arena.h"
namespace leveldb {
class InternalKeyComparator;
class Mutex;
class MemTableIterator;
class MemTable {
public:
// MemTables are reference counted. The initial reference count
// is zero and the caller must call Ref() at least once.
explicit MemTable(const InternalKeyComparator& comparator);
// Increase reference count.
void Ref() { ++refs_; }
// Drop reference count. Delete if no more references exist.
void Unref() {
--refs_;
assert(refs_ >= 0);
if (refs_ <= 0) {
delete this;
}
}
// Returns an estimate of the number of bytes of data in use by this
// data structure.
//
// REQUIRES: external synchronization to prevent simultaneous
// operations on the same MemTable.
size_t ApproximateMemoryUsage();
// Return an iterator that yields the contents of the memtable.
//
// The caller must ensure that the underlying MemTable remains live
// while the returned iterator is live. The keys returned by this
// iterator are internal keys encoded by AppendInternalKey in the
// db/format.{h,cc} module.
Iterator* NewIterator();
// Add an entry into memtable that maps key to value at the
// specified sequence number and with the specified type.
// Typically value will be empty if type==kTypeDeletion.
void Add(SequenceNumber seq, ValueType type,
const Slice& key,
const Slice& value);
// If memtable contains a value for key, store it in *value and return true.
// If memtable contains a deletion for key, store a NotFound() error
// in *status and return true.
// Else, return false.
bool Get(const LookupKey& key, std::string* value, Status* s);
private:
~MemTable(); // Private since only Unref() should be used to delete it
struct KeyComparator {
const InternalKeyComparator comparator;
explicit KeyComparator(const InternalKeyComparator& c) : comparator(c) { }
int operator()(const char* a, const char* b) const;
};
friend class MemTableIterator;
friend class MemTableBackwardIterator;
typedef SkipList<const char*, KeyComparator> Table;
KeyComparator comparator_;
int refs_;
Arena arena_;
Table table_;
// No copying allowed
MemTable(const MemTable&);
void operator=(const MemTable&);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_MEMTABLE_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// We recover the contents of the descriptor from the other files we find.
// (1) Any log files are first converted to tables
// (2) We scan every table to compute
// (a) smallest/largest for the table
// (b) largest sequence number in the table
// (3) We generate descriptor contents:
// - log number is set to zero
// - next-file-number is set to 1 + largest file number we found
// - last-sequence-number is set to largest sequence# found across
// all tables (see 2c)
// - compaction pointers are cleared
// - every table file is added at level 0
//
// Possible optimization 1:
// (a) Compute total size and use to pick appropriate max-level M
// (b) Sort tables by largest sequence# in the table
// (c) For each table: if it overlaps earlier table, place in level-0,
// else place in level-M.
// Possible optimization 2:
// Store per-table metadata (smallest, largest, largest-seq#, ...)
// in the table's meta section to speed up ScanTable.
#include "db/builder.h"
#include "db/db_impl.h"
#include "db/dbformat.h"
#include "db/filename.h"
#include "db/log_reader.h"
#include "db/log_writer.h"
#include "db/memtable.h"
#include "db/table_cache.h"
#include "db/version_edit.h"
#include "db/write_batch_internal.h"
#include "leveldb/comparator.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
namespace leveldb {
namespace {
class Repairer {
public:
Repairer(const std::string& dbname, const Options& options)
: dbname_(dbname),
env_(options.env),
icmp_(options.comparator),
ipolicy_(options.filter_policy),
options_(SanitizeOptions(dbname, &icmp_, &ipolicy_, options)),
owns_info_log_(options_.info_log != options.info_log),
owns_cache_(options_.block_cache != options.block_cache),
next_file_number_(1) {
// TableCache can be small since we expect each table to be opened once.
table_cache_ = new TableCache(dbname_, &options_, 10);
}
~Repairer() {
delete table_cache_;
if (owns_info_log_) {
delete options_.info_log;
}
if (owns_cache_) {
delete options_.block_cache;
}
}
Status Run() {
Status status = FindFiles();
if (status.ok()) {
ConvertLogFilesToTables();
ExtractMetaData();
status = WriteDescriptor();
}
if (status.ok()) {
unsigned long long bytes = 0;
for (size_t i = 0; i < tables_.size(); i++) {
bytes += tables_[i].meta.file_size;
}
Log(options_.info_log,
"**** Repaired leveldb %s; "
"recovered %d files; %llu bytes. "
"Some data may have been lost. "
"****",
dbname_.c_str(),
static_cast<int>(tables_.size()),
bytes);
}
return status;
}
private:
struct TableInfo {
FileMetaData meta;
SequenceNumber max_sequence;
};
std::string const dbname_;
Env* const env_;
InternalKeyComparator const icmp_;
InternalFilterPolicy const ipolicy_;
Options const options_;
bool owns_info_log_;
bool owns_cache_;
TableCache* table_cache_;
VersionEdit edit_;
std::vector<std::string> manifests_;
std::vector<uint64_t> table_numbers_;
std::vector<uint64_t> logs_;
std::vector<TableInfo> tables_;
uint64_t next_file_number_;
Status FindFiles() {
std::vector<std::string> filenames;
Status status = env_->GetChildren(dbname_, &filenames);
if (!status.ok()) {
return status;
}
if (filenames.empty()) {
return Status::IOError(dbname_, "repair found no files");
}
uint64_t number;
FileType type;
for (size_t i = 0; i < filenames.size(); i++) {
if (ParseFileName(filenames[i], &number, &type)) {
if (type == kDescriptorFile) {
manifests_.push_back(filenames[i]);
} else {
if (number + 1 > next_file_number_) {
next_file_number_ = number + 1;
}
if (type == kLogFile) {
logs_.push_back(number);
} else if (type == kTableFile) {
table_numbers_.push_back(number);
} else {
// Ignore other files
}
}
}
}
return status;
}
void ConvertLogFilesToTables() {
for (size_t i = 0; i < logs_.size(); i++) {
std::string logname = LogFileName(dbname_, logs_[i]);
Status status = ConvertLogToTable(logs_[i]);
if (!status.ok()) {
Log(options_.info_log, "Log #%llu: ignoring conversion error: %s",
(unsigned long long) logs_[i],
status.ToString().c_str());
}
ArchiveFile(logname);
}
}
Status ConvertLogToTable(uint64_t log) {
struct LogReporter : public log::Reader::Reporter {
Env* env;
Logger* info_log;
uint64_t lognum;
virtual void Corruption(size_t bytes, const Status& s) {
// We print error messages for corruption, but continue repairing.
Log(info_log, "Log #%llu: dropping %d bytes; %s",
(unsigned long long) lognum,
static_cast<int>(bytes),
s.ToString().c_str());
}
};
// Open the log file
std::string logname = LogFileName(dbname_, log);
SequentialFile* lfile;
Status status = env_->NewSequentialFile(logname, &lfile);
if (!status.ok()) {
return status;
}
// Create the log reader.
LogReporter reporter;
reporter.env = env_;
reporter.info_log = options_.info_log;
reporter.lognum = log;
// We intentially make log::Reader do checksumming so that
// corruptions cause entire commits to be skipped instead of
// propagating bad information (like overly large sequence
// numbers).
log::Reader reader(lfile, &reporter, false/*do not checksum*/,
0/*initial_offset*/);
// Read all the records and add to a memtable
std::string scratch;
Slice record;
WriteBatch batch;
MemTable* mem = new MemTable(icmp_);
mem->Ref();
int counter = 0;
while (reader.ReadRecord(&record, &scratch)) {
if (record.size() < 12) {
reporter.Corruption(
record.size(), Status::Corruption("log record too small"));
continue;
}
WriteBatchInternal::SetContents(&batch, record);
status = WriteBatchInternal::InsertInto(&batch, mem);
if (status.ok()) {
counter += WriteBatchInternal::Count(&batch);
} else {
Log(options_.info_log, "Log #%llu: ignoring %s",
(unsigned long long) log,
status.ToString().c_str());
status = Status::OK(); // Keep going with rest of file
}
}
delete lfile;
// Do not record a version edit for this conversion to a Table
// since ExtractMetaData() will also generate edits.
FileMetaData meta;
meta.number = next_file_number_++;
Iterator* iter = mem->NewIterator();
status = BuildTable(dbname_, env_, options_, table_cache_, iter, &meta);
delete iter;
mem->Unref();
mem = NULL;
if (status.ok()) {
if (meta.file_size > 0) {
table_numbers_.push_back(meta.number);
}
}
Log(options_.info_log, "Log #%llu: %d ops saved to Table #%llu %s",
(unsigned long long) log,
counter,
(unsigned long long) meta.number,
status.ToString().c_str());
return status;
}
void ExtractMetaData() {
std::vector<TableInfo> kept;
for (size_t i = 0; i < table_numbers_.size(); i++) {
TableInfo t;
t.meta.number = table_numbers_[i];
Status status = ScanTable(&t);
if (!status.ok()) {
std::string fname = TableFileName(dbname_, table_numbers_[i]);
Log(options_.info_log, "Table #%llu: ignoring %s",
(unsigned long long) table_numbers_[i],
status.ToString().c_str());
ArchiveFile(fname);
} else {
tables_.push_back(t);
}
}
}
Status ScanTable(TableInfo* t) {
std::string fname = TableFileName(dbname_, t->meta.number);
int counter = 0;
Status status = env_->GetFileSize(fname, &t->meta.file_size);
if (status.ok()) {
Iterator* iter = table_cache_->NewIterator(
ReadOptions(), t->meta.number, t->meta.file_size);
bool empty = true;
ParsedInternalKey parsed;
t->max_sequence = 0;
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
Slice key = iter->key();
if (!ParseInternalKey(key, &parsed)) {
Log(options_.info_log, "Table #%llu: unparsable key %s",
(unsigned long long) t->meta.number,
EscapeString(key).c_str());
continue;
}
counter++;
if (empty) {
empty = false;
t->meta.smallest.DecodeFrom(key);
}
t->meta.largest.DecodeFrom(key);
if (parsed.sequence > t->max_sequence) {
t->max_sequence = parsed.sequence;
}
}
if (!iter->status().ok()) {
status = iter->status();
}
delete iter;
}
Log(options_.info_log, "Table #%llu: %d entries %s",
(unsigned long long) t->meta.number,
counter,
status.ToString().c_str());
return status;
}
Status WriteDescriptor() {
std::string tmp = TempFileName(dbname_, 1);
WritableFile* file;
Status status = env_->NewWritableFile(tmp, &file);
if (!status.ok()) {
return status;
}
SequenceNumber max_sequence = 0;
for (size_t i = 0; i < tables_.size(); i++) {
if (max_sequence < tables_[i].max_sequence) {
max_sequence = tables_[i].max_sequence;
}
}
edit_.SetComparatorName(icmp_.user_comparator()->Name());
edit_.SetLogNumber(0);
edit_.SetNextFile(next_file_number_);
edit_.SetLastSequence(max_sequence);
for (size_t i = 0; i < tables_.size(); i++) {
// TODO(opt): separate out into multiple levels
const TableInfo& t = tables_[i];
edit_.AddFile(0, t.meta.number, t.meta.file_size,
t.meta.smallest, t.meta.largest);
}
//fprintf(stderr, "NewDescriptor:\n%s\n", edit_.DebugString().c_str());
{
log::Writer log(file);
std::string record;
edit_.EncodeTo(&record);
status = log.AddRecord(record);
}
if (status.ok()) {
status = file->Close();
}
delete file;
file = NULL;
if (!status.ok()) {
env_->DeleteFile(tmp);
} else {
// Discard older manifests
for (size_t i = 0; i < manifests_.size(); i++) {
ArchiveFile(dbname_ + "/" + manifests_[i]);
}
// Install new manifest
status = env_->RenameFile(tmp, DescriptorFileName(dbname_, 1));
if (status.ok()) {
status = SetCurrentFile(env_, dbname_, 1);
} else {
env_->DeleteFile(tmp);
}
}
return status;
}
void ArchiveFile(const std::string& fname) {
// Move into another directory. E.g., for
// dir/foo
// rename to
// dir/lost/foo
const char* slash = strrchr(fname.c_str(), '/');
std::string new_dir;
if (slash != NULL) {
new_dir.assign(fname.data(), slash - fname.data());
}
new_dir.append("/lost");
env_->CreateDir(new_dir); // Ignore error
std::string new_file = new_dir;
new_file.append("/");
new_file.append((slash == NULL) ? fname.c_str() : slash + 1);
Status s = env_->RenameFile(fname, new_file);
Log(options_.info_log, "Archiving %s: %s\n",
fname.c_str(), s.ToString().c_str());
}
};
} // namespace
Status RepairDB(const std::string& dbname, const Options& options) {
Repairer repairer(dbname, options);
return repairer.Run();
}
} // namespace leveldb

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src/leveldb/db/skiplist.h
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@ -1,379 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// Thread safety
// -------------
//
// Writes require external synchronization, most likely a mutex.
// Reads require a guarantee that the SkipList will not be destroyed
// while the read is in progress. Apart from that, reads progress
// without any internal locking or synchronization.
//
// Invariants:
//
// (1) Allocated nodes are never deleted until the SkipList is
// destroyed. This is trivially guaranteed by the code since we
// never delete any skip list nodes.
//
// (2) The contents of a Node except for the next/prev pointers are
// immutable after the Node has been linked into the SkipList.
// Only Insert() modifies the list, and it is careful to initialize
// a node and use release-stores to publish the nodes in one or
// more lists.
//
// ... prev vs. next pointer ordering ...
#include <assert.h>
#include <stdlib.h>
#include "port/port.h"
#include "util/arena.h"
#include "util/random.h"
namespace leveldb {
class Arena;
template<typename Key, class Comparator>
class SkipList {
private:
struct Node;
public:
// Create a new SkipList object that will use "cmp" for comparing keys,
// and will allocate memory using "*arena". Objects allocated in the arena
// must remain allocated for the lifetime of the skiplist object.
explicit SkipList(Comparator cmp, Arena* arena);
// Insert key into the list.
// REQUIRES: nothing that compares equal to key is currently in the list.
void Insert(const Key& key);
// Returns true iff an entry that compares equal to key is in the list.
bool Contains(const Key& key) const;
// Iteration over the contents of a skip list
class Iterator {
public:
// Initialize an iterator over the specified list.
// The returned iterator is not valid.
explicit Iterator(const SkipList* list);
// Returns true iff the iterator is positioned at a valid node.
bool Valid() const;
// Returns the key at the current position.
// REQUIRES: Valid()
const Key& key() const;
// Advances to the next position.
// REQUIRES: Valid()
void Next();
// Advances to the previous position.
// REQUIRES: Valid()
void Prev();
// Advance to the first entry with a key >= target
void Seek(const Key& target);
// Position at the first entry in list.
// Final state of iterator is Valid() iff list is not empty.
void SeekToFirst();
// Position at the last entry in list.
// Final state of iterator is Valid() iff list is not empty.
void SeekToLast();
private:
const SkipList* list_;
Node* node_;
// Intentionally copyable
};
private:
enum { kMaxHeight = 12 };
// Immutable after construction
Comparator const compare_;
Arena* const arena_; // Arena used for allocations of nodes
Node* const head_;
// Modified only by Insert(). Read racily by readers, but stale
// values are ok.
port::AtomicPointer max_height_; // Height of the entire list
inline int GetMaxHeight() const {
return static_cast<int>(
reinterpret_cast<intptr_t>(max_height_.NoBarrier_Load()));
}
// Read/written only by Insert().
Random rnd_;
Node* NewNode(const Key& key, int height);
int RandomHeight();
bool Equal(const Key& a, const Key& b) const { return (compare_(a, b) == 0); }
// Return true if key is greater than the data stored in "n"
bool KeyIsAfterNode(const Key& key, Node* n) const;
// Return the earliest node that comes at or after key.
// Return NULL if there is no such node.
//
// If prev is non-NULL, fills prev[level] with pointer to previous
// node at "level" for every level in [0..max_height_-1].
Node* FindGreaterOrEqual(const Key& key, Node** prev) const;
// Return the latest node with a key < key.
// Return head_ if there is no such node.
Node* FindLessThan(const Key& key) const;
// Return the last node in the list.
// Return head_ if list is empty.
Node* FindLast() const;
// No copying allowed
SkipList(const SkipList&);
void operator=(const SkipList&);
};
// Implementation details follow
template<typename Key, class Comparator>
struct SkipList<Key,Comparator>::Node {
explicit Node(const Key& k) : key(k) { }
Key const key;
// Accessors/mutators for links. Wrapped in methods so we can
// add the appropriate barriers as necessary.
Node* Next(int n) {
assert(n >= 0);
// Use an 'acquire load' so that we observe a fully initialized
// version of the returned Node.
return reinterpret_cast<Node*>(next_[n].Acquire_Load());
}
void SetNext(int n, Node* x) {
assert(n >= 0);
// Use a 'release store' so that anybody who reads through this
// pointer observes a fully initialized version of the inserted node.
next_[n].Release_Store(x);
}
// No-barrier variants that can be safely used in a few locations.
Node* NoBarrier_Next(int n) {
assert(n >= 0);
return reinterpret_cast<Node*>(next_[n].NoBarrier_Load());
}
void NoBarrier_SetNext(int n, Node* x) {
assert(n >= 0);
next_[n].NoBarrier_Store(x);
}
private:
// Array of length equal to the node height. next_[0] is lowest level link.
port::AtomicPointer next_[1];
};
template<typename Key, class Comparator>
typename SkipList<Key,Comparator>::Node*
SkipList<Key,Comparator>::NewNode(const Key& key, int height) {
char* mem = arena_->AllocateAligned(
sizeof(Node) + sizeof(port::AtomicPointer) * (height - 1));
return new (mem) Node(key);
}
template<typename Key, class Comparator>
inline SkipList<Key,Comparator>::Iterator::Iterator(const SkipList* list) {
list_ = list;
node_ = NULL;
}
template<typename Key, class Comparator>
inline bool SkipList<Key,Comparator>::Iterator::Valid() const {
return node_ != NULL;
}
template<typename Key, class Comparator>
inline const Key& SkipList<Key,Comparator>::Iterator::key() const {
assert(Valid());
return node_->key;
}
template<typename Key, class Comparator>
inline void SkipList<Key,Comparator>::Iterator::Next() {
assert(Valid());
node_ = node_->Next(0);
}
template<typename Key, class Comparator>
inline void SkipList<Key,Comparator>::Iterator::Prev() {
// Instead of using explicit "prev" links, we just search for the
// last node that falls before key.
assert(Valid());
node_ = list_->FindLessThan(node_->key);
if (node_ == list_->head_) {
node_ = NULL;
}
}
template<typename Key, class Comparator>
inline void SkipList<Key,Comparator>::Iterator::Seek(const Key& target) {
node_ = list_->FindGreaterOrEqual(target, NULL);
}
template<typename Key, class Comparator>
inline void SkipList<Key,Comparator>::Iterator::SeekToFirst() {
node_ = list_->head_->Next(0);
}
template<typename Key, class Comparator>
inline void SkipList<Key,Comparator>::Iterator::SeekToLast() {
node_ = list_->FindLast();
if (node_ == list_->head_) {
node_ = NULL;
}
}
template<typename Key, class Comparator>
int SkipList<Key,Comparator>::RandomHeight() {
// Increase height with probability 1 in kBranching
static const unsigned int kBranching = 4;
int height = 1;
while (height < kMaxHeight && ((rnd_.Next() % kBranching) == 0)) {
height++;
}
assert(height > 0);
assert(height <= kMaxHeight);
return height;
}
template<typename Key, class Comparator>
bool SkipList<Key,Comparator>::KeyIsAfterNode(const Key& key, Node* n) const {
// NULL n is considered infinite
return (n != NULL) && (compare_(n->key, key) < 0);
}
template<typename Key, class Comparator>
typename SkipList<Key,Comparator>::Node* SkipList<Key,Comparator>::FindGreaterOrEqual(const Key& key, Node** prev)
const {
Node* x = head_;
int level = GetMaxHeight() - 1;
while (true) {
Node* next = x->Next(level);
if (KeyIsAfterNode(key, next)) {
// Keep searching in this list
x = next;
} else {
if (prev != NULL) prev[level] = x;
if (level == 0) {
return next;
} else {
// Switch to next list
level--;
}
}
}
}
template<typename Key, class Comparator>
typename SkipList<Key,Comparator>::Node*
SkipList<Key,Comparator>::FindLessThan(const Key& key) const {
Node* x = head_;
int level = GetMaxHeight() - 1;
while (true) {
assert(x == head_ || compare_(x->key, key) < 0);
Node* next = x->Next(level);
if (next == NULL || compare_(next->key, key) >= 0) {
if (level == 0) {
return x;
} else {
// Switch to next list
level--;
}
} else {
x = next;
}
}
}
template<typename Key, class Comparator>
typename SkipList<Key,Comparator>::Node* SkipList<Key,Comparator>::FindLast()
const {
Node* x = head_;
int level = GetMaxHeight() - 1;
while (true) {
Node* next = x->Next(level);
if (next == NULL) {
if (level == 0) {
return x;
} else {
// Switch to next list
level--;
}
} else {
x = next;
}
}
}
template<typename Key, class Comparator>
SkipList<Key,Comparator>::SkipList(Comparator cmp, Arena* arena)
: compare_(cmp),
arena_(arena),
head_(NewNode(0 /* any key will do */, kMaxHeight)),
max_height_(reinterpret_cast<void*>(1)),
rnd_(0xdeadbeef) {
for (int i = 0; i < kMaxHeight; i++) {
head_->SetNext(i, NULL);
}
}
template<typename Key, class Comparator>
void SkipList<Key,Comparator>::Insert(const Key& key) {
// TODO(opt): We can use a barrier-free variant of FindGreaterOrEqual()
// here since Insert() is externally synchronized.
Node* prev[kMaxHeight];
Node* x = FindGreaterOrEqual(key, prev);
// Our data structure does not allow duplicate insertion
assert(x == NULL || !Equal(key, x->key));
int height = RandomHeight();
if (height > GetMaxHeight()) {
for (int i = GetMaxHeight(); i < height; i++) {
prev[i] = head_;
}
//fprintf(stderr, "Change height from %d to %d\n", max_height_, height);
// It is ok to mutate max_height_ without any synchronization
// with concurrent readers. A concurrent reader that observes
// the new value of max_height_ will see either the old value of
// new level pointers from head_ (NULL), or a new value set in
// the loop below. In the former case the reader will
// immediately drop to the next level since NULL sorts after all
// keys. In the latter case the reader will use the new node.
max_height_.NoBarrier_Store(reinterpret_cast<void*>(height));
}
x = NewNode(key, height);
for (int i = 0; i < height; i++) {
// NoBarrier_SetNext() suffices since we will add a barrier when
// we publish a pointer to "x" in prev[i].
x->NoBarrier_SetNext(i, prev[i]->NoBarrier_Next(i));
prev[i]->SetNext(i, x);
}
}
template<typename Key, class Comparator>
bool SkipList<Key,Comparator>::Contains(const Key& key) const {
Node* x = FindGreaterOrEqual(key, NULL);
if (x != NULL && Equal(key, x->key)) {
return true;
} else {
return false;
}
}
} // namespace leveldb

378
src/leveldb/db/skiplist_test.cc
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@ -1,378 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/skiplist.h"
#include <set>
#include "leveldb/env.h"
#include "util/arena.h"
#include "util/hash.h"
#include "util/random.h"
#include "util/testharness.h"
namespace leveldb {
typedef uint64_t Key;
struct Comparator {
int operator()(const Key& a, const Key& b) const {
if (a < b) {
return -1;
} else if (a > b) {
return +1;
} else {
return 0;
}
}
};
class SkipTest { };
TEST(SkipTest, Empty) {
Arena arena;
Comparator cmp;
SkipList<Key, Comparator> list(cmp, &arena);
ASSERT_TRUE(!list.Contains(10));
SkipList<Key, Comparator>::Iterator iter(&list);
ASSERT_TRUE(!iter.Valid());
iter.SeekToFirst();
ASSERT_TRUE(!iter.Valid());
iter.Seek(100);
ASSERT_TRUE(!iter.Valid());
iter.SeekToLast();
ASSERT_TRUE(!iter.Valid());
}
TEST(SkipTest, InsertAndLookup) {
const int N = 2000;
const int R = 5000;
Random rnd(1000);
std::set<Key> keys;
Arena arena;
Comparator cmp;
SkipList<Key, Comparator> list(cmp, &arena);
for (int i = 0; i < N; i++) {
Key key = rnd.Next() % R;
if (keys.insert(key).second) {
list.Insert(key);
}
}
for (int i = 0; i < R; i++) {
if (list.Contains(i)) {
ASSERT_EQ(keys.count(i), 1);
} else {
ASSERT_EQ(keys.count(i), 0);
}
}
// Simple iterator tests
{
SkipList<Key, Comparator>::Iterator iter(&list);
ASSERT_TRUE(!iter.Valid());
iter.Seek(0);
ASSERT_TRUE(iter.Valid());
ASSERT_EQ(*(keys.begin()), iter.key());
iter.SeekToFirst();
ASSERT_TRUE(iter.Valid());
ASSERT_EQ(*(keys.begin()), iter.key());
iter.SeekToLast();
ASSERT_TRUE(iter.Valid());
ASSERT_EQ(*(keys.rbegin()), iter.key());
}
// Forward iteration test
for (int i = 0; i < R; i++) {
SkipList<Key, Comparator>::Iterator iter(&list);
iter.Seek(i);
// Compare against model iterator
std::set<Key>::iterator model_iter = keys.lower_bound(i);
for (int j = 0; j < 3; j++) {
if (model_iter == keys.end()) {
ASSERT_TRUE(!iter.Valid());
break;
} else {
ASSERT_TRUE(iter.Valid());
ASSERT_EQ(*model_iter, iter.key());
++model_iter;
iter.Next();
}
}
}
// Backward iteration test
{
SkipList<Key, Comparator>::Iterator iter(&list);
iter.SeekToLast();
// Compare against model iterator
for (std::set<Key>::reverse_iterator model_iter = keys.rbegin();
model_iter != keys.rend();
++model_iter) {
ASSERT_TRUE(iter.Valid());
ASSERT_EQ(*model_iter, iter.key());
iter.Prev();
}
ASSERT_TRUE(!iter.Valid());
}
}
// We want to make sure that with a single writer and multiple
// concurrent readers (with no synchronization other than when a
// reader's iterator is created), the reader always observes all the
// data that was present in the skip list when the iterator was
// constructor. Because insertions are happening concurrently, we may
// also observe new values that were inserted since the iterator was
// constructed, but we should never miss any values that were present
// at iterator construction time.
//
// We generate multi-part keys:
// <key,gen,hash>
// where:
// key is in range [0..K-1]
// gen is a generation number for key
// hash is hash(key,gen)
//
// The insertion code picks a random key, sets gen to be 1 + the last
// generation number inserted for that key, and sets hash to Hash(key,gen).
//
// At the beginning of a read, we snapshot the last inserted
// generation number for each key. We then iterate, including random
// calls to Next() and Seek(). For every key we encounter, we
// check that it is either expected given the initial snapshot or has
// been concurrently added since the iterator started.
class ConcurrentTest {
private:
static const uint32_t K = 4;
static uint64_t key(Key key) { return (key >> 40); }
static uint64_t gen(Key key) { return (key >> 8) & 0xffffffffu; }
static uint64_t hash(Key key) { return key & 0xff; }
static uint64_t HashNumbers(uint64_t k, uint64_t g) {
uint64_t data[2] = { k, g };
return Hash(reinterpret_cast<char*>(data), sizeof(data), 0);
}
static Key MakeKey(uint64_t k, uint64_t g) {
assert(sizeof(Key) == sizeof(uint64_t));
assert(k <= K); // We sometimes pass K to seek to the end of the skiplist
assert(g <= 0xffffffffu);
return ((k << 40) | (g << 8) | (HashNumbers(k, g) & 0xff));
}
static bool IsValidKey(Key k) {
return hash(k) == (HashNumbers(key(k), gen(k)) & 0xff);
}
static Key RandomTarget(Random* rnd) {
switch (rnd->Next() % 10) {
case 0:
// Seek to beginning
return MakeKey(0, 0);
case 1:
// Seek to end
return MakeKey(K, 0);
default:
// Seek to middle
return MakeKey(rnd->Next() % K, 0);
}
}
// Per-key generation
struct State {
port::AtomicPointer generation[K];
void Set(int k, intptr_t v) {
generation[k].Release_Store(reinterpret_cast<void*>(v));
}
intptr_t Get(int k) {
return reinterpret_cast<intptr_t>(generation[k].Acquire_Load());
}
State() {
for (int k = 0; k < K; k++) {
Set(k, 0);
}
}
};
// Current state of the test
State current_;
Arena arena_;
// SkipList is not protected by mu_. We just use a single writer
// thread to modify it.
SkipList<Key, Comparator> list_;
public:
ConcurrentTest() : list_(Comparator(), &arena_) { }
// REQUIRES: External synchronization
void WriteStep(Random* rnd) {
const uint32_t k = rnd->Next() % K;
const intptr_t g = current_.Get(k) + 1;
const Key key = MakeKey(k, g);
list_.Insert(key);
current_.Set(k, g);
}
void ReadStep(Random* rnd) {
// Remember the initial committed state of the skiplist.
State initial_state;
for (int k = 0; k < K; k++) {
initial_state.Set(k, current_.Get(k));
}
Key pos = RandomTarget(rnd);
SkipList<Key, Comparator>::Iterator iter(&list_);
iter.Seek(pos);
while (true) {
Key current;
if (!iter.Valid()) {
current = MakeKey(K, 0);
} else {
current = iter.key();
ASSERT_TRUE(IsValidKey(current)) << current;
}
ASSERT_LE(pos, current) << "should not go backwards";
// Verify that everything in [pos,current) was not present in
// initial_state.
while (pos < current) {
ASSERT_LT(key(pos), K) << pos;
// Note that generation 0 is never inserted, so it is ok if
// <*,0,*> is missing.
ASSERT_TRUE((gen(pos) == 0) ||
(gen(pos) > initial_state.Get(key(pos)))
) << "key: " << key(pos)
<< "; gen: " << gen(pos)
<< "; initgen: "
<< initial_state.Get(key(pos));
// Advance to next key in the valid key space
if (key(pos) < key(current)) {
pos = MakeKey(key(pos) + 1, 0);
} else {
pos = MakeKey(key(pos), gen(pos) + 1);
}
}
if (!iter.Valid()) {
break;
}
if (rnd->Next() % 2) {
iter.Next();
pos = MakeKey(key(pos), gen(pos) + 1);
} else {
Key new_target = RandomTarget(rnd);
if (new_target > pos) {
pos = new_target;
iter.Seek(new_target);
}
}
}
}
};
const uint32_t ConcurrentTest::K;
// Simple test that does single-threaded testing of the ConcurrentTest
// scaffolding.
TEST(SkipTest, ConcurrentWithoutThreads) {
ConcurrentTest test;
Random rnd(test::RandomSeed());
for (int i = 0; i < 10000; i++) {
test.ReadStep(&rnd);
test.WriteStep(&rnd);
}
}
class TestState {
public:
ConcurrentTest t_;
int seed_;
port::AtomicPointer quit_flag_;
enum ReaderState {
STARTING,
RUNNING,
DONE
};
explicit TestState(int s)
: seed_(s),
quit_flag_(NULL),
state_(STARTING),
state_cv_(&mu_) {}
void Wait(ReaderState s) {
mu_.Lock();
while (state_ != s) {
state_cv_.Wait();
}
mu_.Unlock();
}
void Change(ReaderState s) {
mu_.Lock();
state_ = s;
state_cv_.Signal();
mu_.Unlock();
}
private:
port::Mutex mu_;
ReaderState state_;
port::CondVar state_cv_;
};
static void ConcurrentReader(void* arg) {
TestState* state = reinterpret_cast<TestState*>(arg);
Random rnd(state->seed_);
int64_t reads = 0;
state->Change(TestState::RUNNING);
while (!state->quit_flag_.Acquire_Load()) {
state->t_.ReadStep(&rnd);
++reads;
}
state->Change(TestState::DONE);
}
static void RunConcurrent(int run) {
const int seed = test::RandomSeed() + (run * 100);
Random rnd(seed);
const int N = 1000;
const int kSize = 1000;
for (int i = 0; i < N; i++) {
if ((i % 100) == 0) {
fprintf(stderr, "Run %d of %d\n", i, N);
}
TestState state(seed + 1);
Env::Default()->Schedule(ConcurrentReader, &state);
state.Wait(TestState::RUNNING);
for (int i = 0; i < kSize; i++) {
state.t_.WriteStep(&rnd);
}
state.quit_flag_.Release_Store(&state); // Any non-NULL arg will do
state.Wait(TestState::DONE);
}
}
TEST(SkipTest, Concurrent1) { RunConcurrent(1); }
TEST(SkipTest, Concurrent2) { RunConcurrent(2); }
TEST(SkipTest, Concurrent3) { RunConcurrent(3); }
TEST(SkipTest, Concurrent4) { RunConcurrent(4); }
TEST(SkipTest, Concurrent5) { RunConcurrent(5); }
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_SNAPSHOT_H_
#define STORAGE_LEVELDB_DB_SNAPSHOT_H_
#include "leveldb/db.h"
namespace leveldb {
class SnapshotList;
// Snapshots are kept in a doubly-linked list in the DB.
// Each SnapshotImpl corresponds to a particular sequence number.
class SnapshotImpl : public Snapshot {
public:
SequenceNumber number_; // const after creation
private:
friend class SnapshotList;
// SnapshotImpl is kept in a doubly-linked circular list
SnapshotImpl* prev_;
SnapshotImpl* next_;
SnapshotList* list_; // just for sanity checks
};
class SnapshotList {
public:
SnapshotList() {
list_.prev_ = &list_;
list_.next_ = &list_;
}
bool empty() const { return list_.next_ == &list_; }
SnapshotImpl* oldest() const { assert(!empty()); return list_.next_; }
SnapshotImpl* newest() const { assert(!empty()); return list_.prev_; }
const SnapshotImpl* New(SequenceNumber seq) {
SnapshotImpl* s = new SnapshotImpl;
s->number_ = seq;
s->list_ = this;
s->next_ = &list_;
s->prev_ = list_.prev_;
s->prev_->next_ = s;
s->next_->prev_ = s;
return s;
}
void Delete(const SnapshotImpl* s) {
assert(s->list_ == this);
s->prev_->next_ = s->next_;
s->next_->prev_ = s->prev_;
delete s;
}
private:
// Dummy head of doubly-linked list of snapshots
SnapshotImpl list_;
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_SNAPSHOT_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/table_cache.h"
#include "db/filename.h"
#include "leveldb/env.h"
#include "leveldb/table.h"
#include "util/coding.h"
namespace leveldb {
struct TableAndFile {
RandomAccessFile* file;
Table* table;
};
static void DeleteEntry(const Slice& key, void* value) {
TableAndFile* tf = reinterpret_cast<TableAndFile*>(value);
delete tf->table;
delete tf->file;
delete tf;
}
static void UnrefEntry(void* arg1, void* arg2) {
Cache* cache = reinterpret_cast<Cache*>(arg1);
Cache::Handle* h = reinterpret_cast<Cache::Handle*>(arg2);
cache->Release(h);
}
TableCache::TableCache(const std::string& dbname,
const Options* options,
int entries)
: env_(options->env),
dbname_(dbname),
options_(options),
cache_(NewLRUCache(entries)) {
}
TableCache::~TableCache() {
delete cache_;
}
Status TableCache::FindTable(uint64_t file_number, uint64_t file_size,
Cache::Handle** handle) {
Status s;
char buf[sizeof(file_number)];
EncodeFixed64(buf, file_number);
Slice key(buf, sizeof(buf));
*handle = cache_->Lookup(key);
if (*handle == NULL) {
std::string fname = TableFileName(dbname_, file_number);
RandomAccessFile* file = NULL;
Table* table = NULL;
s = env_->NewRandomAccessFile(fname, &file);
if (s.ok()) {
s = Table::Open(*options_, file, file_size, &table);
}
if (!s.ok()) {
assert(table == NULL);
delete file;
// We do not cache error results so that if the error is transient,
// or somebody repairs the file, we recover automatically.
} else {
TableAndFile* tf = new TableAndFile;
tf->file = file;
tf->table = table;
*handle = cache_->Insert(key, tf, 1, &DeleteEntry);
}
}
return s;
}
Iterator* TableCache::NewIterator(const ReadOptions& options,
uint64_t file_number,
uint64_t file_size,
Table** tableptr) {
if (tableptr != NULL) {
*tableptr = NULL;
}
Cache::Handle* handle = NULL;
Status s = FindTable(file_number, file_size, &handle);
if (!s.ok()) {
return NewErrorIterator(s);
}
Table* table = reinterpret_cast<TableAndFile*>(cache_->Value(handle))->table;
Iterator* result = table->NewIterator(options);
result->RegisterCleanup(&UnrefEntry, cache_, handle);
if (tableptr != NULL) {
*tableptr = table;
}
return result;
}
Status TableCache::Get(const ReadOptions& options,
uint64_t file_number,
uint64_t file_size,
const Slice& k,
void* arg,
void (*saver)(void*, const Slice&, const Slice&)) {
Cache::Handle* handle = NULL;
Status s = FindTable(file_number, file_size, &handle);
if (s.ok()) {
Table* t = reinterpret_cast<TableAndFile*>(cache_->Value(handle))->table;
s = t->InternalGet(options, k, arg, saver);
cache_->Release(handle);
}
return s;
}
void TableCache::Evict(uint64_t file_number) {
char buf[sizeof(file_number)];
EncodeFixed64(buf, file_number);
cache_->Erase(Slice(buf, sizeof(buf)));
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// Thread-safe (provides internal synchronization)
#ifndef STORAGE_LEVELDB_DB_TABLE_CACHE_H_
#define STORAGE_LEVELDB_DB_TABLE_CACHE_H_
#include <string>
#include <stdint.h>
#include "db/dbformat.h"
#include "leveldb/cache.h"
#include "leveldb/table.h"
#include "port/port.h"
namespace leveldb {
class Env;
class TableCache {
public:
TableCache(const std::string& dbname, const Options* options, int entries);
~TableCache();
// Return an iterator for the specified file number (the corresponding
// file length must be exactly "file_size" bytes). If "tableptr" is
// non-NULL, also sets "*tableptr" to point to the Table object
// underlying the returned iterator, or NULL if no Table object underlies
// the returned iterator. The returned "*tableptr" object is owned by
// the cache and should not be deleted, and is valid for as long as the
// returned iterator is live.
Iterator* NewIterator(const ReadOptions& options,
uint64_t file_number,
uint64_t file_size,
Table** tableptr = NULL);
// If a seek to internal key "k" in specified file finds an entry,
// call (*handle_result)(arg, found_key, found_value).
Status Get(const ReadOptions& options,
uint64_t file_number,
uint64_t file_size,
const Slice& k,
void* arg,
void (*handle_result)(void*, const Slice&, const Slice&));
// Evict any entry for the specified file number
void Evict(uint64_t file_number);
private:
Env* const env_;
const std::string dbname_;
const Options* options_;
Cache* cache_;
Status FindTable(uint64_t file_number, uint64_t file_size, Cache::Handle**);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_TABLE_CACHE_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/version_edit.h"
#include "db/version_set.h"
#include "util/coding.h"
namespace leveldb {
// Tag numbers for serialized VersionEdit. These numbers are written to
// disk and should not be changed.
enum Tag {
kComparator = 1,
kLogNumber = 2,
kNextFileNumber = 3,
kLastSequence = 4,
kCompactPointer = 5,
kDeletedFile = 6,
kNewFile = 7,
// 8 was used for large value refs
kPrevLogNumber = 9
};
void VersionEdit::Clear() {
comparator_.clear();
log_number_ = 0;
prev_log_number_ = 0;
last_sequence_ = 0;
next_file_number_ = 0;
has_comparator_ = false;
has_log_number_ = false;
has_prev_log_number_ = false;
has_next_file_number_ = false;
has_last_sequence_ = false;
deleted_files_.clear();
new_files_.clear();
}
void VersionEdit::EncodeTo(std::string* dst) const {
if (has_comparator_) {
PutVarint32(dst, kComparator);
PutLengthPrefixedSlice(dst, comparator_);
}
if (has_log_number_) {
PutVarint32(dst, kLogNumber);
PutVarint64(dst, log_number_);
}
if (has_prev_log_number_) {
PutVarint32(dst, kPrevLogNumber);
PutVarint64(dst, prev_log_number_);
}
if (has_next_file_number_) {
PutVarint32(dst, kNextFileNumber);
PutVarint64(dst, next_file_number_);
}
if (has_last_sequence_) {
PutVarint32(dst, kLastSequence);
PutVarint64(dst, last_sequence_);
}
for (size_t i = 0; i < compact_pointers_.size(); i++) {
PutVarint32(dst, kCompactPointer);
PutVarint32(dst, compact_pointers_[i].first); // level
PutLengthPrefixedSlice(dst, compact_pointers_[i].second.Encode());
}
for (DeletedFileSet::const_iterator iter = deleted_files_.begin();
iter != deleted_files_.end();
++iter) {
PutVarint32(dst, kDeletedFile);
PutVarint32(dst, iter->first); // level
PutVarint64(dst, iter->second); // file number
}
for (size_t i = 0; i < new_files_.size(); i++) {
const FileMetaData& f = new_files_[i].second;
PutVarint32(dst, kNewFile);
PutVarint32(dst, new_files_[i].first); // level
PutVarint64(dst, f.number);
PutVarint64(dst, f.file_size);
PutLengthPrefixedSlice(dst, f.smallest.Encode());
PutLengthPrefixedSlice(dst, f.largest.Encode());
}
}
static bool GetInternalKey(Slice* input, InternalKey* dst) {
Slice str;
if (GetLengthPrefixedSlice(input, &str)) {
dst->DecodeFrom(str);
return true;
} else {
return false;
}
}
static bool GetLevel(Slice* input, int* level) {
uint32_t v;
if (GetVarint32(input, &v) &&
v < config::kNumLevels) {
*level = v;
return true;
} else {
return false;
}
}
Status VersionEdit::DecodeFrom(const Slice& src) {
Clear();
Slice input = src;
const char* msg = NULL;
uint32_t tag;
// Temporary storage for parsing
int level;
uint64_t number;
FileMetaData f;
Slice str;
InternalKey key;
while (msg == NULL && GetVarint32(&input, &tag)) {
switch (tag) {
case kComparator:
if (GetLengthPrefixedSlice(&input, &str)) {
comparator_ = str.ToString();
has_comparator_ = true;
} else {
msg = "comparator name";
}
break;
case kLogNumber:
if (GetVarint64(&input, &log_number_)) {
has_log_number_ = true;
} else {
msg = "log number";
}
break;
case kPrevLogNumber:
if (GetVarint64(&input, &prev_log_number_)) {
has_prev_log_number_ = true;
} else {
msg = "previous log number";
}
break;
case kNextFileNumber:
if (GetVarint64(&input, &next_file_number_)) {
has_next_file_number_ = true;
} else {
msg = "next file number";
}
break;
case kLastSequence:
if (GetVarint64(&input, &last_sequence_)) {
has_last_sequence_ = true;
} else {
msg = "last sequence number";
}
break;
case kCompactPointer:
if (GetLevel(&input, &level) &&
GetInternalKey(&input, &key)) {
compact_pointers_.push_back(std::make_pair(level, key));
} else {
msg = "compaction pointer";
}
break;
case kDeletedFile:
if (GetLevel(&input, &level) &&
GetVarint64(&input, &number)) {
deleted_files_.insert(std::make_pair(level, number));
} else {
msg = "deleted file";
}
break;
case kNewFile:
if (GetLevel(&input, &level) &&
GetVarint64(&input, &f.number) &&
GetVarint64(&input, &f.file_size) &&
GetInternalKey(&input, &f.smallest) &&
GetInternalKey(&input, &f.largest)) {
new_files_.push_back(std::make_pair(level, f));
} else {
msg = "new-file entry";
}
break;
default:
msg = "unknown tag";
break;
}
}
if (msg == NULL && !input.empty()) {
msg = "invalid tag";
}
Status result;
if (msg != NULL) {
result = Status::Corruption("VersionEdit", msg);
}
return result;
}
std::string VersionEdit::DebugString() const {
std::string r;
r.append("VersionEdit {");
if (has_comparator_) {
r.append("\n Comparator: ");
r.append(comparator_);
}
if (has_log_number_) {
r.append("\n LogNumber: ");
AppendNumberTo(&r, log_number_);
}
if (has_prev_log_number_) {
r.append("\n PrevLogNumber: ");
AppendNumberTo(&r, prev_log_number_);
}
if (has_next_file_number_) {
r.append("\n NextFile: ");
AppendNumberTo(&r, next_file_number_);
}
if (has_last_sequence_) {
r.append("\n LastSeq: ");
AppendNumberTo(&r, last_sequence_);
}
for (size_t i = 0; i < compact_pointers_.size(); i++) {
r.append("\n CompactPointer: ");
AppendNumberTo(&r, compact_pointers_[i].first);
r.append(" ");
r.append(compact_pointers_[i].second.DebugString());
}
for (DeletedFileSet::const_iterator iter = deleted_files_.begin();
iter != deleted_files_.end();
++iter) {
r.append("\n DeleteFile: ");
AppendNumberTo(&r, iter->first);
r.append(" ");
AppendNumberTo(&r, iter->second);
}
for (size_t i = 0; i < new_files_.size(); i++) {
const FileMetaData& f = new_files_[i].second;
r.append("\n AddFile: ");
AppendNumberTo(&r, new_files_[i].first);
r.append(" ");
AppendNumberTo(&r, f.number);
r.append(" ");
AppendNumberTo(&r, f.file_size);
r.append(" ");
r.append(f.smallest.DebugString());
r.append(" .. ");
r.append(f.largest.DebugString());
}
r.append("\n}\n");
return r;
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_VERSION_EDIT_H_
#define STORAGE_LEVELDB_DB_VERSION_EDIT_H_
#include <set>
#include <utility>
#include <vector>
#include "db/dbformat.h"
namespace leveldb {
class VersionSet;
struct FileMetaData {
int refs;
int allowed_seeks; // Seeks allowed until compaction
uint64_t number;
uint64_t file_size; // File size in bytes
InternalKey smallest; // Smallest internal key served by table
InternalKey largest; // Largest internal key served by table
FileMetaData() : refs(0), allowed_seeks(1 << 30), file_size(0) { }
};
class VersionEdit {
public:
VersionEdit() { Clear(); }
~VersionEdit() { }
void Clear();
void SetComparatorName(const Slice& name) {
has_comparator_ = true;
comparator_ = name.ToString();
}
void SetLogNumber(uint64_t num) {
has_log_number_ = true;
log_number_ = num;
}
void SetPrevLogNumber(uint64_t num) {
has_prev_log_number_ = true;
prev_log_number_ = num;
}
void SetNextFile(uint64_t num) {
has_next_file_number_ = true;
next_file_number_ = num;
}
void SetLastSequence(SequenceNumber seq) {
has_last_sequence_ = true;
last_sequence_ = seq;
}
void SetCompactPointer(int level, const InternalKey& key) {
compact_pointers_.push_back(std::make_pair(level, key));
}
// Add the specified file at the specified number.
// REQUIRES: This version has not been saved (see VersionSet::SaveTo)
// REQUIRES: "smallest" and "largest" are smallest and largest keys in file
void AddFile(int level, uint64_t file,
uint64_t file_size,
const InternalKey& smallest,
const InternalKey& largest) {
FileMetaData f;
f.number = file;
f.file_size = file_size;
f.smallest = smallest;
f.largest = largest;
new_files_.push_back(std::make_pair(level, f));
}
// Delete the specified "file" from the specified "level".
void DeleteFile(int level, uint64_t file) {
deleted_files_.insert(std::make_pair(level, file));
}
void EncodeTo(std::string* dst) const;
Status DecodeFrom(const Slice& src);
std::string DebugString() const;
private:
friend class VersionSet;
typedef std::set< std::pair<int, uint64_t> > DeletedFileSet;
std::string comparator_;
uint64_t log_number_;
uint64_t prev_log_number_;
uint64_t next_file_number_;
SequenceNumber last_sequence_;
bool has_comparator_;
bool has_log_number_;
bool has_prev_log_number_;
bool has_next_file_number_;
bool has_last_sequence_;
std::vector< std::pair<int, InternalKey> > compact_pointers_;
DeletedFileSet deleted_files_;
std::vector< std::pair<int, FileMetaData> > new_files_;
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_VERSION_EDIT_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/version_edit.h"
#include "util/testharness.h"
namespace leveldb {
static void TestEncodeDecode(const VersionEdit& edit) {
std::string encoded, encoded2;
edit.EncodeTo(&encoded);
VersionEdit parsed;
Status s = parsed.DecodeFrom(encoded);
ASSERT_TRUE(s.ok()) << s.ToString();
parsed.EncodeTo(&encoded2);
ASSERT_EQ(encoded, encoded2);
}
class VersionEditTest { };
TEST(VersionEditTest, EncodeDecode) {
static const uint64_t kBig = 1ull << 50;
VersionEdit edit;
for (int i = 0; i < 4; i++) {
TestEncodeDecode(edit);
edit.AddFile(3, kBig + 300 + i, kBig + 400 + i,
InternalKey("foo", kBig + 500 + i, kTypeValue),
InternalKey("zoo", kBig + 600 + i, kTypeDeletion));
edit.DeleteFile(4, kBig + 700 + i);
edit.SetCompactPointer(i, InternalKey("x", kBig + 900 + i, kTypeValue));
}
edit.SetComparatorName("foo");
edit.SetLogNumber(kBig + 100);
edit.SetNextFile(kBig + 200);
edit.SetLastSequence(kBig + 1000);
TestEncodeDecode(edit);
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// The representation of a DBImpl consists of a set of Versions. The
// newest version is called "current". Older versions may be kept
// around to provide a consistent view to live iterators.
//
// Each Version keeps track of a set of Table files per level. The
// entire set of versions is maintained in a VersionSet.
//
// Version,VersionSet are thread-compatible, but require external
// synchronization on all accesses.
#ifndef STORAGE_LEVELDB_DB_VERSION_SET_H_
#define STORAGE_LEVELDB_DB_VERSION_SET_H_
#include <map>
#include <set>
#include <vector>
#include "db/dbformat.h"
#include "db/version_edit.h"
#include "port/port.h"
#include "port/thread_annotations.h"
namespace leveldb {
namespace log { class Writer; }
class Compaction;
class Iterator;
class MemTable;
class TableBuilder;
class TableCache;
class Version;
class VersionSet;
class WritableFile;
// Return the smallest index i such that files[i]->largest >= key.
// Return files.size() if there is no such file.
// REQUIRES: "files" contains a sorted list of non-overlapping files.
extern int FindFile(const InternalKeyComparator& icmp,
const std::vector<FileMetaData*>& files,
const Slice& key);
// Returns true iff some file in "files" overlaps the user key range
// [*smallest,*largest].
// smallest==NULL represents a key smaller than all keys in the DB.
// largest==NULL represents a key largest than all keys in the DB.
// REQUIRES: If disjoint_sorted_files, files[] contains disjoint ranges
// in sorted order.
extern bool SomeFileOverlapsRange(
const InternalKeyComparator& icmp,
bool disjoint_sorted_files,
const std::vector<FileMetaData*>& files,
const Slice* smallest_user_key,
const Slice* largest_user_key);
class Version {
public:
// Append to *iters a sequence of iterators that will
// yield the contents of this Version when merged together.
// REQUIRES: This version has been saved (see VersionSet::SaveTo)
void AddIterators(const ReadOptions&, std::vector<Iterator*>* iters);
// Lookup the value for key. If found, store it in *val and
// return OK. Else return a non-OK status. Fills *stats.
// REQUIRES: lock is not held
struct GetStats {
FileMetaData* seek_file;
int seek_file_level;
};
Status Get(const ReadOptions&, const LookupKey& key, std::string* val,
GetStats* stats);
// Adds "stats" into the current state. Returns true if a new
// compaction may need to be triggered, false otherwise.
// REQUIRES: lock is held
bool UpdateStats(const GetStats& stats);
// Reference count management (so Versions do not disappear out from
// under live iterators)
void Ref();
void Unref();
void GetOverlappingInputs(
int level,
const InternalKey* begin, // NULL means before all keys
const InternalKey* end, // NULL means after all keys
std::vector<FileMetaData*>* inputs);
// Returns true iff some file in the specified level overlaps
// some part of [*smallest_user_key,*largest_user_key].
// smallest_user_key==NULL represents a key smaller than all keys in the DB.
// largest_user_key==NULL represents a key largest than all keys in the DB.
bool OverlapInLevel(int level,
const Slice* smallest_user_key,
const Slice* largest_user_key);
// Return the level at which we should place a new memtable compaction
// result that covers the range [smallest_user_key,largest_user_key].
int PickLevelForMemTableOutput(const Slice& smallest_user_key,
const Slice& largest_user_key);
int NumFiles(int level) const { return files_[level].size(); }
// Return a human readable string that describes this version's contents.
std::string DebugString() const;
private:
friend class Compaction;
friend class VersionSet;
class LevelFileNumIterator;
Iterator* NewConcatenatingIterator(const ReadOptions&, int level) const;
VersionSet* vset_; // VersionSet to which this Version belongs
Version* next_; // Next version in linked list
Version* prev_; // Previous version in linked list
int refs_; // Number of live refs to this version
// List of files per level
std::vector<FileMetaData*> files_[config::kNumLevels];
// Next file to compact based on seek stats.
FileMetaData* file_to_compact_;
int file_to_compact_level_;
// Level that should be compacted next and its compaction score.
// Score < 1 means compaction is not strictly needed. These fields
// are initialized by Finalize().
double compaction_score_;
int compaction_level_;
explicit Version(VersionSet* vset)
: vset_(vset), next_(this), prev_(this), refs_(0),
file_to_compact_(NULL),
file_to_compact_level_(-1),
compaction_score_(-1),
compaction_level_(-1) {
}
~Version();
// No copying allowed
Version(const Version&);
void operator=(const Version&);
};
class VersionSet {
public:
VersionSet(const std::string& dbname,
const Options* options,
TableCache* table_cache,
const InternalKeyComparator*);
~VersionSet();
// Apply *edit to the current version to form a new descriptor that
// is both saved to persistent state and installed as the new
// current version. Will release *mu while actually writing to the file.
// REQUIRES: *mu is held on entry.
// REQUIRES: no other thread concurrently calls LogAndApply()
Status LogAndApply(VersionEdit* edit, port::Mutex* mu)
EXCLUSIVE_LOCKS_REQUIRED(mu);
// Recover the last saved descriptor from persistent storage.
Status Recover();
// Return the current version.
Version* current() const { return current_; }
// Return the current manifest file number
uint64_t ManifestFileNumber() const { return manifest_file_number_; }
// Allocate and return a new file number
uint64_t NewFileNumber() { return next_file_number_++; }
// Arrange to reuse "file_number" unless a newer file number has
// already been allocated.
// REQUIRES: "file_number" was returned by a call to NewFileNumber().
void ReuseFileNumber(uint64_t file_number) {
if (next_file_number_ == file_number + 1) {
next_file_number_ = file_number;
}
}
// Return the number of Table files at the specified level.
int NumLevelFiles(int level) const;
// Return the combined file size of all files at the specified level.
int64_t NumLevelBytes(int level) const;
// Return the last sequence number.
uint64_t LastSequence() const { return last_sequence_; }
// Set the last sequence number to s.
void SetLastSequence(uint64_t s) {
assert(s >= last_sequence_);
last_sequence_ = s;
}
// Mark the specified file number as used.
void MarkFileNumberUsed(uint64_t number);
// Return the current log file number.
uint64_t LogNumber() const { return log_number_; }
// Return the log file number for the log file that is currently
// being compacted, or zero if there is no such log file.
uint64_t PrevLogNumber() const { return prev_log_number_; }
// Pick level and inputs for a new compaction.
// Returns NULL if there is no compaction to be done.
// Otherwise returns a pointer to a heap-allocated object that
// describes the compaction. Caller should delete the result.
Compaction* PickCompaction();
// Return a compaction object for compacting the range [begin,end] in
// the specified level. Returns NULL if there is nothing in that
// level that overlaps the specified range. Caller should delete
// the result.
Compaction* CompactRange(
int level,
const InternalKey* begin,
const InternalKey* end);
// Return the maximum overlapping data (in bytes) at next level for any
// file at a level >= 1.
int64_t MaxNextLevelOverlappingBytes();
// Create an iterator that reads over the compaction inputs for "*c".
// The caller should delete the iterator when no longer needed.
Iterator* MakeInputIterator(Compaction* c);
// Returns true iff some level needs a compaction.
bool NeedsCompaction() const {
Version* v = current_;
return (v->compaction_score_ >= 1) || (v->file_to_compact_ != NULL);
}
// Add all files listed in any live version to *live.
// May also mutate some internal state.
void AddLiveFiles(std::set<uint64_t>* live);
// Return the approximate offset in the database of the data for
// "key" as of version "v".
uint64_t ApproximateOffsetOf(Version* v, const InternalKey& key);
// Return a human-readable short (single-line) summary of the number
// of files per level. Uses *scratch as backing store.
struct LevelSummaryStorage {
char buffer[100];
};
const char* LevelSummary(LevelSummaryStorage* scratch) const;
private:
class Builder;
friend class Compaction;
friend class Version;
void Finalize(Version* v);
void GetRange(const std::vector<FileMetaData*>& inputs,
InternalKey* smallest,
InternalKey* largest);
void GetRange2(const std::vector<FileMetaData*>& inputs1,
const std::vector<FileMetaData*>& inputs2,
InternalKey* smallest,
InternalKey* largest);
void SetupOtherInputs(Compaction* c);
// Save current contents to *log
Status WriteSnapshot(log::Writer* log);
void AppendVersion(Version* v);
Env* const env_;
const std::string dbname_;
const Options* const options_;
TableCache* const table_cache_;
const InternalKeyComparator icmp_;
uint64_t next_file_number_;
uint64_t manifest_file_number_;
uint64_t last_sequence_;
uint64_t log_number_;
uint64_t prev_log_number_; // 0 or backing store for memtable being compacted
// Opened lazily
WritableFile* descriptor_file_;
log::Writer* descriptor_log_;
Version dummy_versions_; // Head of circular doubly-linked list of versions.
Version* current_; // == dummy_versions_.prev_
// Per-level key at which the next compaction at that level should start.
// Either an empty string, or a valid InternalKey.
std::string compact_pointer_[config::kNumLevels];
// No copying allowed
VersionSet(const VersionSet&);
void operator=(const VersionSet&);
};
// A Compaction encapsulates information about a compaction.
class Compaction {
public:
~Compaction();
// Return the level that is being compacted. Inputs from "level"
// and "level+1" will be merged to produce a set of "level+1" files.
int level() const { return level_; }
// Return the object that holds the edits to the descriptor done
// by this compaction.
VersionEdit* edit() { return &edit_; }
// "which" must be either 0 or 1
int num_input_files(int which) const { return inputs_[which].size(); }
// Return the ith input file at "level()+which" ("which" must be 0 or 1).
FileMetaData* input(int which, int i) const { return inputs_[which][i]; }
// Maximum size of files to build during this compaction.
uint64_t MaxOutputFileSize() const { return max_output_file_size_; }
// Is this a trivial compaction that can be implemented by just
// moving a single input file to the next level (no merging or splitting)
bool IsTrivialMove() const;
// Add all inputs to this compaction as delete operations to *edit.
void AddInputDeletions(VersionEdit* edit);
// Returns true if the information we have available guarantees that
// the compaction is producing data in "level+1" for which no data exists
// in levels greater than "level+1".
bool IsBaseLevelForKey(const Slice& user_key);
// Returns true iff we should stop building the current output
// before processing "internal_key".
bool ShouldStopBefore(const Slice& internal_key);
// Release the input version for the compaction, once the compaction
// is successful.
void ReleaseInputs();
private:
friend class Version;
friend class VersionSet;
explicit Compaction(int level);
int level_;
uint64_t max_output_file_size_;
Version* input_version_;
VersionEdit edit_;
// Each compaction reads inputs from "level_" and "level_+1"
std::vector<FileMetaData*> inputs_[2]; // The two sets of inputs
// State used to check for number of of overlapping grandparent files
// (parent == level_ + 1, grandparent == level_ + 2)
std::vector<FileMetaData*> grandparents_;
size_t grandparent_index_; // Index in grandparent_starts_
bool seen_key_; // Some output key has been seen
int64_t overlapped_bytes_; // Bytes of overlap between current output
// and grandparent files
// State for implementing IsBaseLevelForKey
// level_ptrs_ holds indices into input_version_->levels_: our state
// is that we are positioned at one of the file ranges for each
// higher level than the ones involved in this compaction (i.e. for
// all L >= level_ + 2).
size_t level_ptrs_[config::kNumLevels];
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_VERSION_SET_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/version_set.h"
#include "util/logging.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace leveldb {
class FindFileTest {
public:
std::vector<FileMetaData*> files_;
bool disjoint_sorted_files_;
FindFileTest() : disjoint_sorted_files_(true) { }
~FindFileTest() {
for (int i = 0; i < files_.size(); i++) {
delete files_[i];
}
}
void Add(const char* smallest, const char* largest,
SequenceNumber smallest_seq = 100,
SequenceNumber largest_seq = 100) {
FileMetaData* f = new FileMetaData;
f->number = files_.size() + 1;
f->smallest = InternalKey(smallest, smallest_seq, kTypeValue);
f->largest = InternalKey(largest, largest_seq, kTypeValue);
files_.push_back(f);
}
int Find(const char* key) {
InternalKey target(key, 100, kTypeValue);
InternalKeyComparator cmp(BytewiseComparator());
return FindFile(cmp, files_, target.Encode());
}
bool Overlaps(const char* smallest, const char* largest) {
InternalKeyComparator cmp(BytewiseComparator());
Slice s(smallest != NULL ? smallest : "");
Slice l(largest != NULL ? largest : "");
return SomeFileOverlapsRange(cmp, disjoint_sorted_files_, files_,
(smallest != NULL ? &s : NULL),
(largest != NULL ? &l : NULL));
}
};
TEST(FindFileTest, Empty) {
ASSERT_EQ(0, Find("foo"));
ASSERT_TRUE(! Overlaps("a", "z"));
ASSERT_TRUE(! Overlaps(NULL, "z"));
ASSERT_TRUE(! Overlaps("a", NULL));
ASSERT_TRUE(! Overlaps(NULL, NULL));
}
TEST(FindFileTest, Single) {
Add("p", "q");
ASSERT_EQ(0, Find("a"));
ASSERT_EQ(0, Find("p"));
ASSERT_EQ(0, Find("p1"));
ASSERT_EQ(0, Find("q"));
ASSERT_EQ(1, Find("q1"));
ASSERT_EQ(1, Find("z"));
ASSERT_TRUE(! Overlaps("a", "b"));
ASSERT_TRUE(! Overlaps("z1", "z2"));
ASSERT_TRUE(Overlaps("a", "p"));
ASSERT_TRUE(Overlaps("a", "q"));
ASSERT_TRUE(Overlaps("a", "z"));
ASSERT_TRUE(Overlaps("p", "p1"));
ASSERT_TRUE(Overlaps("p", "q"));
ASSERT_TRUE(Overlaps("p", "z"));
ASSERT_TRUE(Overlaps("p1", "p2"));
ASSERT_TRUE(Overlaps("p1", "z"));
ASSERT_TRUE(Overlaps("q", "q"));
ASSERT_TRUE(Overlaps("q", "q1"));
ASSERT_TRUE(! Overlaps(NULL, "j"));
ASSERT_TRUE(! Overlaps("r", NULL));
ASSERT_TRUE(Overlaps(NULL, "p"));
ASSERT_TRUE(Overlaps(NULL, "p1"));
ASSERT_TRUE(Overlaps("q", NULL));
ASSERT_TRUE(Overlaps(NULL, NULL));
}
TEST(FindFileTest, Multiple) {
Add("150", "200");
Add("200", "250");
Add("300", "350");
Add("400", "450");
ASSERT_EQ(0, Find("100"));
ASSERT_EQ(0, Find("150"));
ASSERT_EQ(0, Find("151"));
ASSERT_EQ(0, Find("199"));
ASSERT_EQ(0, Find("200"));
ASSERT_EQ(1, Find("201"));
ASSERT_EQ(1, Find("249"));
ASSERT_EQ(1, Find("250"));
ASSERT_EQ(2, Find("251"));
ASSERT_EQ(2, Find("299"));
ASSERT_EQ(2, Find("300"));
ASSERT_EQ(2, Find("349"));
ASSERT_EQ(2, Find("350"));
ASSERT_EQ(3, Find("351"));
ASSERT_EQ(3, Find("400"));
ASSERT_EQ(3, Find("450"));
ASSERT_EQ(4, Find("451"));
ASSERT_TRUE(! Overlaps("100", "149"));
ASSERT_TRUE(! Overlaps("251", "299"));
ASSERT_TRUE(! Overlaps("451", "500"));
ASSERT_TRUE(! Overlaps("351", "399"));
ASSERT_TRUE(Overlaps("100", "150"));
ASSERT_TRUE(Overlaps("100", "200"));
ASSERT_TRUE(Overlaps("100", "300"));
ASSERT_TRUE(Overlaps("100", "400"));
ASSERT_TRUE(Overlaps("100", "500"));
ASSERT_TRUE(Overlaps("375", "400"));
ASSERT_TRUE(Overlaps("450", "450"));
ASSERT_TRUE(Overlaps("450", "500"));
}
TEST(FindFileTest, MultipleNullBoundaries) {
Add("150", "200");
Add("200", "250");
Add("300", "350");
Add("400", "450");
ASSERT_TRUE(! Overlaps(NULL, "149"));
ASSERT_TRUE(! Overlaps("451", NULL));
ASSERT_TRUE(Overlaps(NULL, NULL));
ASSERT_TRUE(Overlaps(NULL, "150"));
ASSERT_TRUE(Overlaps(NULL, "199"));
ASSERT_TRUE(Overlaps(NULL, "200"));
ASSERT_TRUE(Overlaps(NULL, "201"));
ASSERT_TRUE(Overlaps(NULL, "400"));
ASSERT_TRUE(Overlaps(NULL, "800"));
ASSERT_TRUE(Overlaps("100", NULL));
ASSERT_TRUE(Overlaps("200", NULL));
ASSERT_TRUE(Overlaps("449", NULL));
ASSERT_TRUE(Overlaps("450", NULL));
}
TEST(FindFileTest, OverlapSequenceChecks) {
Add("200", "200", 5000, 3000);
ASSERT_TRUE(! Overlaps("199", "199"));
ASSERT_TRUE(! Overlaps("201", "300"));
ASSERT_TRUE(Overlaps("200", "200"));
ASSERT_TRUE(Overlaps("190", "200"));
ASSERT_TRUE(Overlaps("200", "210"));
}
TEST(FindFileTest, OverlappingFiles) {
Add("150", "600");
Add("400", "500");
disjoint_sorted_files_ = false;
ASSERT_TRUE(! Overlaps("100", "149"));
ASSERT_TRUE(! Overlaps("601", "700"));
ASSERT_TRUE(Overlaps("100", "150"));
ASSERT_TRUE(Overlaps("100", "200"));
ASSERT_TRUE(Overlaps("100", "300"));
ASSERT_TRUE(Overlaps("100", "400"));
ASSERT_TRUE(Overlaps("100", "500"));
ASSERT_TRUE(Overlaps("375", "400"));
ASSERT_TRUE(Overlaps("450", "450"));
ASSERT_TRUE(Overlaps("450", "500"));
ASSERT_TRUE(Overlaps("450", "700"));
ASSERT_TRUE(Overlaps("600", "700"));
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// WriteBatch::rep_ :=
// sequence: fixed64
// count: fixed32
// data: record[count]
// record :=
// kTypeValue varstring varstring |
// kTypeDeletion varstring
// varstring :=
// len: varint32
// data: uint8[len]
#include "leveldb/write_batch.h"
#include "leveldb/db.h"
#include "db/dbformat.h"
#include "db/memtable.h"
#include "db/write_batch_internal.h"
#include "util/coding.h"
namespace leveldb {
// WriteBatch header has an 8-byte sequence number followed by a 4-byte count.
static const size_t kHeader = 12;
WriteBatch::WriteBatch() {
Clear();
}
WriteBatch::~WriteBatch() { }
WriteBatch::Handler::~Handler() { }
void WriteBatch::Clear() {
rep_.clear();
rep_.resize(kHeader);
}
Status WriteBatch::Iterate(Handler* handler) const {
Slice input(rep_);
if (input.size() < kHeader) {
return Status::Corruption("malformed WriteBatch (too small)");
}
input.remove_prefix(kHeader);
Slice key, value;
int found = 0;
while (!input.empty()) {
found++;
char tag = input[0];
input.remove_prefix(1);
switch (tag) {
case kTypeValue:
if (GetLengthPrefixedSlice(&input, &key) &&
GetLengthPrefixedSlice(&input, &value)) {
handler->Put(key, value);
} else {
return Status::Corruption("bad WriteBatch Put");
}
break;
case kTypeDeletion:
if (GetLengthPrefixedSlice(&input, &key)) {
handler->Delete(key);
} else {
return Status::Corruption("bad WriteBatch Delete");
}
break;
default:
return Status::Corruption("unknown WriteBatch tag");
}
}
if (found != WriteBatchInternal::Count(this)) {
return Status::Corruption("WriteBatch has wrong count");
} else {
return Status::OK();
}
}
int WriteBatchInternal::Count(const WriteBatch* b) {
return DecodeFixed32(b->rep_.data() + 8);
}
void WriteBatchInternal::SetCount(WriteBatch* b, int n) {
EncodeFixed32(&b->rep_[8], n);
}
SequenceNumber WriteBatchInternal::Sequence(const WriteBatch* b) {
return SequenceNumber(DecodeFixed64(b->rep_.data()));
}
void WriteBatchInternal::SetSequence(WriteBatch* b, SequenceNumber seq) {
EncodeFixed64(&b->rep_[0], seq);
}
void WriteBatch::Put(const Slice& key, const Slice& value) {
WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
rep_.push_back(static_cast<char>(kTypeValue));
PutLengthPrefixedSlice(&rep_, key);
PutLengthPrefixedSlice(&rep_, value);
}
void WriteBatch::Delete(const Slice& key) {
WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
rep_.push_back(static_cast<char>(kTypeDeletion));
PutLengthPrefixedSlice(&rep_, key);
}
namespace {
class MemTableInserter : public WriteBatch::Handler {
public:
SequenceNumber sequence_;
MemTable* mem_;
virtual void Put(const Slice& key, const Slice& value) {
mem_->Add(sequence_, kTypeValue, key, value);
sequence_++;
}
virtual void Delete(const Slice& key) {
mem_->Add(sequence_, kTypeDeletion, key, Slice());
sequence_++;
}
};
} // namespace
Status WriteBatchInternal::InsertInto(const WriteBatch* b,
MemTable* memtable) {
MemTableInserter inserter;
inserter.sequence_ = WriteBatchInternal::Sequence(b);
inserter.mem_ = memtable;
return b->Iterate(&inserter);
}
void WriteBatchInternal::SetContents(WriteBatch* b, const Slice& contents) {
assert(contents.size() >= kHeader);
b->rep_.assign(contents.data(), contents.size());
}
void WriteBatchInternal::Append(WriteBatch* dst, const WriteBatch* src) {
SetCount(dst, Count(dst) + Count(src));
assert(src->rep_.size() >= kHeader);
dst->rep_.append(src->rep_.data() + kHeader, src->rep_.size() - kHeader);
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_
#define STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_
#include "leveldb/write_batch.h"
namespace leveldb {
class MemTable;
// WriteBatchInternal provides static methods for manipulating a
// WriteBatch that we don't want in the public WriteBatch interface.
class WriteBatchInternal {
public:
// Return the number of entries in the batch.
static int Count(const WriteBatch* batch);
// Set the count for the number of entries in the batch.
static void SetCount(WriteBatch* batch, int n);
// Return the seqeunce number for the start of this batch.
static SequenceNumber Sequence(const WriteBatch* batch);
// Store the specified number as the seqeunce number for the start of
// this batch.
static void SetSequence(WriteBatch* batch, SequenceNumber seq);
static Slice Contents(const WriteBatch* batch) {
return Slice(batch->rep_);
}
static size_t ByteSize(const WriteBatch* batch) {
return batch->rep_.size();
}
static void SetContents(WriteBatch* batch, const Slice& contents);
static Status InsertInto(const WriteBatch* batch, MemTable* memtable);
static void Append(WriteBatch* dst, const WriteBatch* src);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "leveldb/db.h"
#include "db/memtable.h"
#include "db/write_batch_internal.h"
#include "leveldb/env.h"
#include "util/logging.h"
#include "util/testharness.h"
namespace leveldb {
static std::string PrintContents(WriteBatch* b) {
InternalKeyComparator cmp(BytewiseComparator());
MemTable* mem = new MemTable(cmp);
mem->Ref();
std::string state;
Status s = WriteBatchInternal::InsertInto(b, mem);
int count = 0;
Iterator* iter = mem->NewIterator();
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
ParsedInternalKey ikey;
ASSERT_TRUE(ParseInternalKey(iter->key(), &ikey));
switch (ikey.type) {
case kTypeValue:
state.append("Put(");
state.append(ikey.user_key.ToString());
state.append(", ");
state.append(iter->value().ToString());
state.append(")");
count++;
break;
case kTypeDeletion:
state.append("Delete(");
state.append(ikey.user_key.ToString());
state.append(")");
count++;
break;
}
state.append("@");
state.append(NumberToString(ikey.sequence));
}
delete iter;
if (!s.ok()) {
state.append("ParseError()");
} else if (count != WriteBatchInternal::Count(b)) {
state.append("CountMismatch()");
}
mem->Unref();
return state;
}
class WriteBatchTest { };
TEST(WriteBatchTest, Empty) {
WriteBatch batch;
ASSERT_EQ("", PrintContents(&batch));
ASSERT_EQ(0, WriteBatchInternal::Count(&batch));
}
TEST(WriteBatchTest, Multiple) {
WriteBatch batch;
batch.Put(Slice("foo"), Slice("bar"));
batch.Delete(Slice("box"));
batch.Put(Slice("baz"), Slice("boo"));
WriteBatchInternal::SetSequence(&batch, 100);
ASSERT_EQ(100, WriteBatchInternal::Sequence(&batch));
ASSERT_EQ(3, WriteBatchInternal::Count(&batch));
ASSERT_EQ("Put(baz, boo)@102"
"Delete(box)@101"
"Put(foo, bar)@100",
PrintContents(&batch));
}
TEST(WriteBatchTest, Corruption) {
WriteBatch batch;
batch.Put(Slice("foo"), Slice("bar"));
batch.Delete(Slice("box"));
WriteBatchInternal::SetSequence(&batch, 200);
Slice contents = WriteBatchInternal::Contents(&batch);
WriteBatchInternal::SetContents(&batch,
Slice(contents.data(),contents.size()-1));
ASSERT_EQ("Put(foo, bar)@200"
"ParseError()",
PrintContents(&batch));
}
TEST(WriteBatchTest, Append) {
WriteBatch b1, b2;
WriteBatchInternal::SetSequence(&b1, 200);
WriteBatchInternal::SetSequence(&b2, 300);
WriteBatchInternal::Append(&b1, &b2);
ASSERT_EQ("",
PrintContents(&b1));
b2.Put("a", "va");
WriteBatchInternal::Append(&b1, &b2);
ASSERT_EQ("Put(a, va)@200",
PrintContents(&b1));
b2.Clear();
b2.Put("b", "vb");
WriteBatchInternal::Append(&b1, &b2);
ASSERT_EQ("Put(a, va)@200"
"Put(b, vb)@201",
PrintContents(&b1));
b2.Delete("foo");
WriteBatchInternal::Append(&b1, &b2);
ASSERT_EQ("Put(a, va)@200"
"Put(b, vb)@202"
"Put(b, vb)@201"
"Delete(foo)@203",
PrintContents(&b1));
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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src/leveldb/doc/bench/db_bench_sqlite3.cc
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include <stdio.h>
#include <stdlib.h>
#include <sqlite3.h>
#include "util/histogram.h"
#include "util/random.h"
#include "util/testutil.h"
// Comma-separated list of operations to run in the specified order
// Actual benchmarks:
//
// fillseq -- write N values in sequential key order in async mode
// fillseqsync -- write N/100 values in sequential key order in sync mode
// fillseqbatch -- batch write N values in sequential key order in async mode
// fillrandom -- write N values in random key order in async mode
// fillrandsync -- write N/100 values in random key order in sync mode
// fillrandbatch -- batch write N values in sequential key order in async mode
// overwrite -- overwrite N values in random key order in async mode
// fillrand100K -- write N/1000 100K values in random order in async mode
// fillseq100K -- write N/1000 100K values in sequential order in async mode
// readseq -- read N times sequentially
// readrandom -- read N times in random order
// readrand100K -- read N/1000 100K values in sequential order in async mode
static const char* FLAGS_benchmarks =
"fillseq,"
"fillseqsync,"
"fillseqbatch,"
"fillrandom,"
"fillrandsync,"
"fillrandbatch,"
"overwrite,"
"overwritebatch,"
"readrandom,"
"readseq,"
"fillrand100K,"
"fillseq100K,"
"readseq,"
"readrand100K,"
;
// Number of key/values to place in database
static int FLAGS_num = 1000000;
// Number of read operations to do. If negative, do FLAGS_num reads.
static int FLAGS_reads = -1;
// Size of each value
static int FLAGS_value_size = 100;
// Print histogram of operation timings
static bool FLAGS_histogram = false;
// Arrange to generate values that shrink to this fraction of
// their original size after compression
static double FLAGS_compression_ratio = 0.5;
// Page size. Default 1 KB.
static int FLAGS_page_size = 1024;
// Number of pages.
// Default cache size = FLAGS_page_size * FLAGS_num_pages = 4 MB.
static int FLAGS_num_pages = 4096;
// If true, do not destroy the existing database. If you set this
// flag and also specify a benchmark that wants a fresh database, that
// benchmark will fail.
static bool FLAGS_use_existing_db = false;
// If true, we allow batch writes to occur
static bool FLAGS_transaction = true;
// If true, we enable Write-Ahead Logging
static bool FLAGS_WAL_enabled = true;
// Use the db with the following name.
static const char* FLAGS_db = NULL;
inline
static void ExecErrorCheck(int status, char *err_msg) {
if (status != SQLITE_OK) {
fprintf(stderr, "SQL error: %s\n", err_msg);
sqlite3_free(err_msg);
exit(1);
}
}
inline
static void StepErrorCheck(int status) {
if (status != SQLITE_DONE) {
fprintf(stderr, "SQL step error: status = %d\n", status);
exit(1);
}
}
inline
static void ErrorCheck(int status) {
if (status != SQLITE_OK) {
fprintf(stderr, "sqlite3 error: status = %d\n", status);
exit(1);
}
}
inline
static void WalCheckpoint(sqlite3* db_) {
// Flush all writes to disk
if (FLAGS_WAL_enabled) {
sqlite3_wal_checkpoint_v2(db_, NULL, SQLITE_CHECKPOINT_FULL, NULL, NULL);
}
}
namespace leveldb {
// Helper for quickly generating random data.
namespace {
class RandomGenerator {
private:
std::string data_;
int pos_;
public:
RandomGenerator() {
// We use a limited amount of data over and over again and ensure
// that it is larger than the compression window (32KB), and also
// large enough to serve all typical value sizes we want to write.
Random rnd(301);
std::string piece;
while (data_.size() < 1048576) {
// Add a short fragment that is as compressible as specified
// by FLAGS_compression_ratio.
test::CompressibleString(&rnd, FLAGS_compression_ratio, 100, &piece);
data_.append(piece);
}
pos_ = 0;
}
Slice Generate(int len) {
if (pos_ + len > data_.size()) {
pos_ = 0;
assert(len < data_.size());
}
pos_ += len;
return Slice(data_.data() + pos_ - len, len);
}
};
static Slice TrimSpace(Slice s) {
int start = 0;
while (start < s.size() && isspace(s[start])) {
start++;
}
int limit = s.size();
while (limit > start && isspace(s[limit-1])) {
limit--;
}
return Slice(s.data() + start, limit - start);
}
} // namespace
class Benchmark {
private:
sqlite3* db_;
int db_num_;
int num_;
int reads_;
double start_;
double last_op_finish_;
int64_t bytes_;
std::string message_;
Histogram hist_;
RandomGenerator gen_;
Random rand_;
// State kept for progress messages
int done_;
int next_report_; // When to report next
void PrintHeader() {
const int kKeySize = 16;
PrintEnvironment();
fprintf(stdout, "Keys: %d bytes each\n", kKeySize);
fprintf(stdout, "Values: %d bytes each\n", FLAGS_value_size);
fprintf(stdout, "Entries: %d\n", num_);
fprintf(stdout, "RawSize: %.1f MB (estimated)\n",
((static_cast<int64_t>(kKeySize + FLAGS_value_size) * num_)
/ 1048576.0));
PrintWarnings();
fprintf(stdout, "------------------------------------------------\n");
}
void PrintWarnings() {
#if defined(__GNUC__) && !defined(__OPTIMIZE__)
fprintf(stdout,
"WARNING: Optimization is disabled: benchmarks unnecessarily slow\n"
);
#endif
#ifndef NDEBUG
fprintf(stdout,
"WARNING: Assertions are enabled; benchmarks unnecessarily slow\n");
#endif
}
void PrintEnvironment() {
fprintf(stderr, "SQLite: version %s\n", SQLITE_VERSION);
#if defined(__linux)
time_t now = time(NULL);
fprintf(stderr, "Date: %s", ctime(&now)); // ctime() adds newline
FILE* cpuinfo = fopen("/proc/cpuinfo", "r");
if (cpuinfo != NULL) {
char line[1000];
int num_cpus = 0;
std::string cpu_type;
std::string cache_size;
while (fgets(line, sizeof(line), cpuinfo) != NULL) {
const char* sep = strchr(line, ':');
if (sep == NULL) {
continue;
}
Slice key = TrimSpace(Slice(line, sep - 1 - line));
Slice val = TrimSpace(Slice(sep + 1));
if (key == "model name") {
++num_cpus;
cpu_type = val.ToString();
} else if (key == "cache size") {
cache_size = val.ToString();
}
}
fclose(cpuinfo);
fprintf(stderr, "CPU: %d * %s\n", num_cpus, cpu_type.c_str());
fprintf(stderr, "CPUCache: %s\n", cache_size.c_str());
}
#endif
}
void Start() {
start_ = Env::Default()->NowMicros() * 1e-6;
bytes_ = 0;
message_.clear();
last_op_finish_ = start_;
hist_.Clear();
done_ = 0;
next_report_ = 100;
}
void FinishedSingleOp() {
if (FLAGS_histogram) {
double now = Env::Default()->NowMicros() * 1e-6;
double micros = (now - last_op_finish_) * 1e6;
hist_.Add(micros);
if (micros > 20000) {
fprintf(stderr, "long op: %.1f micros%30s\r", micros, "");
fflush(stderr);
}
last_op_finish_ = now;
}
done_++;
if (done_ >= next_report_) {
if (next_report_ < 1000) next_report_ += 100;
else if (next_report_ < 5000) next_report_ += 500;
else if (next_report_ < 10000) next_report_ += 1000;
else if (next_report_ < 50000) next_report_ += 5000;
else if (next_report_ < 100000) next_report_ += 10000;
else if (next_report_ < 500000) next_report_ += 50000;
else next_report_ += 100000;
fprintf(stderr, "... finished %d ops%30s\r", done_, "");
fflush(stderr);
}
}
void Stop(const Slice& name) {
double finish = Env::Default()->NowMicros() * 1e-6;
// Pretend at least one op was done in case we are running a benchmark
// that does not call FinishedSingleOp().
if (done_ < 1) done_ = 1;
if (bytes_ > 0) {
char rate[100];
snprintf(rate, sizeof(rate), "%6.1f MB/s",
(bytes_ / 1048576.0) / (finish - start_));
if (!message_.empty()) {
message_ = std::string(rate) + " " + message_;
} else {
message_ = rate;
}
}
fprintf(stdout, "%-12s : %11.3f micros/op;%s%s\n",
name.ToString().c_str(),
(finish - start_) * 1e6 / done_,
(message_.empty() ? "" : " "),
message_.c_str());
if (FLAGS_histogram) {
fprintf(stdout, "Microseconds per op:\n%s\n", hist_.ToString().c_str());
}
fflush(stdout);
}
public:
enum Order {
SEQUENTIAL,
RANDOM
};
enum DBState {
FRESH,
EXISTING
};
Benchmark()
: db_(NULL),
db_num_(0),
num_(FLAGS_num),
reads_(FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads),
bytes_(0),
rand_(301) {
std::vector<std::string> files;
std::string test_dir;
Env::Default()->GetTestDirectory(&test_dir);
Env::Default()->GetChildren(test_dir, &files);
if (!FLAGS_use_existing_db) {
for (int i = 0; i < files.size(); i++) {
if (Slice(files[i]).starts_with("dbbench_sqlite3")) {
std::string file_name(test_dir);
file_name += "/";
file_name += files[i];
Env::Default()->DeleteFile(file_name.c_str());
}
}
}
}
~Benchmark() {
int status = sqlite3_close(db_);
ErrorCheck(status);
}
void Run() {
PrintHeader();
Open();
const char* benchmarks = FLAGS_benchmarks;
while (benchmarks != NULL) {
const char* sep = strchr(benchmarks, ',');
Slice name;
if (sep == NULL) {
name = benchmarks;
benchmarks = NULL;
} else {
name = Slice(benchmarks, sep - benchmarks);
benchmarks = sep + 1;
}
bytes_ = 0;
Start();
bool known = true;
bool write_sync = false;
if (name == Slice("fillseq")) {
Write(write_sync, SEQUENTIAL, FRESH, num_, FLAGS_value_size, 1);
WalCheckpoint(db_);
} else if (name == Slice("fillseqbatch")) {
Write(write_sync, SEQUENTIAL, FRESH, num_, FLAGS_value_size, 1000);
WalCheckpoint(db_);
} else if (name == Slice("fillrandom")) {
Write(write_sync, RANDOM, FRESH, num_, FLAGS_value_size, 1);
WalCheckpoint(db_);
} else if (name == Slice("fillrandbatch")) {
Write(write_sync, RANDOM, FRESH, num_, FLAGS_value_size, 1000);
WalCheckpoint(db_);
} else if (name == Slice("overwrite")) {
Write(write_sync, RANDOM, EXISTING, num_, FLAGS_value_size, 1);
WalCheckpoint(db_);
} else if (name == Slice("overwritebatch")) {
Write(write_sync, RANDOM, EXISTING, num_, FLAGS_value_size, 1000);
WalCheckpoint(db_);
} else if (name == Slice("fillrandsync")) {
write_sync = true;
Write(write_sync, RANDOM, FRESH, num_ / 100, FLAGS_value_size, 1);
WalCheckpoint(db_);
} else if (name == Slice("fillseqsync")) {
write_sync = true;
Write(write_sync, SEQUENTIAL, FRESH, num_ / 100, FLAGS_value_size, 1);
WalCheckpoint(db_);
} else if (name == Slice("fillrand100K")) {
Write(write_sync, RANDOM, FRESH, num_ / 1000, 100 * 1000, 1);
WalCheckpoint(db_);
} else if (name == Slice("fillseq100K")) {
Write(write_sync, SEQUENTIAL, FRESH, num_ / 1000, 100 * 1000, 1);
WalCheckpoint(db_);
} else if (name == Slice("readseq")) {
ReadSequential();
} else if (name == Slice("readrandom")) {
Read(RANDOM, 1);
} else if (name == Slice("readrand100K")) {
int n = reads_;
reads_ /= 1000;
Read(RANDOM, 1);
reads_ = n;
} else {
known = false;
if (name != Slice()) { // No error message for empty name
fprintf(stderr, "unknown benchmark '%s'\n", name.ToString().c_str());
}
}
if (known) {
Stop(name);
}
}
}
void Open() {
assert(db_ == NULL);
int status;
char file_name[100];
char* err_msg = NULL;
db_num_++;
// Open database
std::string tmp_dir;
Env::Default()->GetTestDirectory(&tmp_dir);
snprintf(file_name, sizeof(file_name),
"%s/dbbench_sqlite3-%d.db",
tmp_dir.c_str(),
db_num_);
status = sqlite3_open(file_name, &db_);
if (status) {
fprintf(stderr, "open error: %s\n", sqlite3_errmsg(db_));
exit(1);
}
// Change SQLite cache size
char cache_size[100];
snprintf(cache_size, sizeof(cache_size), "PRAGMA cache_size = %d",
FLAGS_num_pages);
status = sqlite3_exec(db_, cache_size, NULL, NULL, &err_msg);
ExecErrorCheck(status, err_msg);
// FLAGS_page_size is defaulted to 1024
if (FLAGS_page_size != 1024) {
char page_size[100];
snprintf(page_size, sizeof(page_size), "PRAGMA page_size = %d",
FLAGS_page_size);
status = sqlite3_exec(db_, page_size, NULL, NULL, &err_msg);
ExecErrorCheck(status, err_msg);
}
// Change journal mode to WAL if WAL enabled flag is on
if (FLAGS_WAL_enabled) {
std::string WAL_stmt = "PRAGMA journal_mode = WAL";
// LevelDB's default cache size is a combined 4 MB
std::string WAL_checkpoint = "PRAGMA wal_autocheckpoint = 4096";
status = sqlite3_exec(db_, WAL_stmt.c_str(), NULL, NULL, &err_msg);
ExecErrorCheck(status, err_msg);
status = sqlite3_exec(db_, WAL_checkpoint.c_str(), NULL, NULL, &err_msg);
ExecErrorCheck(status, err_msg);
}
// Change locking mode to exclusive and create tables/index for database
std::string locking_stmt = "PRAGMA locking_mode = EXCLUSIVE";
std::string create_stmt =
"CREATE TABLE test (key blob, value blob, PRIMARY KEY(key))";
std::string stmt_array[] = { locking_stmt, create_stmt };
int stmt_array_length = sizeof(stmt_array) / sizeof(std::string);
for (int i = 0; i < stmt_array_length; i++) {
status = sqlite3_exec(db_, stmt_array[i].c_str(), NULL, NULL, &err_msg);
ExecErrorCheck(status, err_msg);
}
}
void Write(bool write_sync, Order order, DBState state,
int num_entries, int value_size, int entries_per_batch) {
// Create new database if state == FRESH
if (state == FRESH) {
if (FLAGS_use_existing_db) {
message_ = "skipping (--use_existing_db is true)";
return;
}
sqlite3_close(db_);
db_ = NULL;
Open();
Start();
}
if (num_entries != num_) {
char msg[100];
snprintf(msg, sizeof(msg), "(%d ops)", num_entries);
message_ = msg;
}
char* err_msg = NULL;
int status;
sqlite3_stmt *replace_stmt, *begin_trans_stmt, *end_trans_stmt;
std::string replace_str = "REPLACE INTO test (key, value) VALUES (?, ?)";
std::string begin_trans_str = "BEGIN TRANSACTION;";
std::string end_trans_str = "END TRANSACTION;";
// Check for synchronous flag in options
std::string sync_stmt = (write_sync) ? "PRAGMA synchronous = FULL" :
"PRAGMA synchronous = OFF";
status = sqlite3_exec(db_, sync_stmt.c_str(), NULL, NULL, &err_msg);
ExecErrorCheck(status, err_msg);
// Preparing sqlite3 statements
status = sqlite3_prepare_v2(db_, replace_str.c_str(), -1,
&replace_stmt, NULL);
ErrorCheck(status);
status = sqlite3_prepare_v2(db_, begin_trans_str.c_str(), -1,
&begin_trans_stmt, NULL);
ErrorCheck(status);
status = sqlite3_prepare_v2(db_, end_trans_str.c_str(), -1,
&end_trans_stmt, NULL);
ErrorCheck(status);
bool transaction = (entries_per_batch > 1);
for (int i = 0; i < num_entries; i += entries_per_batch) {
// Begin write transaction
if (FLAGS_transaction && transaction) {
status = sqlite3_step(begin_trans_stmt);
StepErrorCheck(status);
status = sqlite3_reset(begin_trans_stmt);
ErrorCheck(status);
}
// Create and execute SQL statements
for (int j = 0; j < entries_per_batch; j++) {
const char* value = gen_.Generate(value_size).data();
// Create values for key-value pair
const int k = (order == SEQUENTIAL) ? i + j :
(rand_.Next() % num_entries);
char key[100];
snprintf(key, sizeof(key), "%016d", k);
// Bind KV values into replace_stmt
status = sqlite3_bind_blob(replace_stmt, 1, key, 16, SQLITE_STATIC);
ErrorCheck(status);
status = sqlite3_bind_blob(replace_stmt, 2, value,
value_size, SQLITE_STATIC);
ErrorCheck(status);
// Execute replace_stmt
bytes_ += value_size + strlen(key);
status = sqlite3_step(replace_stmt);
StepErrorCheck(status);
// Reset SQLite statement for another use
status = sqlite3_clear_bindings(replace_stmt);
ErrorCheck(status);
status = sqlite3_reset(replace_stmt);
ErrorCheck(status);
FinishedSingleOp();
}
// End write transaction
if (FLAGS_transaction && transaction) {
status = sqlite3_step(end_trans_stmt);
StepErrorCheck(status);
status = sqlite3_reset(end_trans_stmt);
ErrorCheck(status);
}
}
status = sqlite3_finalize(replace_stmt);
ErrorCheck(status);
status = sqlite3_finalize(begin_trans_stmt);
ErrorCheck(status);
status = sqlite3_finalize(end_trans_stmt);
ErrorCheck(status);
}
void Read(Order order, int entries_per_batch) {
int status;
sqlite3_stmt *read_stmt, *begin_trans_stmt, *end_trans_stmt;
std::string read_str = "SELECT * FROM test WHERE key = ?";
std::string begin_trans_str = "BEGIN TRANSACTION;";
std::string end_trans_str = "END TRANSACTION;";
// Preparing sqlite3 statements
status = sqlite3_prepare_v2(db_, begin_trans_str.c_str(), -1,
&begin_trans_stmt, NULL);
ErrorCheck(status);
status = sqlite3_prepare_v2(db_, end_trans_str.c_str(), -1,
&end_trans_stmt, NULL);
ErrorCheck(status);
status = sqlite3_prepare_v2(db_, read_str.c_str(), -1, &read_stmt, NULL);
ErrorCheck(status);
bool transaction = (entries_per_batch > 1);
for (int i = 0; i < reads_; i += entries_per_batch) {
// Begin read transaction
if (FLAGS_transaction && transaction) {
status = sqlite3_step(begin_trans_stmt);
StepErrorCheck(status);
status = sqlite3_reset(begin_trans_stmt);
ErrorCheck(status);
}
// Create and execute SQL statements
for (int j = 0; j < entries_per_batch; j++) {
// Create key value
char key[100];
int k = (order == SEQUENTIAL) ? i + j : (rand_.Next() % reads_);
snprintf(key, sizeof(key), "%016d", k);
// Bind key value into read_stmt
status = sqlite3_bind_blob(read_stmt, 1, key, 16, SQLITE_STATIC);
ErrorCheck(status);
// Execute read statement
while ((status = sqlite3_step(read_stmt)) == SQLITE_ROW) {}
StepErrorCheck(status);
// Reset SQLite statement for another use
status = sqlite3_clear_bindings(read_stmt);
ErrorCheck(status);
status = sqlite3_reset(read_stmt);
ErrorCheck(status);
FinishedSingleOp();
}
// End read transaction
if (FLAGS_transaction && transaction) {
status = sqlite3_step(end_trans_stmt);
StepErrorCheck(status);
status = sqlite3_reset(end_trans_stmt);
ErrorCheck(status);
}
}
status = sqlite3_finalize(read_stmt);
ErrorCheck(status);
status = sqlite3_finalize(begin_trans_stmt);
ErrorCheck(status);
status = sqlite3_finalize(end_trans_stmt);
ErrorCheck(status);
}
void ReadSequential() {
int status;
sqlite3_stmt *pStmt;
std::string read_str = "SELECT * FROM test ORDER BY key";
status = sqlite3_prepare_v2(db_, read_str.c_str(), -1, &pStmt, NULL);
ErrorCheck(status);
for (int i = 0; i < reads_ && SQLITE_ROW == sqlite3_step(pStmt); i++) {
bytes_ += sqlite3_column_bytes(pStmt, 1) + sqlite3_column_bytes(pStmt, 2);
FinishedSingleOp();
}
status = sqlite3_finalize(pStmt);
ErrorCheck(status);
}
};
} // namespace leveldb
int main(int argc, char** argv) {
std::string default_db_path;
for (int i = 1; i < argc; i++) {
double d;
int n;
char junk;
if (leveldb::Slice(argv[i]).starts_with("--benchmarks=")) {
FLAGS_benchmarks = argv[i] + strlen("--benchmarks=");
} else if (sscanf(argv[i], "--histogram=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_histogram = n;
} else if (sscanf(argv[i], "--compression_ratio=%lf%c", &d, &junk) == 1) {
FLAGS_compression_ratio = d;
} else if (sscanf(argv[i], "--use_existing_db=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_use_existing_db = n;
} else if (sscanf(argv[i], "--num=%d%c", &n, &junk) == 1) {
FLAGS_num = n;
} else if (sscanf(argv[i], "--reads=%d%c", &n, &junk) == 1) {
FLAGS_reads = n;
} else if (sscanf(argv[i], "--value_size=%d%c", &n, &junk) == 1) {
FLAGS_value_size = n;
} else if (leveldb::Slice(argv[i]) == leveldb::Slice("--no_transaction")) {
FLAGS_transaction = false;
} else if (sscanf(argv[i], "--page_size=%d%c", &n, &junk) == 1) {
FLAGS_page_size = n;
} else if (sscanf(argv[i], "--num_pages=%d%c", &n, &junk) == 1) {
FLAGS_num_pages = n;
} else if (sscanf(argv[i], "--WAL_enabled=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_WAL_enabled = n;
} else if (strncmp(argv[i], "--db=", 5) == 0) {
FLAGS_db = argv[i] + 5;
} else {
fprintf(stderr, "Invalid flag '%s'\n", argv[i]);
exit(1);
}
}
// Choose a location for the test database if none given with --db=<path>
if (FLAGS_db == NULL) {
leveldb::Env::Default()->GetTestDirectory(&default_db_path);
default_db_path += "/dbbench";
FLAGS_db = default_db_path.c_str();
}
leveldb::Benchmark benchmark;
benchmark.Run();
return 0;
}

528
src/leveldb/doc/bench/db_bench_tree_db.cc
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@ -1,528 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include <stdio.h>
#include <stdlib.h>
#include <kcpolydb.h>
#include "util/histogram.h"
#include "util/random.h"
#include "util/testutil.h"
// Comma-separated list of operations to run in the specified order
// Actual benchmarks:
//
// fillseq -- write N values in sequential key order in async mode
// fillrandom -- write N values in random key order in async mode
// overwrite -- overwrite N values in random key order in async mode
// fillseqsync -- write N/100 values in sequential key order in sync mode
// fillrandsync -- write N/100 values in random key order in sync mode
// fillrand100K -- write N/1000 100K values in random order in async mode
// fillseq100K -- write N/1000 100K values in seq order in async mode
// readseq -- read N times sequentially
// readseq100K -- read N/1000 100K values in sequential order in async mode
// readrand100K -- read N/1000 100K values in sequential order in async mode
// readrandom -- read N times in random order
static const char* FLAGS_benchmarks =
"fillseq,"
"fillseqsync,"
"fillrandsync,"
"fillrandom,"
"overwrite,"
"readrandom,"
"readseq,"
"fillrand100K,"
"fillseq100K,"
"readseq100K,"
"readrand100K,"
;
// Number of key/values to place in database
static int FLAGS_num = 1000000;
// Number of read operations to do. If negative, do FLAGS_num reads.
static int FLAGS_reads = -1;
// Size of each value
static int FLAGS_value_size = 100;
// Arrange to generate values that shrink to this fraction of
// their original size after compression
static double FLAGS_compression_ratio = 0.5;
// Print histogram of operation timings
static bool FLAGS_histogram = false;
// Cache size. Default 4 MB
static int FLAGS_cache_size = 4194304;
// Page size. Default 1 KB
static int FLAGS_page_size = 1024;
// If true, do not destroy the existing database. If you set this
// flag and also specify a benchmark that wants a fresh database, that
// benchmark will fail.
static bool FLAGS_use_existing_db = false;
// Compression flag. If true, compression is on. If false, compression
// is off.
static bool FLAGS_compression = true;
// Use the db with the following name.
static const char* FLAGS_db = NULL;
inline
static void DBSynchronize(kyotocabinet::TreeDB* db_)
{
// Synchronize will flush writes to disk
if (!db_->synchronize()) {
fprintf(stderr, "synchronize error: %s\n", db_->error().name());
}
}
namespace leveldb {
// Helper for quickly generating random data.
namespace {
class RandomGenerator {
private:
std::string data_;
int pos_;
public:
RandomGenerator() {
// We use a limited amount of data over and over again and ensure
// that it is larger than the compression window (32KB), and also
// large enough to serve all typical value sizes we want to write.
Random rnd(301);
std::string piece;
while (data_.size() < 1048576) {
// Add a short fragment that is as compressible as specified
// by FLAGS_compression_ratio.
test::CompressibleString(&rnd, FLAGS_compression_ratio, 100, &piece);
data_.append(piece);
}
pos_ = 0;
}
Slice Generate(int len) {
if (pos_ + len > data_.size()) {
pos_ = 0;
assert(len < data_.size());
}
pos_ += len;
return Slice(data_.data() + pos_ - len, len);
}
};
static Slice TrimSpace(Slice s) {
int start = 0;
while (start < s.size() && isspace(s[start])) {
start++;
}
int limit = s.size();
while (limit > start && isspace(s[limit-1])) {
limit--;
}
return Slice(s.data() + start, limit - start);
}
} // namespace
class Benchmark {
private:
kyotocabinet::TreeDB* db_;
int db_num_;
int num_;
int reads_;
double start_;
double last_op_finish_;
int64_t bytes_;
std::string message_;
Histogram hist_;
RandomGenerator gen_;
Random rand_;
kyotocabinet::LZOCompressor<kyotocabinet::LZO::RAW> comp_;
// State kept for progress messages
int done_;
int next_report_; // When to report next
void PrintHeader() {
const int kKeySize = 16;
PrintEnvironment();
fprintf(stdout, "Keys: %d bytes each\n", kKeySize);
fprintf(stdout, "Values: %d bytes each (%d bytes after compression)\n",
FLAGS_value_size,
static_cast<int>(FLAGS_value_size * FLAGS_compression_ratio + 0.5));
fprintf(stdout, "Entries: %d\n", num_);
fprintf(stdout, "RawSize: %.1f MB (estimated)\n",
((static_cast<int64_t>(kKeySize + FLAGS_value_size) * num_)
/ 1048576.0));
fprintf(stdout, "FileSize: %.1f MB (estimated)\n",
(((kKeySize + FLAGS_value_size * FLAGS_compression_ratio) * num_)
/ 1048576.0));
PrintWarnings();
fprintf(stdout, "------------------------------------------------\n");
}
void PrintWarnings() {
#if defined(__GNUC__) && !defined(__OPTIMIZE__)
fprintf(stdout,
"WARNING: Optimization is disabled: benchmarks unnecessarily slow\n"
);
#endif
#ifndef NDEBUG
fprintf(stdout,
"WARNING: Assertions are enabled; benchmarks unnecessarily slow\n");
#endif
}
void PrintEnvironment() {
fprintf(stderr, "Kyoto Cabinet: version %s, lib ver %d, lib rev %d\n",
kyotocabinet::VERSION, kyotocabinet::LIBVER, kyotocabinet::LIBREV);
#if defined(__linux)
time_t now = time(NULL);
fprintf(stderr, "Date: %s", ctime(&now)); // ctime() adds newline
FILE* cpuinfo = fopen("/proc/cpuinfo", "r");
if (cpuinfo != NULL) {
char line[1000];
int num_cpus = 0;
std::string cpu_type;
std::string cache_size;
while (fgets(line, sizeof(line), cpuinfo) != NULL) {
const char* sep = strchr(line, ':');
if (sep == NULL) {
continue;
}
Slice key = TrimSpace(Slice(line, sep - 1 - line));
Slice val = TrimSpace(Slice(sep + 1));
if (key == "model name") {
++num_cpus;
cpu_type = val.ToString();
} else if (key == "cache size") {
cache_size = val.ToString();
}
}
fclose(cpuinfo);
fprintf(stderr, "CPU: %d * %s\n", num_cpus, cpu_type.c_str());
fprintf(stderr, "CPUCache: %s\n", cache_size.c_str());
}
#endif
}
void Start() {
start_ = Env::Default()->NowMicros() * 1e-6;
bytes_ = 0;
message_.clear();
last_op_finish_ = start_;
hist_.Clear();
done_ = 0;
next_report_ = 100;
}
void FinishedSingleOp() {
if (FLAGS_histogram) {
double now = Env::Default()->NowMicros() * 1e-6;
double micros = (now - last_op_finish_) * 1e6;
hist_.Add(micros);
if (micros > 20000) {
fprintf(stderr, "long op: %.1f micros%30s\r", micros, "");
fflush(stderr);
}
last_op_finish_ = now;
}
done_++;
if (done_ >= next_report_) {
if (next_report_ < 1000) next_report_ += 100;
else if (next_report_ < 5000) next_report_ += 500;
else if (next_report_ < 10000) next_report_ += 1000;
else if (next_report_ < 50000) next_report_ += 5000;
else if (next_report_ < 100000) next_report_ += 10000;
else if (next_report_ < 500000) next_report_ += 50000;
else next_report_ += 100000;
fprintf(stderr, "... finished %d ops%30s\r", done_, "");
fflush(stderr);
}
}
void Stop(const Slice& name) {
double finish = Env::Default()->NowMicros() * 1e-6;
// Pretend at least one op was done in case we are running a benchmark
// that does not call FinishedSingleOp().
if (done_ < 1) done_ = 1;
if (bytes_ > 0) {
char rate[100];
snprintf(rate, sizeof(rate), "%6.1f MB/s",
(bytes_ / 1048576.0) / (finish - start_));
if (!message_.empty()) {
message_ = std::string(rate) + " " + message_;
} else {
message_ = rate;
}
}
fprintf(stdout, "%-12s : %11.3f micros/op;%s%s\n",
name.ToString().c_str(),
(finish - start_) * 1e6 / done_,
(message_.empty() ? "" : " "),
message_.c_str());
if (FLAGS_histogram) {
fprintf(stdout, "Microseconds per op:\n%s\n", hist_.ToString().c_str());
}
fflush(stdout);
}
public:
enum Order {
SEQUENTIAL,
RANDOM
};
enum DBState {
FRESH,
EXISTING
};
Benchmark()
: db_(NULL),
num_(FLAGS_num),
reads_(FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads),
bytes_(0),
rand_(301) {
std::vector<std::string> files;
std::string test_dir;
Env::Default()->GetTestDirectory(&test_dir);
Env::Default()->GetChildren(test_dir.c_str(), &files);
if (!FLAGS_use_existing_db) {
for (int i = 0; i < files.size(); i++) {
if (Slice(files[i]).starts_with("dbbench_polyDB")) {
std::string file_name(test_dir);
file_name += "/";
file_name += files[i];
Env::Default()->DeleteFile(file_name.c_str());
}
}
}
}
~Benchmark() {
if (!db_->close()) {
fprintf(stderr, "close error: %s\n", db_->error().name());
}
}
void Run() {
PrintHeader();
Open(false);
const char* benchmarks = FLAGS_benchmarks;
while (benchmarks != NULL) {
const char* sep = strchr(benchmarks, ',');
Slice name;
if (sep == NULL) {
name = benchmarks;
benchmarks = NULL;
} else {
name = Slice(benchmarks, sep - benchmarks);
benchmarks = sep + 1;
}
Start();
bool known = true;
bool write_sync = false;
if (name == Slice("fillseq")) {
Write(write_sync, SEQUENTIAL, FRESH, num_, FLAGS_value_size, 1);
} else if (name == Slice("fillrandom")) {
Write(write_sync, RANDOM, FRESH, num_, FLAGS_value_size, 1);
DBSynchronize(db_);
} else if (name == Slice("overwrite")) {
Write(write_sync, RANDOM, EXISTING, num_, FLAGS_value_size, 1);
DBSynchronize(db_);
} else if (name == Slice("fillrandsync")) {
write_sync = true;
Write(write_sync, RANDOM, FRESH, num_ / 100, FLAGS_value_size, 1);
DBSynchronize(db_);
} else if (name == Slice("fillseqsync")) {
write_sync = true;
Write(write_sync, SEQUENTIAL, FRESH, num_ / 100, FLAGS_value_size, 1);
DBSynchronize(db_);
} else if (name == Slice("fillrand100K")) {
Write(write_sync, RANDOM, FRESH, num_ / 1000, 100 * 1000, 1);
DBSynchronize(db_);
} else if (name == Slice("fillseq100K")) {
Write(write_sync, SEQUENTIAL, FRESH, num_ / 1000, 100 * 1000, 1);
DBSynchronize(db_);
} else if (name == Slice("readseq")) {
ReadSequential();
} else if (name == Slice("readrandom")) {
ReadRandom();
} else if (name == Slice("readrand100K")) {
int n = reads_;
reads_ /= 1000;
ReadRandom();
reads_ = n;
} else if (name == Slice("readseq100K")) {
int n = reads_;
reads_ /= 1000;
ReadSequential();
reads_ = n;
} else {
known = false;
if (name != Slice()) { // No error message for empty name
fprintf(stderr, "unknown benchmark '%s'\n", name.ToString().c_str());
}
}
if (known) {
Stop(name);
}
}
}
private:
void Open(bool sync) {
assert(db_ == NULL);
// Initialize db_
db_ = new kyotocabinet::TreeDB();
char file_name[100];
db_num_++;
std::string test_dir;
Env::Default()->GetTestDirectory(&test_dir);
snprintf(file_name, sizeof(file_name),
"%s/dbbench_polyDB-%d.kct",
test_dir.c_str(),
db_num_);
// Create tuning options and open the database
int open_options = kyotocabinet::PolyDB::OWRITER |
kyotocabinet::PolyDB::OCREATE;
int tune_options = kyotocabinet::TreeDB::TSMALL |
kyotocabinet::TreeDB::TLINEAR;
if (FLAGS_compression) {
tune_options |= kyotocabinet::TreeDB::TCOMPRESS;
db_->tune_compressor(&comp_);
}
db_->tune_options(tune_options);
db_->tune_page_cache(FLAGS_cache_size);
db_->tune_page(FLAGS_page_size);
db_->tune_map(256LL<<20);
if (sync) {
open_options |= kyotocabinet::PolyDB::OAUTOSYNC;
}
if (!db_->open(file_name, open_options)) {
fprintf(stderr, "open error: %s\n", db_->error().name());
}
}
void Write(bool sync, Order order, DBState state,
int num_entries, int value_size, int entries_per_batch) {
// Create new database if state == FRESH
if (state == FRESH) {
if (FLAGS_use_existing_db) {
message_ = "skipping (--use_existing_db is true)";
return;
}
delete db_;
db_ = NULL;
Open(sync);
Start(); // Do not count time taken to destroy/open
}
if (num_entries != num_) {
char msg[100];
snprintf(msg, sizeof(msg), "(%d ops)", num_entries);
message_ = msg;
}
// Write to database
for (int i = 0; i < num_entries; i++)
{
const int k = (order == SEQUENTIAL) ? i : (rand_.Next() % num_entries);
char key[100];
snprintf(key, sizeof(key), "%016d", k);
bytes_ += value_size + strlen(key);
std::string cpp_key = key;
if (!db_->set(cpp_key, gen_.Generate(value_size).ToString())) {
fprintf(stderr, "set error: %s\n", db_->error().name());
}
FinishedSingleOp();
}
}
void ReadSequential() {
kyotocabinet::DB::Cursor* cur = db_->cursor();
cur->jump();
std::string ckey, cvalue;
while (cur->get(&ckey, &cvalue, true)) {
bytes_ += ckey.size() + cvalue.size();
FinishedSingleOp();
}
delete cur;
}
void ReadRandom() {
std::string value;
for (int i = 0; i < reads_; i++) {
char key[100];
const int k = rand_.Next() % reads_;
snprintf(key, sizeof(key), "%016d", k);
db_->get(key, &value);
FinishedSingleOp();
}
}
};
} // namespace leveldb
int main(int argc, char** argv) {
std::string default_db_path;
for (int i = 1; i < argc; i++) {
double d;
int n;
char junk;
if (leveldb::Slice(argv[i]).starts_with("--benchmarks=")) {
FLAGS_benchmarks = argv[i] + strlen("--benchmarks=");
} else if (sscanf(argv[i], "--compression_ratio=%lf%c", &d, &junk) == 1) {
FLAGS_compression_ratio = d;
} else if (sscanf(argv[i], "--histogram=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_histogram = n;
} else if (sscanf(argv[i], "--num=%d%c", &n, &junk) == 1) {
FLAGS_num = n;
} else if (sscanf(argv[i], "--reads=%d%c", &n, &junk) == 1) {
FLAGS_reads = n;
} else if (sscanf(argv[i], "--value_size=%d%c", &n, &junk) == 1) {
FLAGS_value_size = n;
} else if (sscanf(argv[i], "--cache_size=%d%c", &n, &junk) == 1) {
FLAGS_cache_size = n;
} else if (sscanf(argv[i], "--page_size=%d%c", &n, &junk) == 1) {
FLAGS_page_size = n;
} else if (sscanf(argv[i], "--compression=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_compression = (n == 1) ? true : false;
} else if (strncmp(argv[i], "--db=", 5) == 0) {
FLAGS_db = argv[i] + 5;
} else {
fprintf(stderr, "Invalid flag '%s'\n", argv[i]);
exit(1);
}
}
// Choose a location for the test database if none given with --db=<path>
if (FLAGS_db == NULL) {
leveldb::Env::Default()->GetTestDirectory(&default_db_path);
default_db_path += "/dbbench";
FLAGS_db = default_db_path.c_str();
}
leveldb::Benchmark benchmark;
benchmark.Run();
return 0;
}

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<!DOCTYPE html>
<html>
<head>
<title>LevelDB Benchmarks</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style>
body {
font-family:Helvetica,sans-serif;
padding:20px;
}
h2 {
padding-top:30px;
}
table.bn {
width:800px;
border-collapse:collapse;
border:0;
padding:0;
}
table.bnbase {
width:650px;
}
table.bn td {
padding:2px 0;
}
table.bn td.c1 {
font-weight:bold;
width:150px;
}
table.bn td.c1 div.e {
float:right;
font-weight:normal;
}
table.bn td.c2 {
width:150px;
text-align:right;
padding:2px;
}
table.bn td.c3 {
width:350px;
}
table.bn td.c4 {
width:150px;
font-size:small;
padding-left:4px;
}
/* chart bars */
div.bldb {
background-color:#0255df;
}
div.bkct {
background-color:#df5555;
}
div.bsql {
background-color:#aadf55;
}
.code {
font-family:monospace;
font-size:large;
}
.todo {
color: red;
}
</style>
</head>
<body>
<h1>LevelDB Benchmarks</h1>
<p>Google, July 2011</p>
<hr>
<p>In order to test LevelDB's performance, we benchmark it against other well-established database implementations. We compare LevelDB (revision 39) against <a href="http://www.sqlite.org/">SQLite3</a> (version 3.7.6.3) and <a href="http://fallabs.com/kyotocabinet/spex.html">Kyoto Cabinet's</a> (version 1.2.67) TreeDB (a B+Tree based key-value store). We would like to acknowledge Scott Hess and Mikio Hirabayashi for their suggestions and contributions to the SQLite3 and Kyoto Cabinet benchmarks, respectively.</p>
<p>Benchmarks were all performed on a six-core Intel(R) Xeon(R) CPU X5650 @ 2.67GHz, with 12288 KB of total L3 cache and 12 GB of DDR3 RAM at 1333 MHz. (Note that LevelDB uses at most two CPUs since the benchmarks are single threaded: one to run the benchmark, and one for background compactions.) We ran the benchmarks on two machines (with identical processors), one with an Ext3 file system and one with an Ext4 file system. The machine with the Ext3 file system has a SATA Hitachi HDS721050CLA362 hard drive. The machine with the Ext4 file system has a SATA Samsung HD502HJ hard drive. Both hard drives spin at 7200 RPM and have hard drive write-caching enabled (using `hdparm -W 1 [device]`). The numbers reported below are the median of three measurements.</p>
<h4>Benchmark Source Code</h4>
<p>We wrote benchmark tools for SQLite and Kyoto TreeDB based on LevelDB's <span class="code">db_bench</span>. The code for each of the benchmarks resides here:</p>
<ul>
<li> <b>LevelDB:</b> <a href="http://code.google.com/p/leveldb/source/browse/trunk/db/db_bench.cc">db/db_bench.cc</a>.</li>
<li> <b>SQLite:</b> <a href="http://code.google.com/p/leveldb/source/browse/#svn%2Ftrunk%2Fdoc%2Fbench%2Fdb_bench_sqlite3.cc">doc/bench/db_bench_sqlite3.cc</a>.</li>
<li> <b>Kyoto TreeDB:</b> <a href="http://code.google.com/p/leveldb/source/browse/#svn%2Ftrunk%2Fdoc%2Fbench%2Fdb_bench_tree_db.cc">doc/bench/db_bench_tree_db.cc</a>.</li>
</ul>
<h4>Custom Build Specifications</h4>
<ul>
<li>LevelDB: LevelDB was compiled with the <a href="http://code.google.com/p/google-perftools">tcmalloc</a> library and the <a href="http://code.google.com/p/snappy/">Snappy</a> compression library (revision 33). Assertions were disabled.</li>
<li>TreeDB: TreeDB was compiled using the <a href="http://www.oberhumer.com/opensource/lzo/">LZO</a> compression library (version 2.03). Furthermore, we enabled the TSMALL and TLINEAR options when opening the database in order to reduce the footprint of each record.</li>
<li>SQLite: We tuned SQLite's performance, by setting its locking mode to exclusive. We also enabled SQLite's <a href="http://www.sqlite.org/draft/wal.html">write-ahead logging</a>.</li>
</ul>
<h2>1. Baseline Performance</h2>
<p>This section gives the baseline performance of all the
databases. Following sections show how performance changes as various
parameters are varied. For the baseline:</p>
<ul>
<li> Each database is allowed 4 MB of cache memory.</li>
<li> Databases are opened in <em>asynchronous</em> write mode.
(LevelDB's sync option, TreeDB's OAUTOSYNC option, and
SQLite3's synchronous options are all turned off). I.e.,
every write is pushed to the operating system, but the
benchmark does not wait for the write to reach the disk.</li>
<li> Keys are 16 bytes each.</li>
<li> Value are 100 bytes each (with enough redundancy so that
a simple compressor shrinks them to 50% of their original
size).</li>
<li> Sequential reads/writes traverse the key space in increasing order.</li>
<li> Random reads/writes traverse the key space in random order.</li>
</ul>
<h3>A. Sequential Reads</h3>
<table class="bn bnbase">
<tr><td class="c1">LevelDB</td>
<td class="c2">4,030,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">1,010,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:95px">&nbsp;</div></td>
<tr><td class="c1">SQLite3</td>
<td class="c2">383,000 ops/sec</td>
<td class="c3"><div class="bsql" style="width:33px">&nbsp;</div></td>
</table>
<h3>B. Random Reads</h3>
<table class="bn bnbase">
<tr><td class="c1">LevelDB</td>
<td class="c2">129,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:298px">&nbsp;</div></td>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">151,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:350px">&nbsp;</div></td>
<tr><td class="c1">SQLite3</td>
<td class="c2">134,000 ops/sec</td>
<td class="c3"><div class="bsql" style="width:310px">&nbsp;</div></td>
</table>
<h3>C. Sequential Writes</h3>
<table class="bn bnbase">
<tr><td class="c1">LevelDB</td>
<td class="c2">779,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">342,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:154px">&nbsp;</div></td>
<tr><td class="c1">SQLite3</td>
<td class="c2">48,600 ops/sec</td>
<td class="c3"><div class="bsql" style="width:22px">&nbsp;</div></td>
</table>
<h3>D. Random Writes</h3>
<table class="bn bnbase">
<tr><td class="c1">LevelDB</td>
<td class="c2">164,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">88,500 ops/sec</td>
<td class="c3"><div class="bkct" style="width:188px">&nbsp;</div></td>
<tr><td class="c1">SQLite3</td>
<td class="c2">9,860 ops/sec</td>
<td class="c3"><div class="bsql" style="width:21px">&nbsp;</div></td>
</table>
<p>LevelDB outperforms both SQLite3 and TreeDB in sequential and random write operations and sequential read operations. Kyoto Cabinet has the fastest random read operations.</p>
<h2>2. Write Performance under Different Configurations</h2>
<h3>A. Large Values </h3>
<p>For this benchmark, we start with an empty database, and write 100,000 byte values (~50% compressible). To keep the benchmark running time reasonable, we stop after writing 1000 values.</p>
<h4>Sequential Writes</h4>
<table class="bn bnbase">
<tr><td class="c1">LevelDB</td>
<td class="c2">1,100 ops/sec</td>
<td class="c3"><div class="bldb" style="width:234px">&nbsp;</div></td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">1,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:224px">&nbsp;</div></td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">1,600 ops/sec</td>
<td class="c3"><div class="bsql" style="width:350px">&nbsp;</div></td></tr>
</table>
<h4>Random Writes</h4>
<table class="bn bnbase">
<tr><td class="c1">LevelDB</td>
<td class="c2">480 ops/sec</td>
<td class="c3"><div class="bldb" style="width:105px">&nbsp;</div></td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">1,100 ops/sec</td>
<td class="c3"><div class="bkct" style="width:240px">&nbsp;</div></td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">1,600 ops/sec</td>
<td class="c3"><div class="bsql" style="width:350px">&nbsp;</div></td></tr>
</table>
<p>LevelDB doesn't perform as well with large values of 100,000 bytes each. This is because LevelDB writes keys and values at least twice: first time to the transaction log, and second time (during a compaction) to a sorted file.
With larger values, LevelDB's per-operation efficiency is swamped by the
cost of extra copies of large values.</p>
<h3>B. Batch Writes</h3>
<p>A batch write is a set of writes that are applied atomically to the underlying database. A single batch of N writes may be significantly faster than N individual writes. The following benchmark writes one thousand batches where each batch contains one thousand 100-byte values. TreeDB does not support batch writes and is omitted from this benchmark.</p>
<h4>Sequential Writes</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">840,000 entries/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<td class="c4">(1.08x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">124,000 entries/sec</td>
<td class="c3"><div class="bsql" style="width:52px">&nbsp;</div></td>
<td class="c4">(2.55x baseline)</td></tr>
</table>
<h4>Random Writes</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">221,000 entries/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<td class="c4">(1.35x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">22,000 entries/sec</td>
<td class="c3"><div class="bsql" style="width:34px">&nbsp;</div></td>
<td class="c4">(2.23x baseline)</td></tr>
</table>
<p>Because of the way LevelDB persistent storage is organized, batches of
random writes are not much slower (only a factor of 4x) than batches
of sequential writes.</p>
<h3>C. Synchronous Writes</h3>
<p>In the following benchmark, we enable the synchronous writing modes
of all of the databases. Since this change significantly slows down the
benchmark, we stop after 10,000 writes. For synchronous write tests, we've
disabled hard drive write-caching (using `hdparm -W 0 [device]`).</p>
<ul>
<li>For LevelDB, we set WriteOptions.sync = true.</li>
<li>In TreeDB, we enabled TreeDB's OAUTOSYNC option.</li>
<li>For SQLite3, we set "PRAGMA synchronous = FULL".</li>
</ul>
<h4>Sequential Writes</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">100 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<td class="c4">(0.003x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">7 ops/sec</td>
<td class="c3"><div class="bkct" style="width:27px">&nbsp;</div></td>
<td class="c4">(0.0004x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">88 ops/sec</td>
<td class="c3"><div class="bsql" style="width:315px">&nbsp;</div></td>
<td class="c4">(0.002x baseline)</td></tr>
</table>
<h4>Random Writes</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">100 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<td class="c4">(0.015x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">8 ops/sec</td>
<td class="c3"><div class="bkct" style="width:29px">&nbsp;</div></td>
<td class="c4">(0.001x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">88 ops/sec</td>
<td class="c3"><div class="bsql" style="width:314px">&nbsp;</div></td>
<td class="c4">(0.009x baseline)</td></tr>
</table>
<p>Also see the <code>ext4</code> performance numbers below
since synchronous writes behave significantly differently
on <code>ext3</code> and <code>ext4</code>.</p>
<h3>D. Turning Compression Off</h3>
<p>In the baseline measurements, LevelDB and TreeDB were using
light-weight compression
(<a href="http://code.google.com/p/snappy/">Snappy</a> for LevelDB,
and <a href="http://www.oberhumer.com/opensource/lzo/">LZO</a> for
TreeDB). SQLite3, by default does not use compression. The
experiments below show what happens when compression is disabled in
all of the databases (the SQLite3 numbers are just a copy of
its baseline measurements):</p>
<h4>Sequential Writes</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">594,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<td class="c4">(0.76x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">485,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:239px">&nbsp;</div></td>
<td class="c4">(1.42x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">48,600 ops/sec</td>
<td class="c3"><div class="bsql" style="width:29px">&nbsp;</div></td>
<td class="c4">(1.00x baseline)</td></tr>
</table>
<h4>Random Writes</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">135,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:296px">&nbsp;</div></td>
<td class="c4">(0.82x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">159,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:350px">&nbsp;</div></td>
<td class="c4">(1.80x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">9,860 ops/sec</td>
<td class="c3"><div class="bsql" style="width:22px">&nbsp;</div></td>
<td class="c4">(1.00x baseline)</td></tr>
</table>
<p>LevelDB's write performance is better with compression than without
since compression decreases the amount of data that has to be written
to disk. Therefore LevelDB users can leave compression enabled in
most scenarios without having worry about a tradeoff between space
usage and performance. TreeDB's performance on the other hand is
better without compression than with compression. Presumably this is
because TreeDB's compression library (LZO) is more expensive than
LevelDB's compression library (Snappy).<p>
<h3>E. Using More Memory</h3>
<p>We increased the overall cache size for each database to 128 MB. For LevelDB, we partitioned 128 MB into a 120 MB write buffer and 8 MB of cache (up from 2 MB of write buffer and 2 MB of cache). For SQLite3, we kept the page size at 1024 bytes, but increased the number of pages to 131,072 (up from 4096). For TreeDB, we also kept the page size at 1024 bytes, but increased the cache size to 128 MB (up from 4 MB).</p>
<h4>Sequential Writes</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">812,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<td class="c4">(1.04x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">321,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:138px">&nbsp;</div></td>
<td class="c4">(0.94x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">48,500 ops/sec</td>
<td class="c3"><div class="bsql" style="width:21px">&nbsp;</div></td>
<td class="c4">(1.00x baseline)</td></tr>
</table>
<h4>Random Writes</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">355,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<td class="c4">(2.16x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">284,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:280px">&nbsp;</div></td>
<td class="c4">(3.21x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">9,670 ops/sec</td>
<td class="c3"><div class="bsql" style="width:10px">&nbsp;</div></td>
<td class="c4">(0.98x baseline)</td></tr>
</table>
<p>SQLite's performance does not change substantially when compared to
the baseline, but the random write performance for both LevelDB and
TreeDB increases significantly. LevelDB's performance improves
because a larger write buffer reduces the need to merge sorted files
(since it creates a smaller number of larger sorted files). TreeDB's
performance goes up because the entire database is available in memory
for fast in-place updates.</p>
<h2>3. Read Performance under Different Configurations</h2>
<h3>A. Larger Caches</h3>
<p>We increased the overall memory usage to 128 MB for each database.
For LevelDB, we allocated 8 MB to LevelDB's write buffer and 120 MB
to LevelDB's cache. The other databases don't differentiate between a
write buffer and a cache, so we simply set their cache size to 128
MB.</p>
<h4>Sequential Reads</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">5,210,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<td class="c4">(1.29x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">1,070,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:72px">&nbsp;</div></td>
<td class="c4">(1.06x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">609,000 ops/sec</td>
<td class="c3"><div class="bsql" style="width:41px">&nbsp;</div></td>
<td class="c4">(1.59x baseline)</td></tr>
</table>
<h4>Random Reads</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">190,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:144px">&nbsp;</div></td>
<td class="c4">(1.47x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">463,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:350px">&nbsp;</div></td>
<td class="c4">(3.07x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">186,000 ops/sec</td>
<td class="c3"><div class="bsql" style="width:141px">&nbsp;</div></td>
<td class="c4">(1.39x baseline)</td></tr>
</table>
<p>As expected, the read performance of all of the databases increases
when the caches are enlarged. In particular, TreeDB seems to make
very effective use of a cache that is large enough to hold the entire
database.</p>
<h3>B. No Compression Reads </h3>
<p>For this benchmark, we populated a database with 1 million entries consisting of 16 byte keys and 100 byte values. We compiled LevelDB and Kyoto Cabinet without compression support, so results that are read out from the database are already uncompressed. We've listed the SQLite3 baseline read performance as a point of comparison.</p>
<h4>Sequential Reads</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">4,880,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:350px">&nbsp;</div></td>
<td class="c4">(1.21x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">1,230,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:88px">&nbsp;</div></td>
<td class="c4">(3.60x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">383,000 ops/sec</td>
<td class="c3"><div class="bsql" style="width:27px">&nbsp;</div></td>
<td class="c4">(1.00x baseline)</td></tr>
</table>
<h4>Random Reads</h4>
<table class="bn">
<tr><td class="c1">LevelDB</td>
<td class="c2">149,000 ops/sec</td>
<td class="c3"><div class="bldb" style="width:300px">&nbsp;</div></td>
<td class="c4">(1.16x baseline)</td></tr>
<tr><td class="c1">Kyoto TreeDB</td>
<td class="c2">175,000 ops/sec</td>
<td class="c3"><div class="bkct" style="width:350px">&nbsp;</div></td>
<td class="c4">(1.16x baseline)</td></tr>
<tr><td class="c1">SQLite3</td>
<td class="c2">134,000 ops/sec</td>
<td class="c3"><div class="bsql" style="width:268px">&nbsp;</div></td>
<td class="c4">(1.00x baseline)</td></tr>
</table>
<p>Performance of both LevelDB and TreeDB improves a small amount when
compression is disabled. Note however that under different workloads,
performance may very well be better with compression if it allows more
of the working set to fit in memory.</p>
<h2>Note about Ext4 Filesystems</h2>
<p>The preceding numbers are for an ext3 file system. Synchronous writes are much slower under <a href="http://en.wikipedia.org/wiki/Ext4">ext4</a> (LevelDB drops to ~31 writes / second and TreeDB drops to ~5 writes / second; SQLite3's synchronous writes do not noticeably drop) due to ext4's different handling of <span class="code">fsync</span> / <span class="code">msync</span> calls. Even LevelDB's asynchronous write performance drops somewhat since it spreads its storage across multiple files and issues <span class="code">fsync</span> calls when switching to a new file.</p>
<h2>Acknowledgements</h2>
<p>Jeff Dean and Sanjay Ghemawat wrote LevelDB. Kevin Tseng wrote and compiled these benchmarks. Mikio Hirabayashi, Scott Hess, and Gabor Cselle provided help and advice.</p>
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<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="doc.css" />
<title>Leveldb file layout and compactions</title>
</head>
<body>
<h1>Files</h1>
The implementation of leveldb is similar in spirit to the
representation of a single
<a href="http://labs.google.com/papers/bigtable.html">
Bigtable tablet (section 5.3)</a>.
However the organization of the files that make up the representation
is somewhat different and is explained below.
<p>
Each database is represented by a set of files stored in a directory.
There are several different types of files as documented below:
<p>
<h2>Log files</h2>
<p>
A log file (*.log) stores a sequence of recent updates. Each update
is appended to the current log file. When the log file reaches a
pre-determined size (approximately 4MB by default), it is converted
to a sorted table (see below) and a new log file is created for future
updates.
<p>
A copy of the current log file is kept in an in-memory structure (the
<code>memtable</code>). This copy is consulted on every read so that read
operations reflect all logged updates.
<p>
<h2>Sorted tables</h2>
<p>
A sorted table (*.sst) stores a sequence of entries sorted by key.
Each entry is either a value for the key, or a deletion marker for the
key. (Deletion markers are kept around to hide obsolete values
present in older sorted tables).
<p>
The set of sorted tables are organized into a sequence of levels. The
sorted table generated from a log file is placed in a special <code>young</code>
level (also called level-0). When the number of young files exceeds a
certain threshold (currently four), all of the young files are merged
together with all of the overlapping level-1 files to produce a
sequence of new level-1 files (we create a new level-1 file for every
2MB of data.)
<p>
Files in the young level may contain overlapping keys. However files
in other levels have distinct non-overlapping key ranges. Consider
level number L where L >= 1. When the combined size of files in
level-L exceeds (10^L) MB (i.e., 10MB for level-1, 100MB for level-2,
...), one file in level-L, and all of the overlapping files in
level-(L+1) are merged to form a set of new files for level-(L+1).
These merges have the effect of gradually migrating new updates from
the young level to the largest level using only bulk reads and writes
(i.e., minimizing expensive seeks).
<h2>Manifest</h2>
<p>
A MANIFEST file lists the set of sorted tables that make up each
level, the corresponding key ranges, and other important metadata.
A new MANIFEST file (with a new number embedded in the file name)
is created whenever the database is reopened. The MANIFEST file is
formatted as a log, and changes made to the serving state (as files
are added or removed) are appended to this log.
<p>
<h2>Current</h2>
<p>
CURRENT is a simple text file that contains the name of the latest
MANIFEST file.
<p>
<h2>Info logs</h2>
<p>
Informational messages are printed to files named LOG and LOG.old.
<p>
<h2>Others</h2>
<p>
Other files used for miscellaneous purposes may also be present
(LOCK, *.dbtmp).
<h1>Level 0</h1>
When the log file grows above a certain size (1MB by default):
<ul>
<li>Create a brand new memtable and log file and direct future updates here
<li>In the background:
<ul>
<li>Write the contents of the previous memtable to an sstable
<li>Discard the memtable
<li>Delete the old log file and the old memtable
<li>Add the new sstable to the young (level-0) level.
</ul>
</ul>
<h1>Compactions</h1>
<p>
When the size of level L exceeds its limit, we compact it in a
background thread. The compaction picks a file from level L and all
overlapping files from the next level L+1. Note that if a level-L
file overlaps only part of a level-(L+1) file, the entire file at
level-(L+1) is used as an input to the compaction and will be
discarded after the compaction. Aside: because level-0 is special
(files in it may overlap each other), we treat compactions from
level-0 to level-1 specially: a level-0 compaction may pick more than
one level-0 file in case some of these files overlap each other.
<p>
A compaction merges the contents of the picked files to produce a
sequence of level-(L+1) files. We switch to producing a new
level-(L+1) file after the current output file has reached the target
file size (2MB). We also switch to a new output file when the key
range of the current output file has grown enough to overlap more then
ten level-(L+2) files. This last rule ensures that a later compaction
of a level-(L+1) file will not pick up too much data from level-(L+2).
<p>
The old files are discarded and the new files are added to the serving
state.
<p>
Compactions for a particular level rotate through the key space. In
more detail, for each level L, we remember the ending key of the last
compaction at level L. The next compaction for level L will pick the
first file that starts after this key (wrapping around to the
beginning of the key space if there is no such file).
<p>
Compactions drop overwritten values. They also drop deletion markers
if there are no higher numbered levels that contain a file whose range
overlaps the current key.
<h2>Timing</h2>
Level-0 compactions will read up to four 1MB files from level-0, and
at worst all the level-1 files (10MB). I.e., we will read 14MB and
write 14MB.
<p>
Other than the special level-0 compactions, we will pick one 2MB file
from level L. In the worst case, this will overlap ~ 12 files from
level L+1 (10 because level-(L+1) is ten times the size of level-L,
and another two at the boundaries since the file ranges at level-L
will usually not be aligned with the file ranges at level-L+1). The
compaction will therefore read 26MB and write 26MB. Assuming a disk
IO rate of 100MB/s (ballpark range for modern drives), the worst
compaction cost will be approximately 0.5 second.
<p>
If we throttle the background writing to something small, say 10% of
the full 100MB/s speed, a compaction may take up to 5 seconds. If the
user is writing at 10MB/s, we might build up lots of level-0 files
(~50 to hold the 5*10MB). This may signficantly increase the cost of
reads due to the overhead of merging more files together on every
read.
<p>
Solution 1: To reduce this problem, we might want to increase the log
switching threshold when the number of level-0 files is large. Though
the downside is that the larger this threshold, the more memory we will
need to hold the corresponding memtable.
<p>
Solution 2: We might want to decrease write rate artificially when the
number of level-0 files goes up.
<p>
Solution 3: We work on reducing the cost of very wide merges.
Perhaps most of the level-0 files will have their blocks sitting
uncompressed in the cache and we will only need to worry about the
O(N) complexity in the merging iterator.
<h2>Number of files</h2>
Instead of always making 2MB files, we could make larger files for
larger levels to reduce the total file count, though at the expense of
more bursty compactions. Alternatively, we could shard the set of
files into multiple directories.
<p>
An experiment on an <code>ext3</code> filesystem on Feb 04, 2011 shows
the following timings to do 100K file opens in directories with
varying number of files:
<table class="datatable">
<tr><th>Files in directory</th><th>Microseconds to open a file</th></tr>
<tr><td>1000</td><td>9</td>
<tr><td>10000</td><td>10</td>
<tr><td>100000</td><td>16</td>
</table>
So maybe even the sharding is not necessary on modern filesystems?
<h1>Recovery</h1>
<ul>
<li> Read CURRENT to find name of the latest committed MANIFEST
<li> Read the named MANIFEST file
<li> Clean up stale files
<li> We could open all sstables here, but it is probably better to be lazy...
<li> Convert log chunk to a new level-0 sstable
<li> Start directing new writes to a new log file with recovered sequence#
</ul>
<h1>Garbage collection of files</h1>
<code>DeleteObsoleteFiles()</code> is called at the end of every
compaction and at the end of recovery. It finds the names of all
files in the database. It deletes all log files that are not the
current log file. It deletes all table files that are not referenced
from some level and are not the output of an active compaction.
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<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="doc.css" />
<title>Leveldb</title>
</head>
<body>
<h1>Leveldb</h1>
<address>Jeff Dean, Sanjay Ghemawat</address>
<p>
The <code>leveldb</code> library provides a persistent key value store. Keys and
values are arbitrary byte arrays. The keys are ordered within the key
value store according to a user-specified comparator function.
<p>
<h1>Opening A Database</h1>
<p>
A <code>leveldb</code> database has a name which corresponds to a file system
directory. All of the contents of database are stored in this
directory. The following example shows how to open a database,
creating it if necessary:
<p>
<pre>
#include &lt;assert&gt;
#include "leveldb/db.h"
leveldb::DB* db;
leveldb::Options options;
options.create_if_missing = true;
leveldb::Status status = leveldb::DB::Open(options, "/tmp/testdb", &amp;db);
assert(status.ok());
...
</pre>
If you want to raise an error if the database already exists, add
the following line before the <code>leveldb::DB::Open</code> call:
<pre>
options.error_if_exists = true;
</pre>
<h1>Status</h1>
<p>
You may have noticed the <code>leveldb::Status</code> type above. Values of this
type are returned by most functions in <code>leveldb</code> that may encounter an
error. You can check if such a result is ok, and also print an
associated error message:
<p>
<pre>
leveldb::Status s = ...;
if (!s.ok()) cerr &lt;&lt; s.ToString() &lt;&lt; endl;
</pre>
<h1>Closing A Database</h1>
<p>
When you are done with a database, just delete the database object.
Example:
<p>
<pre>
... open the db as described above ...
... do something with db ...
delete db;
</pre>
<h1>Reads And Writes</h1>
<p>
The database provides <code>Put</code>, <code>Delete</code>, and <code>Get</code> methods to
modify/query the database. For example, the following code
moves the value stored under key1 to key2.
<pre>
std::string value;
leveldb::Status s = db-&gt;Get(leveldb::ReadOptions(), key1, &amp;value);
if (s.ok()) s = db-&gt;Put(leveldb::WriteOptions(), key2, value);
if (s.ok()) s = db-&gt;Delete(leveldb::WriteOptions(), key1);
</pre>
<h1>Atomic Updates</h1>
<p>
Note that if the process dies after the Put of key2 but before the
delete of key1, the same value may be left stored under multiple keys.
Such problems can be avoided by using the <code>WriteBatch</code> class to
atomically apply a set of updates:
<p>
<pre>
#include "leveldb/write_batch.h"
...
std::string value;
leveldb::Status s = db-&gt;Get(leveldb::ReadOptions(), key1, &amp;value);
if (s.ok()) {
leveldb::WriteBatch batch;
batch.Delete(key1);
batch.Put(key2, value);
s = db-&gt;Write(leveldb::WriteOptions(), &amp;batch);
}
</pre>
The <code>WriteBatch</code> holds a sequence of edits to be made to the database,
and these edits within the batch are applied in order. Note that we
called <code>Delete</code> before <code>Put</code> so that if <code>key1</code> is identical to <code>key2</code>,
we do not end up erroneously dropping the value entirely.
<p>
Apart from its atomicity benefits, <code>WriteBatch</code> may also be used to
speed up bulk updates by placing lots of individual mutations into the
same batch.
<h1>Synchronous Writes</h1>
By default, each write to <code>leveldb</code> is asynchronous: it
returns after pushing the write from the process into the operating
system. The transfer from operating system memory to the underlying
persistent storage happens asynchronously. The <code>sync</code> flag
can be turned on for a particular write to make the write operation
not return until the data being written has been pushed all the way to
persistent storage. (On Posix systems, this is implemented by calling
either <code>fsync(...)</code> or <code>fdatasync(...)</code> or
<code>msync(..., MS_SYNC)</code> before the write operation returns.)
<pre>
leveldb::WriteOptions write_options;
write_options.sync = true;
db-&gt;Put(write_options, ...);
</pre>
Asynchronous writes are often more than a thousand times as fast as
synchronous writes. The downside of asynchronous writes is that a
crash of the machine may cause the last few updates to be lost. Note
that a crash of just the writing process (i.e., not a reboot) will not
cause any loss since even when <code>sync</code> is false, an update
is pushed from the process memory into the operating system before it
is considered done.
<p>
Asynchronous writes can often be used safely. For example, when
loading a large amount of data into the database you can handle lost
updates by restarting the bulk load after a crash. A hybrid scheme is
also possible where every Nth write is synchronous, and in the event
of a crash, the bulk load is restarted just after the last synchronous
write finished by the previous run. (The synchronous write can update
a marker that describes where to restart on a crash.)
<p>
<code>WriteBatch</code> provides an alternative to asynchronous writes.
Multiple updates may be placed in the same <code>WriteBatch</code> and
applied together using a synchronous write (i.e.,
<code>write_options.sync</code> is set to true). The extra cost of
the synchronous write will be amortized across all of the writes in
the batch.
<p>
<h1>Concurrency</h1>
<p>
A database may only be opened by one process at a time.
The <code>leveldb</code> implementation acquires a lock from the
operating system to prevent misuse. Within a single process, the
same <code>leveldb::DB</code> object may be safely shared by multiple
concurrent threads. I.e., different threads may write into or fetch
iterators or call <code>Get</code> on the same database without any
external synchronization (the leveldb implementation will
automatically do the required synchronization). However other objects
(like Iterator and WriteBatch) may require external synchronization.
If two threads share such an object, they must protect access to it
using their own locking protocol. More details are available in
the public header files.
<p>
<h1>Iteration</h1>
<p>
The following example demonstrates how to print all key,value pairs
in a database.
<p>
<pre>
leveldb::Iterator* it = db-&gt;NewIterator(leveldb::ReadOptions());
for (it-&gt;SeekToFirst(); it-&gt;Valid(); it-&gt;Next()) {
cout &lt;&lt; it-&gt;key().ToString() &lt;&lt; ": " &lt;&lt; it-&gt;value().ToString() &lt;&lt; endl;
}
assert(it-&gt;status().ok()); // Check for any errors found during the scan
delete it;
</pre>
The following variation shows how to process just the keys in the
range <code>[start,limit)</code>:
<p>
<pre>
for (it-&gt;Seek(start);
it-&gt;Valid() &amp;&amp; it-&gt;key().ToString() &lt; limit;
it-&gt;Next()) {
...
}
</pre>
You can also process entries in reverse order. (Caveat: reverse
iteration may be somewhat slower than forward iteration.)
<p>
<pre>
for (it-&gt;SeekToLast(); it-&gt;Valid(); it-&gt;Prev()) {
...
}
</pre>
<h1>Snapshots</h1>
<p>
Snapshots provide consistent read-only views over the entire state of
the key-value store. <code>ReadOptions::snapshot</code> may be non-NULL to indicate
that a read should operate on a particular version of the DB state.
If <code>ReadOptions::snapshot</code> is NULL, the read will operate on an
implicit snapshot of the current state.
<p>
Snapshots are created by the DB::GetSnapshot() method:
<p>
<pre>
leveldb::ReadOptions options;
options.snapshot = db-&gt;GetSnapshot();
... apply some updates to db ...
leveldb::Iterator* iter = db-&gt;NewIterator(options);
... read using iter to view the state when the snapshot was created ...
delete iter;
db-&gt;ReleaseSnapshot(options.snapshot);
</pre>
Note that when a snapshot is no longer needed, it should be released
using the DB::ReleaseSnapshot interface. This allows the
implementation to get rid of state that was being maintained just to
support reading as of that snapshot.
<h1>Slice</h1>
<p>
The return value of the <code>it->key()</code> and <code>it->value()</code> calls above
are instances of the <code>leveldb::Slice</code> type. <code>Slice</code> is a simple
structure that contains a length and a pointer to an external byte
array. Returning a <code>Slice</code> is a cheaper alternative to returning a
<code>std::string</code> since we do not need to copy potentially large keys and
values. In addition, <code>leveldb</code> methods do not return null-terminated
C-style strings since <code>leveldb</code> keys and values are allowed to
contain '\0' bytes.
<p>
C++ strings and null-terminated C-style strings can be easily converted
to a Slice:
<p>
<pre>
leveldb::Slice s1 = "hello";
std::string str("world");
leveldb::Slice s2 = str;
</pre>
A Slice can be easily converted back to a C++ string:
<pre>
std::string str = s1.ToString();
assert(str == std::string("hello"));
</pre>
Be careful when using Slices since it is up to the caller to ensure that
the external byte array into which the Slice points remains live while
the Slice is in use. For example, the following is buggy:
<p>
<pre>
leveldb::Slice slice;
if (...) {
std::string str = ...;
slice = str;
}
Use(slice);
</pre>
When the <code>if</code> statement goes out of scope, <code>str</code> will be destroyed and the
backing storage for <code>slice</code> will disappear.
<p>
<h1>Comparators</h1>
<p>
The preceding examples used the default ordering function for key,
which orders bytes lexicographically. You can however supply a custom
comparator when opening a database. For example, suppose each
database key consists of two numbers and we should sort by the first
number, breaking ties by the second number. First, define a proper
subclass of <code>leveldb::Comparator</code> that expresses these rules:
<p>
<pre>
class TwoPartComparator : public leveldb::Comparator {
public:
// Three-way comparison function:
// if a &lt; b: negative result
// if a &gt; b: positive result
// else: zero result
int Compare(const leveldb::Slice&amp; a, const leveldb::Slice&amp; b) const {
int a1, a2, b1, b2;
ParseKey(a, &amp;a1, &amp;a2);
ParseKey(b, &amp;b1, &amp;b2);
if (a1 &lt; b1) return -1;
if (a1 &gt; b1) return +1;
if (a2 &lt; b2) return -1;
if (a2 &gt; b2) return +1;
return 0;
}
// Ignore the following methods for now:
const char* Name() const { return "TwoPartComparator"; }
void FindShortestSeparator(std::string*, const leveldb::Slice&amp;) const { }
void FindShortSuccessor(std::string*) const { }
};
</pre>
Now create a database using this custom comparator:
<p>
<pre>
TwoPartComparator cmp;
leveldb::DB* db;
leveldb::Options options;
options.create_if_missing = true;
options.comparator = &amp;cmp;
leveldb::Status status = leveldb::DB::Open(options, "/tmp/testdb", &amp;db);
...
</pre>
<h2>Backwards compatibility</h2>
<p>
The result of the comparator's <code>Name</code> method is attached to the
database when it is created, and is checked on every subsequent
database open. If the name changes, the <code>leveldb::DB::Open</code> call will
fail. Therefore, change the name if and only if the new key format
and comparison function are incompatible with existing databases, and
it is ok to discard the contents of all existing databases.
<p>
You can however still gradually evolve your key format over time with
a little bit of pre-planning. For example, you could store a version
number at the end of each key (one byte should suffice for most uses).
When you wish to switch to a new key format (e.g., adding an optional
third part to the keys processed by <code>TwoPartComparator</code>),
(a) keep the same comparator name (b) increment the version number
for new keys (c) change the comparator function so it uses the
version numbers found in the keys to decide how to interpret them.
<p>
<h1>Performance</h1>
<p>
Performance can be tuned by changing the default values of the
types defined in <code>include/leveldb/options.h</code>.
<p>
<h2>Block size</h2>
<p>
<code>leveldb</code> groups adjacent keys together into the same block and such a
block is the unit of transfer to and from persistent storage. The
default block size is approximately 4096 uncompressed bytes.
Applications that mostly do bulk scans over the contents of the
database may wish to increase this size. Applications that do a lot
of point reads of small values may wish to switch to a smaller block
size if performance measurements indicate an improvement. There isn't
much benefit in using blocks smaller than one kilobyte, or larger than
a few megabytes. Also note that compression will be more effective
with larger block sizes.
<p>
<h2>Compression</h2>
<p>
Each block is individually compressed before being written to
persistent storage. Compression is on by default since the default
compression method is very fast, and is automatically disabled for
uncompressible data. In rare cases, applications may want to disable
compression entirely, but should only do so if benchmarks show a
performance improvement:
<p>
<pre>
leveldb::Options options;
options.compression = leveldb::kNoCompression;
... leveldb::DB::Open(options, name, ...) ....
</pre>
<h2>Cache</h2>
<p>
The contents of the database are stored in a set of files in the
filesystem and each file stores a sequence of compressed blocks. If
<code>options.cache</code> is non-NULL, it is used to cache frequently used
uncompressed block contents.
<p>
<pre>
#include "leveldb/cache.h"
leveldb::Options options;
options.cache = leveldb::NewLRUCache(100 * 1048576); // 100MB cache
leveldb::DB* db;
leveldb::DB::Open(options, name, &db);
... use the db ...
delete db
delete options.cache;
</pre>
Note that the cache holds uncompressed data, and therefore it should
be sized according to application level data sizes, without any
reduction from compression. (Caching of compressed blocks is left to
the operating system buffer cache, or any custom <code>Env</code>
implementation provided by the client.)
<p>
When performing a bulk read, the application may wish to disable
caching so that the data processed by the bulk read does not end up
displacing most of the cached contents. A per-iterator option can be
used to achieve this:
<p>
<pre>
leveldb::ReadOptions options;
options.fill_cache = false;
leveldb::Iterator* it = db-&gt;NewIterator(options);
for (it-&gt;SeekToFirst(); it-&gt;Valid(); it-&gt;Next()) {
...
}
</pre>
<h2>Key Layout</h2>
<p>
Note that the unit of disk transfer and caching is a block. Adjacent
keys (according to the database sort order) will usually be placed in
the same block. Therefore the application can improve its performance
by placing keys that are accessed together near each other and placing
infrequently used keys in a separate region of the key space.
<p>
For example, suppose we are implementing a simple file system on top
of <code>leveldb</code>. The types of entries we might wish to store are:
<p>
<pre>
filename -&gt; permission-bits, length, list of file_block_ids
file_block_id -&gt; data
</pre>
We might want to prefix <code>filename</code> keys with one letter (say '/') and the
<code>file_block_id</code> keys with a different letter (say '0') so that scans
over just the metadata do not force us to fetch and cache bulky file
contents.
<p>
<h2>Filters</h2>
<p>
Because of the way <code>leveldb</code> data is organized on disk,
a single <code>Get()</code> call may involve multiple reads from disk.
The optional <code>FilterPolicy</code> mechanism can be used to reduce
the number of disk reads substantially.
<pre>
leveldb::Options options;
options.filter_policy = NewBloomFilterPolicy(10);
leveldb::DB* db;
leveldb::DB::Open(options, "/tmp/testdb", &amp;db);
... use the database ...
delete db;
delete options.filter_policy;
</pre>
The preceding code associates a
<a href="http://en.wikipedia.org/wiki/Bloom_filter">Bloom filter</a>
based filtering policy with the database. Bloom filter based
filtering relies on keeping some number of bits of data in memory per
key (in this case 10 bits per key since that is the argument we passed
to NewBloomFilterPolicy). This filter will reduce the number of unnecessary
disk reads needed for <code>Get()</code> calls by a factor of
approximately a 100. Increasing the bits per key will lead to a
larger reduction at the cost of more memory usage. We recommend that
applications whose working set does not fit in memory and that do a
lot of random reads set a filter policy.
<p>
If you are using a custom comparator, you should ensure that the filter
policy you are using is compatible with your comparator. For example,
consider a comparator that ignores trailing spaces when comparing keys.
<code>NewBloomFilterPolicy</code> must not be used with such a comparator.
Instead, the application should provide a custom filter policy that
also ignores trailing spaces. For example:
<pre>
class CustomFilterPolicy : public leveldb::FilterPolicy {
private:
FilterPolicy* builtin_policy_;
public:
CustomFilterPolicy() : builtin_policy_(NewBloomFilterPolicy(10)) { }
~CustomFilterPolicy() { delete builtin_policy_; }
const char* Name() const { return "IgnoreTrailingSpacesFilter"; }
void CreateFilter(const Slice* keys, int n, std::string* dst) const {
// Use builtin bloom filter code after removing trailing spaces
std::vector&lt;Slice&gt; trimmed(n);
for (int i = 0; i &lt; n; i++) {
trimmed[i] = RemoveTrailingSpaces(keys[i]);
}
return builtin_policy_-&gt;CreateFilter(&amp;trimmed[i], n, dst);
}
bool KeyMayMatch(const Slice& key, const Slice& filter) const {
// Use builtin bloom filter code after removing trailing spaces
return builtin_policy_-&gt;KeyMayMatch(RemoveTrailingSpaces(key), filter);
}
};
</pre>
<p>
Advanced applications may provide a filter policy that does not use
a bloom filter but uses some other mechanism for summarizing a set
of keys. See <code>leveldb/filter_policy.h</code> for detail.
<p>
<h1>Checksums</h1>
<p>
<code>leveldb</code> associates checksums with all data it stores in the file system.
There are two separate controls provided over how aggressively these
checksums are verified:
<p>
<ul>
<li> <code>ReadOptions::verify_checksums</code> may be set to true to force
checksum verification of all data that is read from the file system on
behalf of a particular read. By default, no such verification is
done.
<p>
<li> <code>Options::paranoid_checks</code> may be set to true before opening a
database to make the database implementation raise an error as soon as
it detects an internal corruption. Depending on which portion of the
database has been corrupted, the error may be raised when the database
is opened, or later by another database operation. By default,
paranoid checking is off so that the database can be used even if
parts of its persistent storage have been corrupted.
<p>
If a database is corrupted (perhaps it cannot be opened when
paranoid checking is turned on), the <code>leveldb::RepairDB</code> function
may be used to recover as much of the data as possible
<p>
</ul>
<h1>Approximate Sizes</h1>
<p>
The <code>GetApproximateSizes</code> method can used to get the approximate
number of bytes of file system space used by one or more key ranges.
<p>
<pre>
leveldb::Range ranges[2];
ranges[0] = leveldb::Range("a", "c");
ranges[1] = leveldb::Range("x", "z");
uint64_t sizes[2];
leveldb::Status s = db-&gt;GetApproximateSizes(ranges, 2, sizes);
</pre>
The preceding call will set <code>sizes[0]</code> to the approximate number of
bytes of file system space used by the key range <code>[a..c)</code> and
<code>sizes[1]</code> to the approximate number of bytes used by the key range
<code>[x..z)</code>.
<p>
<h1>Environment</h1>
<p>
All file operations (and other operating system calls) issued by the
<code>leveldb</code> implementation are routed through a <code>leveldb::Env</code> object.
Sophisticated clients may wish to provide their own <code>Env</code>
implementation to get better control. For example, an application may
introduce artificial delays in the file IO paths to limit the impact
of <code>leveldb</code> on other activities in the system.
<p>
<pre>
class SlowEnv : public leveldb::Env {
.. implementation of the Env interface ...
};
SlowEnv env;
leveldb::Options options;
options.env = &amp;env;
Status s = leveldb::DB::Open(options, ...);
</pre>
<h1>Porting</h1>
<p>
<code>leveldb</code> may be ported to a new platform by providing platform
specific implementations of the types/methods/functions exported by
<code>leveldb/port/port.h</code>. See <code>leveldb/port/port_example.h</code> for more
details.
<p>
In addition, the new platform may need a new default <code>leveldb::Env</code>
implementation. See <code>leveldb/util/env_posix.h</code> for an example.
<h1>Other Information</h1>
<p>
Details about the <code>leveldb</code> implementation may be found in
the following documents:
<ul>
<li> <a href="impl.html">Implementation notes</a>
<li> <a href="table_format.txt">Format of an immutable Table file</a>
<li> <a href="log_format.txt">Format of a log file</a>
</ul>
</body>
</html>

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The log file contents are a sequence of 32KB blocks. The only
exception is that the tail of the file may contain a partial block.
Each block consists of a sequence of records:
block := record* trailer?
record :=
checksum: uint32 // crc32c of type and data[] ; little-endian
length: uint16 // little-endian
type: uint8 // One of FULL, FIRST, MIDDLE, LAST
data: uint8[length]
A record never starts within the last six bytes of a block (since it
won't fit). Any leftover bytes here form the trailer, which must
consist entirely of zero bytes and must be skipped by readers.
Aside: if exactly seven bytes are left in the current block, and a new
non-zero length record is added, the writer must emit a FIRST record
(which contains zero bytes of user data) to fill up the trailing seven
bytes of the block and then emit all of the user data in subsequent
blocks.
More types may be added in the future. Some Readers may skip record
types they do not understand, others may report that some data was
skipped.
FULL == 1
FIRST == 2
MIDDLE == 3
LAST == 4
The FULL record contains the contents of an entire user record.
FIRST, MIDDLE, LAST are types used for user records that have been
split into multiple fragments (typically because of block boundaries).
FIRST is the type of the first fragment of a user record, LAST is the
type of the last fragment of a user record, and MID is the type of all
interior fragments of a user record.
Example: consider a sequence of user records:
A: length 1000
B: length 97270
C: length 8000
A will be stored as a FULL record in the first block.
B will be split into three fragments: first fragment occupies the rest
of the first block, second fragment occupies the entirety of the
second block, and the third fragment occupies a prefix of the third
block. This will leave six bytes free in the third block, which will
be left empty as the trailer.
C will be stored as a FULL record in the fourth block.
===================
Some benefits over the recordio format:
(1) We do not need any heuristics for resyncing - just go to next
block boundary and scan. If there is a corruption, skip to the next
block. As a side-benefit, we do not get confused when part of the
contents of one log file are embedded as a record inside another log
file.
(2) Splitting at approximate boundaries (e.g., for mapreduce) is
simple: find the next block boundary and skip records until we
hit a FULL or FIRST record.
(3) We do not need extra buffering for large records.
Some downsides compared to recordio format:
(1) No packing of tiny records. This could be fixed by adding a new
record type, so it is a shortcoming of the current implementation,
not necessarily the format.
(2) No compression. Again, this could be fixed by adding new record types.

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File format
===========
<beginning_of_file>
[data block 1]
[data block 2]
...
[data block N]
[meta block 1]
...
[meta block K]
[metaindex block]
[index block]
[Footer] (fixed size; starts at file_size - sizeof(Footer))
<end_of_file>
The file contains internal pointers. Each such pointer is called
a BlockHandle and contains the following information:
offset: varint64
size: varint64
See https://developers.google.com/protocol-buffers/docs/encoding#varints
for an explanation of varint64 format.
(1) The sequence of key/value pairs in the file are stored in sorted
order and partitioned into a sequence of data blocks. These blocks
come one after another at the beginning of the file. Each data block
is formatted according to the code in block_builder.cc, and then
optionally compressed.
(2) After the data blocks we store a bunch of meta blocks. The
supported meta block types are described below. More meta block types
may be added in the future. Each meta block is again formatted using
block_builder.cc and then optionally compressed.
(3) A "metaindex" block. It contains one entry for every other meta
block where the key is the name of the meta block and the value is a
BlockHandle pointing to that meta block.
(4) An "index" block. This block contains one entry per data block,
where the key is a string >= last key in that data block and before
the first key in the successive data block. The value is the
BlockHandle for the data block.
(6) At the very end of the file is a fixed length footer that contains
the BlockHandle of the metaindex and index blocks as well as a magic number.
metaindex_handle: char[p]; // Block handle for metaindex
index_handle: char[q]; // Block handle for index
padding: char[40-p-q]; // zeroed bytes to make fixed length
// (40==2*BlockHandle::kMaxEncodedLength)
magic: fixed64; // == 0xdb4775248b80fb57 (little-endian)
"filter" Meta Block
-------------------
If a "FilterPolicy" was specified when the database was opened, a
filter block is stored in each table. The "metaindex" block contains
an entry that maps from "filter.<N>" to the BlockHandle for the filter
block where "<N>" is the string returned by the filter policy's
"Name()" method.
The filter block stores a sequence of filters, where filter i contains
the output of FilterPolicy::CreateFilter() on all keys that are stored
in a block whose file offset falls within the range
[ i*base ... (i+1)*base-1 ]
Currently, "base" is 2KB. So for example, if blocks X and Y start in
the range [ 0KB .. 2KB-1 ], all of the keys in X and Y will be
converted to a filter by calling FilterPolicy::CreateFilter(), and the
resulting filter will be stored as the first filter in the filter
block.
The filter block is formatted as follows:
[filter 0]
[filter 1]
[filter 2]
...
[filter N-1]
[offset of filter 0] : 4 bytes
[offset of filter 1] : 4 bytes
[offset of filter 2] : 4 bytes
...
[offset of filter N-1] : 4 bytes
[offset of beginning of offset array] : 4 bytes
lg(base) : 1 byte
The offset array at the end of the filter block allows efficient
mapping from a data block offset to the corresponding filter.
"stats" Meta Block
------------------
This meta block contains a bunch of stats. The key is the name
of the statistic. The value contains the statistic.
TODO(postrelease): record following stats.
data size
index size
key size (uncompressed)
value size (uncompressed)
number of entries
number of data blocks

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "helpers/memenv/memenv.h"
#include "leveldb/env.h"
#include "leveldb/status.h"
#include "port/port.h"
#include "util/mutexlock.h"
#include <map>
#include <string.h>
#include <string>
#include <vector>
namespace leveldb {
namespace {
class FileState {
public:
// FileStates are reference counted. The initial reference count is zero
// and the caller must call Ref() at least once.
FileState() : refs_(0), size_(0) {}
// Increase the reference count.
void Ref() {
MutexLock lock(&refs_mutex_);
++refs_;
}
// Decrease the reference count. Delete if this is the last reference.
void Unref() {
bool do_delete = false;
{
MutexLock lock(&refs_mutex_);
--refs_;
assert(refs_ >= 0);
if (refs_ <= 0) {
do_delete = true;
}
}
if (do_delete) {
delete this;
}
}
uint64_t Size() const { return size_; }
Status Read(uint64_t offset, size_t n, Slice* result, char* scratch) const {
if (offset > size_) {
return Status::IOError("Offset greater than file size.");
}
const uint64_t available = size_ - offset;
if (n > available) {
n = available;
}
if (n == 0) {
*result = Slice();
return Status::OK();
}
size_t block = offset / kBlockSize;
size_t block_offset = offset % kBlockSize;
if (n <= kBlockSize - block_offset) {
// The requested bytes are all in the first block.
*result = Slice(blocks_[block] + block_offset, n);
return Status::OK();
}
size_t bytes_to_copy = n;
char* dst = scratch;
while (bytes_to_copy > 0) {
size_t avail = kBlockSize - block_offset;
if (avail > bytes_to_copy) {
avail = bytes_to_copy;
}
memcpy(dst, blocks_[block] + block_offset, avail);
bytes_to_copy -= avail;
dst += avail;
block++;
block_offset = 0;
}
*result = Slice(scratch, n);
return Status::OK();
}
Status Append(const Slice& data) {
const char* src = data.data();
size_t src_len = data.size();
while (src_len > 0) {
size_t avail;
size_t offset = size_ % kBlockSize;
if (offset != 0) {
// There is some room in the last block.
avail = kBlockSize - offset;
} else {
// No room in the last block; push new one.
blocks_.push_back(new char[kBlockSize]);
avail = kBlockSize;
}
if (avail > src_len) {
avail = src_len;
}
memcpy(blocks_.back() + offset, src, avail);
src_len -= avail;
src += avail;
size_ += avail;
}
return Status::OK();
}
private:
// Private since only Unref() should be used to delete it.
~FileState() {
for (std::vector<char*>::iterator i = blocks_.begin(); i != blocks_.end();
++i) {
delete [] *i;
}
}
// No copying allowed.
FileState(const FileState&);
void operator=(const FileState&);
port::Mutex refs_mutex_;
int refs_; // Protected by refs_mutex_;
// The following fields are not protected by any mutex. They are only mutable
// while the file is being written, and concurrent access is not allowed
// to writable files.
std::vector<char*> blocks_;
uint64_t size_;
enum { kBlockSize = 8 * 1024 };
};
class SequentialFileImpl : public SequentialFile {
public:
explicit SequentialFileImpl(FileState* file) : file_(file), pos_(0) {
file_->Ref();
}
~SequentialFileImpl() {
file_->Unref();
}
virtual Status Read(size_t n, Slice* result, char* scratch) {
Status s = file_->Read(pos_, n, result, scratch);
if (s.ok()) {
pos_ += result->size();
}
return s;
}
virtual Status Skip(uint64_t n) {
if (pos_ > file_->Size()) {
return Status::IOError("pos_ > file_->Size()");
}
const size_t available = file_->Size() - pos_;
if (n > available) {
n = available;
}
pos_ += n;
return Status::OK();
}
private:
FileState* file_;
size_t pos_;
};
class RandomAccessFileImpl : public RandomAccessFile {
public:
explicit RandomAccessFileImpl(FileState* file) : file_(file) {
file_->Ref();
}
~RandomAccessFileImpl() {
file_->Unref();
}
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const {
return file_->Read(offset, n, result, scratch);
}
private:
FileState* file_;
};
class WritableFileImpl : public WritableFile {
public:
WritableFileImpl(FileState* file) : file_(file) {
file_->Ref();
}
~WritableFileImpl() {
file_->Unref();
}
virtual Status Append(const Slice& data) {
return file_->Append(data);
}
virtual Status Close() { return Status::OK(); }
virtual Status Flush() { return Status::OK(); }
virtual Status Sync() { return Status::OK(); }
private:
FileState* file_;
};
class NoOpLogger : public Logger {
public:
virtual void Logv(const char* format, va_list ap) { }
};
class InMemoryEnv : public EnvWrapper {
public:
explicit InMemoryEnv(Env* base_env) : EnvWrapper(base_env) { }
virtual ~InMemoryEnv() {
for (FileSystem::iterator i = file_map_.begin(); i != file_map_.end(); ++i){
i->second->Unref();
}
}
// Partial implementation of the Env interface.
virtual Status NewSequentialFile(const std::string& fname,
SequentialFile** result) {
MutexLock lock(&mutex_);
if (file_map_.find(fname) == file_map_.end()) {
*result = NULL;
return Status::IOError(fname, "File not found");
}
*result = new SequentialFileImpl(file_map_[fname]);
return Status::OK();
}
virtual Status NewRandomAccessFile(const std::string& fname,
RandomAccessFile** result) {
MutexLock lock(&mutex_);
if (file_map_.find(fname) == file_map_.end()) {
*result = NULL;
return Status::IOError(fname, "File not found");
}
*result = new RandomAccessFileImpl(file_map_[fname]);
return Status::OK();
}
virtual Status NewWritableFile(const std::string& fname,
WritableFile** result) {
MutexLock lock(&mutex_);
if (file_map_.find(fname) != file_map_.end()) {
DeleteFileInternal(fname);
}
FileState* file = new FileState();
file->Ref();
file_map_[fname] = file;
*result = new WritableFileImpl(file);
return Status::OK();
}
virtual bool FileExists(const std::string& fname) {
MutexLock lock(&mutex_);
return file_map_.find(fname) != file_map_.end();
}
virtual Status GetChildren(const std::string& dir,
std::vector<std::string>* result) {
MutexLock lock(&mutex_);
result->clear();
for (FileSystem::iterator i = file_map_.begin(); i != file_map_.end(); ++i){
const std::string& filename = i->first;
if (filename.size() >= dir.size() + 1 && filename[dir.size()] == '/' &&
Slice(filename).starts_with(Slice(dir))) {
result->push_back(filename.substr(dir.size() + 1));
}
}
return Status::OK();
}
void DeleteFileInternal(const std::string& fname) {
if (file_map_.find(fname) == file_map_.end()) {
return;
}
file_map_[fname]->Unref();
file_map_.erase(fname);
}
virtual Status DeleteFile(const std::string& fname) {
MutexLock lock(&mutex_);
if (file_map_.find(fname) == file_map_.end()) {
return Status::IOError(fname, "File not found");
}
DeleteFileInternal(fname);
return Status::OK();
}
virtual Status CreateDir(const std::string& dirname) {
return Status::OK();
}
virtual Status DeleteDir(const std::string& dirname) {
return Status::OK();
}
virtual Status GetFileSize(const std::string& fname, uint64_t* file_size) {
MutexLock lock(&mutex_);
if (file_map_.find(fname) == file_map_.end()) {
return Status::IOError(fname, "File not found");
}
*file_size = file_map_[fname]->Size();
return Status::OK();
}
virtual Status RenameFile(const std::string& src,
const std::string& target) {
MutexLock lock(&mutex_);
if (file_map_.find(src) == file_map_.end()) {
return Status::IOError(src, "File not found");
}
DeleteFileInternal(target);
file_map_[target] = file_map_[src];
file_map_.erase(src);
return Status::OK();
}
virtual Status LockFile(const std::string& fname, FileLock** lock) {
*lock = new FileLock;
return Status::OK();
}
virtual Status UnlockFile(FileLock* lock) {
delete lock;
return Status::OK();
}
virtual Status GetTestDirectory(std::string* path) {
*path = "/test";
return Status::OK();
}
virtual Status NewLogger(const std::string& fname, Logger** result) {
*result = new NoOpLogger;
return Status::OK();
}
private:
// Map from filenames to FileState objects, representing a simple file system.
typedef std::map<std::string, FileState*> FileSystem;
port::Mutex mutex_;
FileSystem file_map_; // Protected by mutex_.
};
} // namespace
Env* NewMemEnv(Env* base_env) {
return new InMemoryEnv(base_env);
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_HELPERS_MEMENV_MEMENV_H_
#define STORAGE_LEVELDB_HELPERS_MEMENV_MEMENV_H_
namespace leveldb {
class Env;
// Returns a new environment that stores its data in memory and delegates
// all non-file-storage tasks to base_env. The caller must delete the result
// when it is no longer needed.
// *base_env must remain live while the result is in use.
Env* NewMemEnv(Env* base_env);
} // namespace leveldb
#endif // STORAGE_LEVELDB_HELPERS_MEMENV_MEMENV_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "helpers/memenv/memenv.h"
#include "db/db_impl.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "util/testharness.h"
#include <string>
#include <vector>
namespace leveldb {
class MemEnvTest {
public:
Env* env_;
MemEnvTest()
: env_(NewMemEnv(Env::Default())) {
}
~MemEnvTest() {
delete env_;
}
};
TEST(MemEnvTest, Basics) {
uint64_t file_size;
WritableFile* writable_file;
std::vector<std::string> children;
ASSERT_OK(env_->CreateDir("/dir"));
// Check that the directory is empty.
ASSERT_TRUE(!env_->FileExists("/dir/non_existent"));
ASSERT_TRUE(!env_->GetFileSize("/dir/non_existent", &file_size).ok());
ASSERT_OK(env_->GetChildren("/dir", &children));
ASSERT_EQ(0, children.size());
// Create a file.
ASSERT_OK(env_->NewWritableFile("/dir/f", &writable_file));
delete writable_file;
// Check that the file exists.
ASSERT_TRUE(env_->FileExists("/dir/f"));
ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
ASSERT_EQ(0, file_size);
ASSERT_OK(env_->GetChildren("/dir", &children));
ASSERT_EQ(1, children.size());
ASSERT_EQ("f", children[0]);
// Write to the file.
ASSERT_OK(env_->NewWritableFile("/dir/f", &writable_file));
ASSERT_OK(writable_file->Append("abc"));
delete writable_file;
// Check for expected size.
ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
ASSERT_EQ(3, file_size);
// Check that renaming works.
ASSERT_TRUE(!env_->RenameFile("/dir/non_existent", "/dir/g").ok());
ASSERT_OK(env_->RenameFile("/dir/f", "/dir/g"));
ASSERT_TRUE(!env_->FileExists("/dir/f"));
ASSERT_TRUE(env_->FileExists("/dir/g"));
ASSERT_OK(env_->GetFileSize("/dir/g", &file_size));
ASSERT_EQ(3, file_size);
// Check that opening non-existent file fails.
SequentialFile* seq_file;
RandomAccessFile* rand_file;
ASSERT_TRUE(!env_->NewSequentialFile("/dir/non_existent", &seq_file).ok());
ASSERT_TRUE(!seq_file);
ASSERT_TRUE(!env_->NewRandomAccessFile("/dir/non_existent", &rand_file).ok());
ASSERT_TRUE(!rand_file);
// Check that deleting works.
ASSERT_TRUE(!env_->DeleteFile("/dir/non_existent").ok());
ASSERT_OK(env_->DeleteFile("/dir/g"));
ASSERT_TRUE(!env_->FileExists("/dir/g"));
ASSERT_OK(env_->GetChildren("/dir", &children));
ASSERT_EQ(0, children.size());
ASSERT_OK(env_->DeleteDir("/dir"));
}
TEST(MemEnvTest, ReadWrite) {
WritableFile* writable_file;
SequentialFile* seq_file;
RandomAccessFile* rand_file;
Slice result;
char scratch[100];
ASSERT_OK(env_->CreateDir("/dir"));
ASSERT_OK(env_->NewWritableFile("/dir/f", &writable_file));
ASSERT_OK(writable_file->Append("hello "));
ASSERT_OK(writable_file->Append("world"));
delete writable_file;
// Read sequentially.
ASSERT_OK(env_->NewSequentialFile("/dir/f", &seq_file));
ASSERT_OK(seq_file->Read(5, &result, scratch)); // Read "hello".
ASSERT_EQ(0, result.compare("hello"));
ASSERT_OK(seq_file->Skip(1));
ASSERT_OK(seq_file->Read(1000, &result, scratch)); // Read "world".
ASSERT_EQ(0, result.compare("world"));
ASSERT_OK(seq_file->Read(1000, &result, scratch)); // Try reading past EOF.
ASSERT_EQ(0, result.size());
ASSERT_OK(seq_file->Skip(100)); // Try to skip past end of file.
ASSERT_OK(seq_file->Read(1000, &result, scratch));
ASSERT_EQ(0, result.size());
delete seq_file;
// Random reads.
ASSERT_OK(env_->NewRandomAccessFile("/dir/f", &rand_file));
ASSERT_OK(rand_file->Read(6, 5, &result, scratch)); // Read "world".
ASSERT_EQ(0, result.compare("world"));
ASSERT_OK(rand_file->Read(0, 5, &result, scratch)); // Read "hello".
ASSERT_EQ(0, result.compare("hello"));
ASSERT_OK(rand_file->Read(10, 100, &result, scratch)); // Read "d".
ASSERT_EQ(0, result.compare("d"));
// Too high offset.
ASSERT_TRUE(!rand_file->Read(1000, 5, &result, scratch).ok());
delete rand_file;
}
TEST(MemEnvTest, Locks) {
FileLock* lock;
// These are no-ops, but we test they return success.
ASSERT_OK(env_->LockFile("some file", &lock));
ASSERT_OK(env_->UnlockFile(lock));
}
TEST(MemEnvTest, Misc) {
std::string test_dir;
ASSERT_OK(env_->GetTestDirectory(&test_dir));
ASSERT_TRUE(!test_dir.empty());
WritableFile* writable_file;
ASSERT_OK(env_->NewWritableFile("/a/b", &writable_file));
// These are no-ops, but we test they return success.
ASSERT_OK(writable_file->Sync());
ASSERT_OK(writable_file->Flush());
ASSERT_OK(writable_file->Close());
delete writable_file;
}
TEST(MemEnvTest, LargeWrite) {
const size_t kWriteSize = 300 * 1024;
char* scratch = new char[kWriteSize * 2];
std::string write_data;
for (size_t i = 0; i < kWriteSize; ++i) {
write_data.append(1, static_cast<char>(i));
}
WritableFile* writable_file;
ASSERT_OK(env_->NewWritableFile("/dir/f", &writable_file));
ASSERT_OK(writable_file->Append("foo"));
ASSERT_OK(writable_file->Append(write_data));
delete writable_file;
SequentialFile* seq_file;
Slice result;
ASSERT_OK(env_->NewSequentialFile("/dir/f", &seq_file));
ASSERT_OK(seq_file->Read(3, &result, scratch)); // Read "foo".
ASSERT_EQ(0, result.compare("foo"));
size_t read = 0;
std::string read_data;
while (read < kWriteSize) {
ASSERT_OK(seq_file->Read(kWriteSize - read, &result, scratch));
read_data.append(result.data(), result.size());
read += result.size();
}
ASSERT_TRUE(write_data == read_data);
delete seq_file;
delete [] scratch;
}
TEST(MemEnvTest, DBTest) {
Options options;
options.create_if_missing = true;
options.env = env_;
DB* db;
const Slice keys[] = {Slice("aaa"), Slice("bbb"), Slice("ccc")};
const Slice vals[] = {Slice("foo"), Slice("bar"), Slice("baz")};
ASSERT_OK(DB::Open(options, "/dir/db", &db));
for (size_t i = 0; i < 3; ++i) {
ASSERT_OK(db->Put(WriteOptions(), keys[i], vals[i]));
}
for (size_t i = 0; i < 3; ++i) {
std::string res;
ASSERT_OK(db->Get(ReadOptions(), keys[i], &res));
ASSERT_TRUE(res == vals[i]);
}
Iterator* iterator = db->NewIterator(ReadOptions());
iterator->SeekToFirst();
for (size_t i = 0; i < 3; ++i) {
ASSERT_TRUE(iterator->Valid());
ASSERT_TRUE(keys[i] == iterator->key());
ASSERT_TRUE(vals[i] == iterator->value());
iterator->Next();
}
ASSERT_TRUE(!iterator->Valid());
delete iterator;
DBImpl* dbi = reinterpret_cast<DBImpl*>(db);
ASSERT_OK(dbi->TEST_CompactMemTable());
for (size_t i = 0; i < 3; ++i) {
std::string res;
ASSERT_OK(db->Get(ReadOptions(), keys[i], &res));
ASSERT_TRUE(res == vals[i]);
}
delete db;
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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/* Copyright (c) 2011 The LevelDB Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file. See the AUTHORS file for names of contributors.
C bindings for leveldb. May be useful as a stable ABI that can be
used by programs that keep leveldb in a shared library, or for
a JNI api.
Does not support:
. getters for the option types
. custom comparators that implement key shortening
. capturing post-write-snapshot
. custom iter, db, env, cache implementations using just the C bindings
Some conventions:
(1) We expose just opaque struct pointers and functions to clients.
This allows us to change internal representations without having to
recompile clients.
(2) For simplicity, there is no equivalent to the Slice type. Instead,
the caller has to pass the pointer and length as separate
arguments.
(3) Errors are represented by a null-terminated c string. NULL
means no error. All operations that can raise an error are passed
a "char** errptr" as the last argument. One of the following must
be true on entry:
*errptr == NULL
*errptr points to a malloc()ed null-terminated error message
(On Windows, *errptr must have been malloc()-ed by this library.)
On success, a leveldb routine leaves *errptr unchanged.
On failure, leveldb frees the old value of *errptr and
set *errptr to a malloc()ed error message.
(4) Bools have the type unsigned char (0 == false; rest == true)
(5) All of the pointer arguments must be non-NULL.
*/
#ifndef STORAGE_LEVELDB_INCLUDE_C_H_
#define STORAGE_LEVELDB_INCLUDE_C_H_
#ifdef __cplusplus
extern "C" {
#endif
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
/* Exported types */
typedef struct leveldb_t leveldb_t;
typedef struct leveldb_cache_t leveldb_cache_t;
typedef struct leveldb_comparator_t leveldb_comparator_t;
typedef struct leveldb_env_t leveldb_env_t;
typedef struct leveldb_filelock_t leveldb_filelock_t;
typedef struct leveldb_filterpolicy_t leveldb_filterpolicy_t;
typedef struct leveldb_iterator_t leveldb_iterator_t;
typedef struct leveldb_logger_t leveldb_logger_t;
typedef struct leveldb_options_t leveldb_options_t;
typedef struct leveldb_randomfile_t leveldb_randomfile_t;
typedef struct leveldb_readoptions_t leveldb_readoptions_t;
typedef struct leveldb_seqfile_t leveldb_seqfile_t;
typedef struct leveldb_snapshot_t leveldb_snapshot_t;
typedef struct leveldb_writablefile_t leveldb_writablefile_t;
typedef struct leveldb_writebatch_t leveldb_writebatch_t;
typedef struct leveldb_writeoptions_t leveldb_writeoptions_t;
/* DB operations */
extern leveldb_t* leveldb_open(
const leveldb_options_t* options,
const char* name,
char** errptr);
extern void leveldb_close(leveldb_t* db);
extern void leveldb_put(
leveldb_t* db,
const leveldb_writeoptions_t* options,
const char* key, size_t keylen,
const char* val, size_t vallen,
char** errptr);
extern void leveldb_delete(
leveldb_t* db,
const leveldb_writeoptions_t* options,
const char* key, size_t keylen,
char** errptr);
extern void leveldb_write(
leveldb_t* db,
const leveldb_writeoptions_t* options,
leveldb_writebatch_t* batch,
char** errptr);
/* Returns NULL if not found. A malloc()ed array otherwise.
Stores the length of the array in *vallen. */
extern char* leveldb_get(
leveldb_t* db,
const leveldb_readoptions_t* options,
const char* key, size_t keylen,
size_t* vallen,
char** errptr);
extern leveldb_iterator_t* leveldb_create_iterator(
leveldb_t* db,
const leveldb_readoptions_t* options);
extern const leveldb_snapshot_t* leveldb_create_snapshot(
leveldb_t* db);
extern void leveldb_release_snapshot(
leveldb_t* db,
const leveldb_snapshot_t* snapshot);
/* Returns NULL if property name is unknown.
Else returns a pointer to a malloc()-ed null-terminated value. */
extern char* leveldb_property_value(
leveldb_t* db,
const char* propname);
extern void leveldb_approximate_sizes(
leveldb_t* db,
int num_ranges,
const char* const* range_start_key, const size_t* range_start_key_len,
const char* const* range_limit_key, const size_t* range_limit_key_len,
uint64_t* sizes);
extern void leveldb_compact_range(
leveldb_t* db,
const char* start_key, size_t start_key_len,
const char* limit_key, size_t limit_key_len);
/* Management operations */
extern void leveldb_destroy_db(
const leveldb_options_t* options,
const char* name,
char** errptr);
extern void leveldb_repair_db(
const leveldb_options_t* options,
const char* name,
char** errptr);
/* Iterator */
extern void leveldb_iter_destroy(leveldb_iterator_t*);
extern unsigned char leveldb_iter_valid(const leveldb_iterator_t*);
extern void leveldb_iter_seek_to_first(leveldb_iterator_t*);
extern void leveldb_iter_seek_to_last(leveldb_iterator_t*);
extern void leveldb_iter_seek(leveldb_iterator_t*, const char* k, size_t klen);
extern void leveldb_iter_next(leveldb_iterator_t*);
extern void leveldb_iter_prev(leveldb_iterator_t*);
extern const char* leveldb_iter_key(const leveldb_iterator_t*, size_t* klen);
extern const char* leveldb_iter_value(const leveldb_iterator_t*, size_t* vlen);
extern void leveldb_iter_get_error(const leveldb_iterator_t*, char** errptr);
/* Write batch */
extern leveldb_writebatch_t* leveldb_writebatch_create();
extern void leveldb_writebatch_destroy(leveldb_writebatch_t*);
extern void leveldb_writebatch_clear(leveldb_writebatch_t*);
extern void leveldb_writebatch_put(
leveldb_writebatch_t*,
const char* key, size_t klen,
const char* val, size_t vlen);
extern void leveldb_writebatch_delete(
leveldb_writebatch_t*,
const char* key, size_t klen);
extern void leveldb_writebatch_iterate(
leveldb_writebatch_t*,
void* state,
void (*put)(void*, const char* k, size_t klen, const char* v, size_t vlen),
void (*deleted)(void*, const char* k, size_t klen));
/* Options */
extern leveldb_options_t* leveldb_options_create();
extern void leveldb_options_destroy(leveldb_options_t*);
extern void leveldb_options_set_comparator(
leveldb_options_t*,
leveldb_comparator_t*);
extern void leveldb_options_set_filter_policy(
leveldb_options_t*,
leveldb_filterpolicy_t*);
extern void leveldb_options_set_create_if_missing(
leveldb_options_t*, unsigned char);
extern void leveldb_options_set_error_if_exists(
leveldb_options_t*, unsigned char);
extern void leveldb_options_set_paranoid_checks(
leveldb_options_t*, unsigned char);
extern void leveldb_options_set_env(leveldb_options_t*, leveldb_env_t*);
extern void leveldb_options_set_info_log(leveldb_options_t*, leveldb_logger_t*);
extern void leveldb_options_set_write_buffer_size(leveldb_options_t*, size_t);
extern void leveldb_options_set_max_open_files(leveldb_options_t*, int);
extern void leveldb_options_set_cache(leveldb_options_t*, leveldb_cache_t*);
extern void leveldb_options_set_block_size(leveldb_options_t*, size_t);
extern void leveldb_options_set_block_restart_interval(leveldb_options_t*, int);
enum {
leveldb_no_compression = 0,
leveldb_snappy_compression = 1
};
extern void leveldb_options_set_compression(leveldb_options_t*, int);
/* Comparator */
extern leveldb_comparator_t* leveldb_comparator_create(
void* state,
void (*destructor)(void*),
int (*compare)(
void*,
const char* a, size_t alen,
const char* b, size_t blen),
const char* (*name)(void*));
extern void leveldb_comparator_destroy(leveldb_comparator_t*);
/* Filter policy */
extern leveldb_filterpolicy_t* leveldb_filterpolicy_create(
void* state,
void (*destructor)(void*),
char* (*create_filter)(
void*,
const char* const* key_array, const size_t* key_length_array,
int num_keys,
size_t* filter_length),
unsigned char (*key_may_match)(
void*,
const char* key, size_t length,
const char* filter, size_t filter_length),
const char* (*name)(void*));
extern void leveldb_filterpolicy_destroy(leveldb_filterpolicy_t*);
extern leveldb_filterpolicy_t* leveldb_filterpolicy_create_bloom(
int bits_per_key);
/* Read options */
extern leveldb_readoptions_t* leveldb_readoptions_create();
extern void leveldb_readoptions_destroy(leveldb_readoptions_t*);
extern void leveldb_readoptions_set_verify_checksums(
leveldb_readoptions_t*,
unsigned char);
extern void leveldb_readoptions_set_fill_cache(
leveldb_readoptions_t*, unsigned char);
extern void leveldb_readoptions_set_snapshot(
leveldb_readoptions_t*,
const leveldb_snapshot_t*);
/* Write options */
extern leveldb_writeoptions_t* leveldb_writeoptions_create();
extern void leveldb_writeoptions_destroy(leveldb_writeoptions_t*);
extern void leveldb_writeoptions_set_sync(
leveldb_writeoptions_t*, unsigned char);
/* Cache */
extern leveldb_cache_t* leveldb_cache_create_lru(size_t capacity);
extern void leveldb_cache_destroy(leveldb_cache_t* cache);
/* Env */
extern leveldb_env_t* leveldb_create_default_env();
extern void leveldb_env_destroy(leveldb_env_t*);
/* Utility */
/* Calls free(ptr).
REQUIRES: ptr was malloc()-ed and returned by one of the routines
in this file. Note that in certain cases (typically on Windows), you
may need to call this routine instead of free(ptr) to dispose of
malloc()-ed memory returned by this library. */
extern void leveldb_free(void* ptr);
/* Return the major version number for this release. */
extern int leveldb_major_version();
/* Return the minor version number for this release. */
extern int leveldb_minor_version();
#ifdef __cplusplus
} /* end extern "C" */
#endif
#endif /* STORAGE_LEVELDB_INCLUDE_C_H_ */

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// A Cache is an interface that maps keys to values. It has internal
// synchronization and may be safely accessed concurrently from
// multiple threads. It may automatically evict entries to make room
// for new entries. Values have a specified charge against the cache
// capacity. For example, a cache where the values are variable
// length strings, may use the length of the string as the charge for
// the string.
//
// A builtin cache implementation with a least-recently-used eviction
// policy is provided. Clients may use their own implementations if
// they want something more sophisticated (like scan-resistance, a
// custom eviction policy, variable cache sizing, etc.)
#ifndef STORAGE_LEVELDB_INCLUDE_CACHE_H_
#define STORAGE_LEVELDB_INCLUDE_CACHE_H_
#include <stdint.h>
#include "leveldb/slice.h"
namespace leveldb {
class Cache;
// Create a new cache with a fixed size capacity. This implementation
// of Cache uses a least-recently-used eviction policy.
extern Cache* NewLRUCache(size_t capacity);
class Cache {
public:
Cache() { }
// Destroys all existing entries by calling the "deleter"
// function that was passed to the constructor.
virtual ~Cache();
// Opaque handle to an entry stored in the cache.
struct Handle { };
// Insert a mapping from key->value into the cache and assign it
// the specified charge against the total cache capacity.
//
// Returns a handle that corresponds to the mapping. The caller
// must call this->Release(handle) when the returned mapping is no
// longer needed.
//
// When the inserted entry is no longer needed, the key and
// value will be passed to "deleter".
virtual Handle* Insert(const Slice& key, void* value, size_t charge,
void (*deleter)(const Slice& key, void* value)) = 0;
// If the cache has no mapping for "key", returns NULL.
//
// Else return a handle that corresponds to the mapping. The caller
// must call this->Release(handle) when the returned mapping is no
// longer needed.
virtual Handle* Lookup(const Slice& key) = 0;
// Release a mapping returned by a previous Lookup().
// REQUIRES: handle must not have been released yet.
// REQUIRES: handle must have been returned by a method on *this.
virtual void Release(Handle* handle) = 0;
// Return the value encapsulated in a handle returned by a
// successful Lookup().
// REQUIRES: handle must not have been released yet.
// REQUIRES: handle must have been returned by a method on *this.
virtual void* Value(Handle* handle) = 0;
// If the cache contains entry for key, erase it. Note that the
// underlying entry will be kept around until all existing handles
// to it have been released.
virtual void Erase(const Slice& key) = 0;
// Return a new numeric id. May be used by multiple clients who are
// sharing the same cache to partition the key space. Typically the
// client will allocate a new id at startup and prepend the id to
// its cache keys.
virtual uint64_t NewId() = 0;
private:
void LRU_Remove(Handle* e);
void LRU_Append(Handle* e);
void Unref(Handle* e);
struct Rep;
Rep* rep_;
// No copying allowed
Cache(const Cache&);
void operator=(const Cache&);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_UTIL_CACHE_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_INCLUDE_COMPARATOR_H_
#define STORAGE_LEVELDB_INCLUDE_COMPARATOR_H_
#include <string>
namespace leveldb {
class Slice;
// A Comparator object provides a total order across slices that are
// used as keys in an sstable or a database. A Comparator implementation
// must be thread-safe since leveldb may invoke its methods concurrently
// from multiple threads.
class Comparator {
public:
virtual ~Comparator();
// Three-way comparison. Returns value:
// < 0 iff "a" < "b",
// == 0 iff "a" == "b",
// > 0 iff "a" > "b"
virtual int Compare(const Slice& a, const Slice& b) const = 0;
// The name of the comparator. Used to check for comparator
// mismatches (i.e., a DB created with one comparator is
// accessed using a different comparator.
//
// The client of this package should switch to a new name whenever
// the comparator implementation changes in a way that will cause
// the relative ordering of any two keys to change.
//
// Names starting with "leveldb." are reserved and should not be used
// by any clients of this package.
virtual const char* Name() const = 0;
// Advanced functions: these are used to reduce the space requirements
// for internal data structures like index blocks.
// If *start < limit, changes *start to a short string in [start,limit).
// Simple comparator implementations may return with *start unchanged,
// i.e., an implementation of this method that does nothing is correct.
virtual void FindShortestSeparator(
std::string* start,
const Slice& limit) const = 0;
// Changes *key to a short string >= *key.
// Simple comparator implementations may return with *key unchanged,
// i.e., an implementation of this method that does nothing is correct.
virtual void FindShortSuccessor(std::string* key) const = 0;
};
// Return a builtin comparator that uses lexicographic byte-wise
// ordering. The result remains the property of this module and
// must not be deleted.
extern const Comparator* BytewiseComparator();
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_COMPARATOR_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_INCLUDE_DB_H_
#define STORAGE_LEVELDB_INCLUDE_DB_H_
#include <stdint.h>
#include <stdio.h>
#include "leveldb/iterator.h"
#include "leveldb/options.h"
namespace leveldb {
// Update Makefile if you change these
static const int kMajorVersion = 1;
static const int kMinorVersion = 7;
struct Options;
struct ReadOptions;
struct WriteOptions;
class WriteBatch;
// Abstract handle to particular state of a DB.
// A Snapshot is an immutable object and can therefore be safely
// accessed from multiple threads without any external synchronization.
class Snapshot {
protected:
virtual ~Snapshot();
};
// A range of keys
struct Range {
Slice start; // Included in the range
Slice limit; // Not included in the range
Range() { }
Range(const Slice& s, const Slice& l) : start(s), limit(l) { }
};
// A DB is a persistent ordered map from keys to values.
// A DB is safe for concurrent access from multiple threads without
// any external synchronization.
class DB {
public:
// Open the database with the specified "name".
// Stores a pointer to a heap-allocated database in *dbptr and returns
// OK on success.
// Stores NULL in *dbptr and returns a non-OK status on error.
// Caller should delete *dbptr when it is no longer needed.
static Status Open(const Options& options,
const std::string& name,
DB** dbptr);
DB() { }
virtual ~DB();
// Set the database entry for "key" to "value". Returns OK on success,
// and a non-OK status on error.
// Note: consider setting options.sync = true.
virtual Status Put(const WriteOptions& options,
const Slice& key,
const Slice& value) = 0;
// Remove the database entry (if any) for "key". Returns OK on
// success, and a non-OK status on error. It is not an error if "key"
// did not exist in the database.
// Note: consider setting options.sync = true.
virtual Status Delete(const WriteOptions& options, const Slice& key) = 0;
// Apply the specified updates to the database.
// Returns OK on success, non-OK on failure.
// Note: consider setting options.sync = true.
virtual Status Write(const WriteOptions& options, WriteBatch* updates) = 0;
// If the database contains an entry for "key" store the
// corresponding value in *value and return OK.
//
// If there is no entry for "key" leave *value unchanged and return
// a status for which Status::IsNotFound() returns true.
//
// May return some other Status on an error.
virtual Status Get(const ReadOptions& options,
const Slice& key, std::string* value) = 0;
// Return a heap-allocated iterator over the contents of the database.
// The result of NewIterator() is initially invalid (caller must
// call one of the Seek methods on the iterator before using it).
//
// Caller should delete the iterator when it is no longer needed.
// The returned iterator should be deleted before this db is deleted.
virtual Iterator* NewIterator(const ReadOptions& options) = 0;
// Return a handle to the current DB state. Iterators created with
// this handle will all observe a stable snapshot of the current DB
// state. The caller must call ReleaseSnapshot(result) when the
// snapshot is no longer needed.
virtual const Snapshot* GetSnapshot() = 0;
// Release a previously acquired snapshot. The caller must not
// use "snapshot" after this call.
virtual void ReleaseSnapshot(const Snapshot* snapshot) = 0;
// DB implementations can export properties about their state
// via this method. If "property" is a valid property understood by this
// DB implementation, fills "*value" with its current value and returns
// true. Otherwise returns false.
//
//
// Valid property names include:
//
// "leveldb.num-files-at-level<N>" - return the number of files at level <N>,
// where <N> is an ASCII representation of a level number (e.g. "0").
// "leveldb.stats" - returns a multi-line string that describes statistics
// about the internal operation of the DB.
// "leveldb.sstables" - returns a multi-line string that describes all
// of the sstables that make up the db contents.
virtual bool GetProperty(const Slice& property, std::string* value) = 0;
// For each i in [0,n-1], store in "sizes[i]", the approximate
// file system space used by keys in "[range[i].start .. range[i].limit)".
//
// Note that the returned sizes measure file system space usage, so
// if the user data compresses by a factor of ten, the returned
// sizes will be one-tenth the size of the corresponding user data size.
//
// The results may not include the sizes of recently written data.
virtual void GetApproximateSizes(const Range* range, int n,
uint64_t* sizes) = 0;
// Compact the underlying storage for the key range [*begin,*end].
// In particular, deleted and overwritten versions are discarded,
// and the data is rearranged to reduce the cost of operations
// needed to access the data. This operation should typically only
// be invoked by users who understand the underlying implementation.
//
// begin==NULL is treated as a key before all keys in the database.
// end==NULL is treated as a key after all keys in the database.
// Therefore the following call will compact the entire database:
// db->CompactRange(NULL, NULL);
virtual void CompactRange(const Slice* begin, const Slice* end) = 0;
private:
// No copying allowed
DB(const DB&);
void operator=(const DB&);
};
// Destroy the contents of the specified database.
// Be very careful using this method.
Status DestroyDB(const std::string& name, const Options& options);
// If a DB cannot be opened, you may attempt to call this method to
// resurrect as much of the contents of the database as possible.
// Some data may be lost, so be careful when calling this function
// on a database that contains important information.
Status RepairDB(const std::string& dbname, const Options& options);
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_DB_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// An Env is an interface used by the leveldb implementation to access
// operating system functionality like the filesystem etc. Callers
// may wish to provide a custom Env object when opening a database to
// get fine gain control; e.g., to rate limit file system operations.
//
// All Env implementations are safe for concurrent access from
// multiple threads without any external synchronization.
#ifndef STORAGE_LEVELDB_INCLUDE_ENV_H_
#define STORAGE_LEVELDB_INCLUDE_ENV_H_
#include <cstdarg>
#include <string>
#include <vector>
#include <stdint.h>
#include "leveldb/status.h"
namespace leveldb {
class FileLock;
class Logger;
class RandomAccessFile;
class SequentialFile;
class Slice;
class WritableFile;
class Env {
public:
Env() { }
virtual ~Env();
// Return a default environment suitable for the current operating
// system. Sophisticated users may wish to provide their own Env
// implementation instead of relying on this default environment.
//
// The result of Default() belongs to leveldb and must never be deleted.
static Env* Default();
// Create a brand new sequentially-readable file with the specified name.
// On success, stores a pointer to the new file in *result and returns OK.
// On failure stores NULL in *result and returns non-OK. If the file does
// not exist, returns a non-OK status.
//
// The returned file will only be accessed by one thread at a time.
virtual Status NewSequentialFile(const std::string& fname,
SequentialFile** result) = 0;
// Create a brand new random access read-only file with the
// specified name. On success, stores a pointer to the new file in
// *result and returns OK. On failure stores NULL in *result and
// returns non-OK. If the file does not exist, returns a non-OK
// status.
//
// The returned file may be concurrently accessed by multiple threads.
virtual Status NewRandomAccessFile(const std::string& fname,
RandomAccessFile** result) = 0;
// Create an object that writes to a new file with the specified
// name. Deletes any existing file with the same name and creates a
// new file. On success, stores a pointer to the new file in
// *result and returns OK. On failure stores NULL in *result and
// returns non-OK.
//
// The returned file will only be accessed by one thread at a time.
virtual Status NewWritableFile(const std::string& fname,
WritableFile** result) = 0;
// Returns true iff the named file exists.
virtual bool FileExists(const std::string& fname) = 0;
// Store in *result the names of the children of the specified directory.
// The names are relative to "dir".
// Original contents of *results are dropped.
virtual Status GetChildren(const std::string& dir,
std::vector<std::string>* result) = 0;
// Delete the named file.
virtual Status DeleteFile(const std::string& fname) = 0;
// Create the specified directory.
virtual Status CreateDir(const std::string& dirname) = 0;
// Delete the specified directory.
virtual Status DeleteDir(const std::string& dirname) = 0;
// Store the size of fname in *file_size.
virtual Status GetFileSize(const std::string& fname, uint64_t* file_size) = 0;
// Rename file src to target.
virtual Status RenameFile(const std::string& src,
const std::string& target) = 0;
// Lock the specified file. Used to prevent concurrent access to
// the same db by multiple processes. On failure, stores NULL in
// *lock and returns non-OK.
//
// On success, stores a pointer to the object that represents the
// acquired lock in *lock and returns OK. The caller should call
// UnlockFile(*lock) to release the lock. If the process exits,
// the lock will be automatically released.
//
// If somebody else already holds the lock, finishes immediately
// with a failure. I.e., this call does not wait for existing locks
// to go away.
//
// May create the named file if it does not already exist.
virtual Status LockFile(const std::string& fname, FileLock** lock) = 0;
// Release the lock acquired by a previous successful call to LockFile.
// REQUIRES: lock was returned by a successful LockFile() call
// REQUIRES: lock has not already been unlocked.
virtual Status UnlockFile(FileLock* lock) = 0;
// Arrange to run "(*function)(arg)" once in a background thread.
//
// "function" may run in an unspecified thread. Multiple functions
// added to the same Env may run concurrently in different threads.
// I.e., the caller may not assume that background work items are
// serialized.
virtual void Schedule(
void (*function)(void* arg),
void* arg) = 0;
// Start a new thread, invoking "function(arg)" within the new thread.
// When "function(arg)" returns, the thread will be destroyed.
virtual void StartThread(void (*function)(void* arg), void* arg) = 0;
// *path is set to a temporary directory that can be used for testing. It may
// or many not have just been created. The directory may or may not differ
// between runs of the same process, but subsequent calls will return the
// same directory.
virtual Status GetTestDirectory(std::string* path) = 0;
// Create and return a log file for storing informational messages.
virtual Status NewLogger(const std::string& fname, Logger** result) = 0;
// Returns the number of micro-seconds since some fixed point in time. Only
// useful for computing deltas of time.
virtual uint64_t NowMicros() = 0;
// Sleep/delay the thread for the perscribed number of micro-seconds.
virtual void SleepForMicroseconds(int micros) = 0;
private:
// No copying allowed
Env(const Env&);
void operator=(const Env&);
};
// A file abstraction for reading sequentially through a file
class SequentialFile {
public:
SequentialFile() { }
virtual ~SequentialFile();
// Read up to "n" bytes from the file. "scratch[0..n-1]" may be
// written by this routine. Sets "*result" to the data that was
// read (including if fewer than "n" bytes were successfully read).
// May set "*result" to point at data in "scratch[0..n-1]", so
// "scratch[0..n-1]" must be live when "*result" is used.
// If an error was encountered, returns a non-OK status.
//
// REQUIRES: External synchronization
virtual Status Read(size_t n, Slice* result, char* scratch) = 0;
// Skip "n" bytes from the file. This is guaranteed to be no
// slower that reading the same data, but may be faster.
//
// If end of file is reached, skipping will stop at the end of the
// file, and Skip will return OK.
//
// REQUIRES: External synchronization
virtual Status Skip(uint64_t n) = 0;
private:
// No copying allowed
SequentialFile(const SequentialFile&);
void operator=(const SequentialFile&);
};
// A file abstraction for randomly reading the contents of a file.
class RandomAccessFile {
public:
RandomAccessFile() { }
virtual ~RandomAccessFile();
// Read up to "n" bytes from the file starting at "offset".
// "scratch[0..n-1]" may be written by this routine. Sets "*result"
// to the data that was read (including if fewer than "n" bytes were
// successfully read). May set "*result" to point at data in
// "scratch[0..n-1]", so "scratch[0..n-1]" must be live when
// "*result" is used. If an error was encountered, returns a non-OK
// status.
//
// Safe for concurrent use by multiple threads.
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const = 0;
private:
// No copying allowed
RandomAccessFile(const RandomAccessFile&);
void operator=(const RandomAccessFile&);
};
// A file abstraction for sequential writing. The implementation
// must provide buffering since callers may append small fragments
// at a time to the file.
class WritableFile {
public:
WritableFile() { }
virtual ~WritableFile();
virtual Status Append(const Slice& data) = 0;
virtual Status Close() = 0;
virtual Status Flush() = 0;
virtual Status Sync() = 0;
private:
// No copying allowed
WritableFile(const WritableFile&);
void operator=(const WritableFile&);
};
// An interface for writing log messages.
class Logger {
public:
Logger() { }
virtual ~Logger();
// Write an entry to the log file with the specified format.
virtual void Logv(const char* format, va_list ap) = 0;
private:
// No copying allowed
Logger(const Logger&);
void operator=(const Logger&);
};
// Identifies a locked file.
class FileLock {
public:
FileLock() { }
virtual ~FileLock();
private:
// No copying allowed
FileLock(const FileLock&);
void operator=(const FileLock&);
};
// Log the specified data to *info_log if info_log is non-NULL.
extern void Log(Logger* info_log, const char* format, ...)
# if defined(__GNUC__) || defined(__clang__)
__attribute__((__format__ (__printf__, 2, 3)))
# endif
;
// A utility routine: write "data" to the named file.
extern Status WriteStringToFile(Env* env, const Slice& data,
const std::string& fname);
// A utility routine: read contents of named file into *data
extern Status ReadFileToString(Env* env, const std::string& fname,
std::string* data);
// An implementation of Env that forwards all calls to another Env.
// May be useful to clients who wish to override just part of the
// functionality of another Env.
class EnvWrapper : public Env {
public:
// Initialize an EnvWrapper that delegates all calls to *t
explicit EnvWrapper(Env* t) : target_(t) { }
virtual ~EnvWrapper();
// Return the target to which this Env forwards all calls
Env* target() const { return target_; }
// The following text is boilerplate that forwards all methods to target()
Status NewSequentialFile(const std::string& f, SequentialFile** r) {
return target_->NewSequentialFile(f, r);
}
Status NewRandomAccessFile(const std::string& f, RandomAccessFile** r) {
return target_->NewRandomAccessFile(f, r);
}
Status NewWritableFile(const std::string& f, WritableFile** r) {
return target_->NewWritableFile(f, r);
}
bool FileExists(const std::string& f) { return target_->FileExists(f); }
Status GetChildren(const std::string& dir, std::vector<std::string>* r) {
return target_->GetChildren(dir, r);
}
Status DeleteFile(const std::string& f) { return target_->DeleteFile(f); }
Status CreateDir(const std::string& d) { return target_->CreateDir(d); }
Status DeleteDir(const std::string& d) { return target_->DeleteDir(d); }
Status GetFileSize(const std::string& f, uint64_t* s) {
return target_->GetFileSize(f, s);
}
Status RenameFile(const std::string& s, const std::string& t) {
return target_->RenameFile(s, t);
}
Status LockFile(const std::string& f, FileLock** l) {
return target_->LockFile(f, l);
}
Status UnlockFile(FileLock* l) { return target_->UnlockFile(l); }
void Schedule(void (*f)(void*), void* a) {
return target_->Schedule(f, a);
}
void StartThread(void (*f)(void*), void* a) {
return target_->StartThread(f, a);
}
virtual Status GetTestDirectory(std::string* path) {
return target_->GetTestDirectory(path);
}
virtual Status NewLogger(const std::string& fname, Logger** result) {
return target_->NewLogger(fname, result);
}
uint64_t NowMicros() {
return target_->NowMicros();
}
void SleepForMicroseconds(int micros) {
target_->SleepForMicroseconds(micros);
}
private:
Env* target_;
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_ENV_H_

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// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// A database can be configured with a custom FilterPolicy object.
// This object is responsible for creating a small filter from a set
// of keys. These filters are stored in leveldb and are consulted
// automatically by leveldb to decide whether or not to read some
// information from disk. In many cases, a filter can cut down the
// number of disk seeks form a handful to a single disk seek per
// DB::Get() call.
//
// Most people will want to use the builtin bloom filter support (see
// NewBloomFilterPolicy() below).
#ifndef STORAGE_LEVELDB_INCLUDE_FILTER_POLICY_H_
#define STORAGE_LEVELDB_INCLUDE_FILTER_POLICY_H_
#include <string>
namespace leveldb {
class Slice;
class FilterPolicy {
public:
virtual ~FilterPolicy();
// Return the name of this policy. Note that if the filter encoding
// changes in an incompatible way, the name returned by this method
// must be changed. Otherwise, old incompatible filters may be
// passed to methods of this type.
virtual const char* Name() const = 0;
// keys[0,n-1] contains a list of keys (potentially with duplicates)
// that are ordered according to the user supplied comparator.
// Append a filter that summarizes keys[0,n-1] to *dst.
//
// Warning: do not change the initial contents of *dst. Instead,
// append the newly constructed filter to *dst.
virtual void CreateFilter(const Slice* keys, int n, std::string* dst)
const = 0;
// "filter" contains the data appended by a preceding call to
// CreateFilter() on this class. This method must return true if
// the key was in the list of keys passed to CreateFilter().
// This method may return true or false if the key was not on the
// list, but it should aim to return false with a high probability.
virtual bool KeyMayMatch(const Slice& key, const Slice& filter) const = 0;
};
// Return a new filter policy that uses a bloom filter with approximately
// the specified number of bits per key. A good value for bits_per_key
// is 10, which yields a filter with ~ 1% false positive rate.
//
// Callers must delete the result after any database that is using the
// result has been closed.
//
// Note: if you are using a custom comparator that ignores some parts
// of the keys being compared, you must not use NewBloomFilterPolicy()
// and must provide your own FilterPolicy that also ignores the
// corresponding parts of the keys. For example, if the comparator
// ignores trailing spaces, it would be incorrect to use a
// FilterPolicy (like NewBloomFilterPolicy) that does not ignore
// trailing spaces in keys.
extern const FilterPolicy* NewBloomFilterPolicy(int bits_per_key);
}
#endif // STORAGE_LEVELDB_INCLUDE_FILTER_POLICY_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// An iterator yields a sequence of key/value pairs from a source.
// The following class defines the interface. Multiple implementations
// are provided by this library. In particular, iterators are provided
// to access the contents of a Table or a DB.
//
// Multiple threads can invoke const methods on an Iterator without
// external synchronization, but if any of the threads may call a
// non-const method, all threads accessing the same Iterator must use
// external synchronization.
#ifndef STORAGE_LEVELDB_INCLUDE_ITERATOR_H_
#define STORAGE_LEVELDB_INCLUDE_ITERATOR_H_
#include "leveldb/slice.h"
#include "leveldb/status.h"
namespace leveldb {
class Iterator {
public:
Iterator();
virtual ~Iterator();
// An iterator is either positioned at a key/value pair, or
// not valid. This method returns true iff the iterator is valid.
virtual bool Valid() const = 0;
// Position at the first key in the source. The iterator is Valid()
// after this call iff the source is not empty.
virtual void SeekToFirst() = 0;
// Position at the last key in the source. The iterator is
// Valid() after this call iff the source is not empty.
virtual void SeekToLast() = 0;
// Position at the first key in the source that at or past target
// The iterator is Valid() after this call iff the source contains
// an entry that comes at or past target.
virtual void Seek(const Slice& target) = 0;
// Moves to the next entry in the source. After this call, Valid() is
// true iff the iterator was not positioned at the last entry in the source.
// REQUIRES: Valid()
virtual void Next() = 0;
// Moves to the previous entry in the source. After this call, Valid() is
// true iff the iterator was not positioned at the first entry in source.
// REQUIRES: Valid()
virtual void Prev() = 0;
// Return the key for the current entry. The underlying storage for
// the returned slice is valid only until the next modification of
// the iterator.
// REQUIRES: Valid()
virtual Slice key() const = 0;
// Return the value for the current entry. The underlying storage for
// the returned slice is valid only until the next modification of
// the iterator.
// REQUIRES: !AtEnd() && !AtStart()
virtual Slice value() const = 0;
// If an error has occurred, return it. Else return an ok status.
virtual Status status() const = 0;
// Clients are allowed to register function/arg1/arg2 triples that
// will be invoked when this iterator is destroyed.
//
// Note that unlike all of the preceding methods, this method is
// not abstract and therefore clients should not override it.
typedef void (*CleanupFunction)(void* arg1, void* arg2);
void RegisterCleanup(CleanupFunction function, void* arg1, void* arg2);
private:
struct Cleanup {
CleanupFunction function;
void* arg1;
void* arg2;
Cleanup* next;
};
Cleanup cleanup_;
// No copying allowed
Iterator(const Iterator&);
void operator=(const Iterator&);
};
// Return an empty iterator (yields nothing).
extern Iterator* NewEmptyIterator();
// Return an empty iterator with the specified status.
extern Iterator* NewErrorIterator(const Status& status);
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_ITERATOR_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_INCLUDE_OPTIONS_H_
#define STORAGE_LEVELDB_INCLUDE_OPTIONS_H_
#include <stddef.h>
namespace leveldb {
class Cache;
class Comparator;
class Env;
class FilterPolicy;
class Logger;
class Snapshot;
// DB contents are stored in a set of blocks, each of which holds a
// sequence of key,value pairs. Each block may be compressed before
// being stored in a file. The following enum describes which
// compression method (if any) is used to compress a block.
enum CompressionType {
// NOTE: do not change the values of existing entries, as these are
// part of the persistent format on disk.
kNoCompression = 0x0,
kSnappyCompression = 0x1
};
// Options to control the behavior of a database (passed to DB::Open)
struct Options {
// -------------------
// Parameters that affect behavior
// Comparator used to define the order of keys in the table.
// Default: a comparator that uses lexicographic byte-wise ordering
//
// REQUIRES: The client must ensure that the comparator supplied
// here has the same name and orders keys *exactly* the same as the
// comparator provided to previous open calls on the same DB.
const Comparator* comparator;
// If true, the database will be created if it is missing.
// Default: false
bool create_if_missing;
// If true, an error is raised if the database already exists.
// Default: false
bool error_if_exists;
// If true, the implementation will do aggressive checking of the
// data it is processing and will stop early if it detects any
// errors. This may have unforeseen ramifications: for example, a
// corruption of one DB entry may cause a large number of entries to
// become unreadable or for the entire DB to become unopenable.
// Default: false
bool paranoid_checks;
// Use the specified object to interact with the environment,
// e.g. to read/write files, schedule background work, etc.
// Default: Env::Default()
Env* env;
// Any internal progress/error information generated by the db will
// be written to info_log if it is non-NULL, or to a file stored
// in the same directory as the DB contents if info_log is NULL.
// Default: NULL
Logger* info_log;
// -------------------
// Parameters that affect performance
// Amount of data to build up in memory (backed by an unsorted log
// on disk) before converting to a sorted on-disk file.
//
// Larger values increase performance, especially during bulk loads.
// Up to two write buffers may be held in memory at the same time,
// so you may wish to adjust this parameter to control memory usage.
// Also, a larger write buffer will result in a longer recovery time
// the next time the database is opened.
//
// Default: 4MB
size_t write_buffer_size;
// Number of open files that can be used by the DB. You may need to
// increase this if your database has a large working set (budget
// one open file per 2MB of working set).
//
// Default: 1000
int max_open_files;
// Control over blocks (user data is stored in a set of blocks, and
// a block is the unit of reading from disk).
// If non-NULL, use the specified cache for blocks.
// If NULL, leveldb will automatically create and use an 8MB internal cache.
// Default: NULL
Cache* block_cache;
// Approximate size of user data packed per block. Note that the
// block size specified here corresponds to uncompressed data. The
// actual size of the unit read from disk may be smaller if
// compression is enabled. This parameter can be changed dynamically.
//
// Default: 4K
size_t block_size;
// Number of keys between restart points for delta encoding of keys.
// This parameter can be changed dynamically. Most clients should
// leave this parameter alone.
//
// Default: 16
int block_restart_interval;
// Compress blocks using the specified compression algorithm. This
// parameter can be changed dynamically.
//
// Default: kSnappyCompression, which gives lightweight but fast
// compression.
//
// Typical speeds of kSnappyCompression on an Intel(R) Core(TM)2 2.4GHz:
// ~200-500MB/s compression
// ~400-800MB/s decompression
// Note that these speeds are significantly faster than most
// persistent storage speeds, and therefore it is typically never
// worth switching to kNoCompression. Even if the input data is
// incompressible, the kSnappyCompression implementation will
// efficiently detect that and will switch to uncompressed mode.
CompressionType compression;
// If non-NULL, use the specified filter policy to reduce disk reads.
// Many applications will benefit from passing the result of
// NewBloomFilterPolicy() here.
//
// Default: NULL
const FilterPolicy* filter_policy;
// Create an Options object with default values for all fields.
Options();
};
// Options that control read operations
struct ReadOptions {
// If true, all data read from underlying storage will be
// verified against corresponding checksums.
// Default: false
bool verify_checksums;
// Should the data read for this iteration be cached in memory?
// Callers may wish to set this field to false for bulk scans.
// Default: true
bool fill_cache;
// If "snapshot" is non-NULL, read as of the supplied snapshot
// (which must belong to the DB that is being read and which must
// not have been released). If "snapshot" is NULL, use an impliicit
// snapshot of the state at the beginning of this read operation.
// Default: NULL
const Snapshot* snapshot;
ReadOptions()
: verify_checksums(false),
fill_cache(true),
snapshot(NULL) {
}
};
// Options that control write operations
struct WriteOptions {
// If true, the write will be flushed from the operating system
// buffer cache (by calling WritableFile::Sync()) before the write
// is considered complete. If this flag is true, writes will be
// slower.
//
// If this flag is false, and the machine crashes, some recent
// writes may be lost. Note that if it is just the process that
// crashes (i.e., the machine does not reboot), no writes will be
// lost even if sync==false.
//
// In other words, a DB write with sync==false has similar
// crash semantics as the "write()" system call. A DB write
// with sync==true has similar crash semantics to a "write()"
// system call followed by "fsync()".
//
// Default: false
bool sync;
WriteOptions()
: sync(false) {
}
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_OPTIONS_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// Slice is a simple structure containing a pointer into some external
// storage and a size. The user of a Slice must ensure that the slice
// is not used after the corresponding external storage has been
// deallocated.
//
// Multiple threads can invoke const methods on a Slice without
// external synchronization, but if any of the threads may call a
// non-const method, all threads accessing the same Slice must use
// external synchronization.
#ifndef STORAGE_LEVELDB_INCLUDE_SLICE_H_
#define STORAGE_LEVELDB_INCLUDE_SLICE_H_
#include <assert.h>
#include <stddef.h>
#include <string.h>
#include <string>
namespace leveldb {
class Slice {
public:
// Create an empty slice.
Slice() : data_(""), size_(0) { }
// Create a slice that refers to d[0,n-1].
Slice(const char* d, size_t n) : data_(d), size_(n) { }
// Create a slice that refers to the contents of "s"
Slice(const std::string& s) : data_(s.data()), size_(s.size()) { }
// Create a slice that refers to s[0,strlen(s)-1]
Slice(const char* s) : data_(s), size_(strlen(s)) { }
// Return a pointer to the beginning of the referenced data
const char* data() const { return data_; }
// Return the length (in bytes) of the referenced data
size_t size() const { return size_; }
// Return true iff the length of the referenced data is zero
bool empty() const { return size_ == 0; }
// Return the ith byte in the referenced data.
// REQUIRES: n < size()
char operator[](size_t n) const {
assert(n < size());
return data_[n];
}
// Change this slice to refer to an empty array
void clear() { data_ = ""; size_ = 0; }
// Drop the first "n" bytes from this slice.
void remove_prefix(size_t n) {
assert(n <= size());
data_ += n;
size_ -= n;
}
// Return a string that contains the copy of the referenced data.
std::string ToString() const { return std::string(data_, size_); }
// Three-way comparison. Returns value:
// < 0 iff "*this" < "b",
// == 0 iff "*this" == "b",
// > 0 iff "*this" > "b"
int compare(const Slice& b) const;
// Return true iff "x" is a prefix of "*this"
bool starts_with(const Slice& x) const {
return ((size_ >= x.size_) &&
(memcmp(data_, x.data_, x.size_) == 0));
}
private:
const char* data_;
size_t size_;
// Intentionally copyable
};
inline bool operator==(const Slice& x, const Slice& y) {
return ((x.size() == y.size()) &&
(memcmp(x.data(), y.data(), x.size()) == 0));
}
inline bool operator!=(const Slice& x, const Slice& y) {
return !(x == y);
}
inline int Slice::compare(const Slice& b) const {
const int min_len = (size_ < b.size_) ? size_ : b.size_;
int r = memcmp(data_, b.data_, min_len);
if (r == 0) {
if (size_ < b.size_) r = -1;
else if (size_ > b.size_) r = +1;
}
return r;
}
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_SLICE_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// A Status encapsulates the result of an operation. It may indicate success,
// or it may indicate an error with an associated error message.
//
// Multiple threads can invoke const methods on a Status without
// external synchronization, but if any of the threads may call a
// non-const method, all threads accessing the same Status must use
// external synchronization.
#ifndef STORAGE_LEVELDB_INCLUDE_STATUS_H_
#define STORAGE_LEVELDB_INCLUDE_STATUS_H_
#include <string>
#include "leveldb/slice.h"
namespace leveldb {
class Status {
public:
// Create a success status.
Status() : state_(NULL) { }
~Status() { delete[] state_; }
// Copy the specified status.
Status(const Status& s);
void operator=(const Status& s);
// Return a success status.
static Status OK() { return Status(); }
// Return error status of an appropriate type.
static Status NotFound(const Slice& msg, const Slice& msg2 = Slice()) {
return Status(kNotFound, msg, msg2);
}
static Status Corruption(const Slice& msg, const Slice& msg2 = Slice()) {
return Status(kCorruption, msg, msg2);
}
static Status NotSupported(const Slice& msg, const Slice& msg2 = Slice()) {
return Status(kNotSupported, msg, msg2);
}
static Status InvalidArgument(const Slice& msg, const Slice& msg2 = Slice()) {
return Status(kInvalidArgument, msg, msg2);
}
static Status IOError(const Slice& msg, const Slice& msg2 = Slice()) {
return Status(kIOError, msg, msg2);
}
// Returns true iff the status indicates success.
bool ok() const { return (state_ == NULL); }
// Returns true iff the status indicates a NotFound error.
bool IsNotFound() const { return code() == kNotFound; }
// Returns true iff the status indicates a Corruption error.
bool IsCorruption() const { return code() == kCorruption; }
// Returns true iff the status indicates an IOError.
bool IsIOError() const { return code() == kIOError; }
// Return a string representation of this status suitable for printing.
// Returns the string "OK" for success.
std::string ToString() const;
private:
// OK status has a NULL state_. Otherwise, state_ is a new[] array
// of the following form:
// state_[0..3] == length of message
// state_[4] == code
// state_[5..] == message
const char* state_;
enum Code {
kOk = 0,
kNotFound = 1,
kCorruption = 2,
kNotSupported = 3,
kInvalidArgument = 4,
kIOError = 5
};
Code code() const {
return (state_ == NULL) ? kOk : static_cast<Code>(state_[4]);
}
Status(Code code, const Slice& msg, const Slice& msg2);
static const char* CopyState(const char* s);
};
inline Status::Status(const Status& s) {
state_ = (s.state_ == NULL) ? NULL : CopyState(s.state_);
}
inline void Status::operator=(const Status& s) {
// The following condition catches both aliasing (when this == &s),
// and the common case where both s and *this are ok.
if (state_ != s.state_) {
delete[] state_;
state_ = (s.state_ == NULL) ? NULL : CopyState(s.state_);
}
}
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_STATUS_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_INCLUDE_TABLE_H_
#define STORAGE_LEVELDB_INCLUDE_TABLE_H_
#include <stdint.h>
#include "leveldb/iterator.h"
namespace leveldb {
class Block;
class BlockHandle;
class Footer;
struct Options;
class RandomAccessFile;
struct ReadOptions;
class TableCache;
// A Table is a sorted map from strings to strings. Tables are
// immutable and persistent. A Table may be safely accessed from
// multiple threads without external synchronization.
class Table {
public:
// Attempt to open the table that is stored in bytes [0..file_size)
// of "file", and read the metadata entries necessary to allow
// retrieving data from the table.
//
// If successful, returns ok and sets "*table" to the newly opened
// table. The client should delete "*table" when no longer needed.
// If there was an error while initializing the table, sets "*table"
// to NULL and returns a non-ok status. Does not take ownership of
// "*source", but the client must ensure that "source" remains live
// for the duration of the returned table's lifetime.
//
// *file must remain live while this Table is in use.
static Status Open(const Options& options,
RandomAccessFile* file,
uint64_t file_size,
Table** table);
~Table();
// Returns a new iterator over the table contents.
// The result of NewIterator() is initially invalid (caller must
// call one of the Seek methods on the iterator before using it).
Iterator* NewIterator(const ReadOptions&) const;
// Given a key, return an approximate byte offset in the file where
// the data for that key begins (or would begin if the key were
// present in the file). The returned value is in terms of file
// bytes, and so includes effects like compression of the underlying data.
// E.g., the approximate offset of the last key in the table will
// be close to the file length.
uint64_t ApproximateOffsetOf(const Slice& key) const;
private:
struct Rep;
Rep* rep_;
explicit Table(Rep* rep) { rep_ = rep; }
static Iterator* BlockReader(void*, const ReadOptions&, const Slice&);
// Calls (*handle_result)(arg, ...) with the entry found after a call
// to Seek(key). May not make such a call if filter policy says
// that key is not present.
friend class TableCache;
Status InternalGet(
const ReadOptions&, const Slice& key,
void* arg,
void (*handle_result)(void* arg, const Slice& k, const Slice& v));
void ReadMeta(const Footer& footer);
void ReadFilter(const Slice& filter_handle_value);
// No copying allowed
Table(const Table&);
void operator=(const Table&);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_TABLE_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// TableBuilder provides the interface used to build a Table
// (an immutable and sorted map from keys to values).
//
// Multiple threads can invoke const methods on a TableBuilder without
// external synchronization, but if any of the threads may call a
// non-const method, all threads accessing the same TableBuilder must use
// external synchronization.
#ifndef STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_
#define STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_
#include <stdint.h>
#include "leveldb/options.h"
#include "leveldb/status.h"
namespace leveldb {
class BlockBuilder;
class BlockHandle;
class WritableFile;
class TableBuilder {
public:
// Create a builder that will store the contents of the table it is
// building in *file. Does not close the file. It is up to the
// caller to close the file after calling Finish().
TableBuilder(const Options& options, WritableFile* file);
// REQUIRES: Either Finish() or Abandon() has been called.
~TableBuilder();
// Change the options used by this builder. Note: only some of the
// option fields can be changed after construction. If a field is
// not allowed to change dynamically and its value in the structure
// passed to the constructor is different from its value in the
// structure passed to this method, this method will return an error
// without changing any fields.
Status ChangeOptions(const Options& options);
// Add key,value to the table being constructed.
// REQUIRES: key is after any previously added key according to comparator.
// REQUIRES: Finish(), Abandon() have not been called
void Add(const Slice& key, const Slice& value);
// Advanced operation: flush any buffered key/value pairs to file.
// Can be used to ensure that two adjacent entries never live in
// the same data block. Most clients should not need to use this method.
// REQUIRES: Finish(), Abandon() have not been called
void Flush();
// Return non-ok iff some error has been detected.
Status status() const;
// Finish building the table. Stops using the file passed to the
// constructor after this function returns.
// REQUIRES: Finish(), Abandon() have not been called
Status Finish();
// Indicate that the contents of this builder should be abandoned. Stops
// using the file passed to the constructor after this function returns.
// If the caller is not going to call Finish(), it must call Abandon()
// before destroying this builder.
// REQUIRES: Finish(), Abandon() have not been called
void Abandon();
// Number of calls to Add() so far.
uint64_t NumEntries() const;
// Size of the file generated so far. If invoked after a successful
// Finish() call, returns the size of the final generated file.
uint64_t FileSize() const;
private:
bool ok() const { return status().ok(); }
void WriteBlock(BlockBuilder* block, BlockHandle* handle);
void WriteRawBlock(const Slice& data, CompressionType, BlockHandle* handle);
struct Rep;
Rep* rep_;
// No copying allowed
TableBuilder(const TableBuilder&);
void operator=(const TableBuilder&);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// WriteBatch holds a collection of updates to apply atomically to a DB.
//
// The updates are applied in the order in which they are added
// to the WriteBatch. For example, the value of "key" will be "v3"
// after the following batch is written:
//
// batch.Put("key", "v1");
// batch.Delete("key");
// batch.Put("key", "v2");
// batch.Put("key", "v3");
//
// Multiple threads can invoke const methods on a WriteBatch without
// external synchronization, but if any of the threads may call a
// non-const method, all threads accessing the same WriteBatch must use
// external synchronization.
#ifndef STORAGE_LEVELDB_INCLUDE_WRITE_BATCH_H_
#define STORAGE_LEVELDB_INCLUDE_WRITE_BATCH_H_
#include <string>
#include "leveldb/status.h"
namespace leveldb {
class Slice;
class WriteBatch {
public:
WriteBatch();
~WriteBatch();
// Store the mapping "key->value" in the database.
void Put(const Slice& key, const Slice& value);
// If the database contains a mapping for "key", erase it. Else do nothing.
void Delete(const Slice& key);
// Clear all updates buffered in this batch.
void Clear();
// Support for iterating over the contents of a batch.
class Handler {
public:
virtual ~Handler();
virtual void Put(const Slice& key, const Slice& value) = 0;
virtual void Delete(const Slice& key) = 0;
};
Status Iterate(Handler* handler) const;
private:
friend class WriteBatchInternal;
std::string rep_; // See comment in write_batch.cc for the format of rep_
// Intentionally copyable
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_WRITE_BATCH_H_

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This directory contains interfaces and implementations that isolate the
rest of the package from platform details.
Code in the rest of the package includes "port.h" from this directory.
"port.h" in turn includes a platform specific "port_<platform>.h" file
that provides the platform specific implementation.
See port_posix.h for an example of what must be provided in a platform
specific header file.

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
// AtomicPointer provides storage for a lock-free pointer.
// Platform-dependent implementation of AtomicPointer:
// - If the platform provides a cheap barrier, we use it with raw pointers
// - If cstdatomic is present (on newer versions of gcc, it is), we use
// a cstdatomic-based AtomicPointer. However we prefer the memory
// barrier based version, because at least on a gcc 4.4 32-bit build
// on linux, we have encountered a buggy <cstdatomic>
// implementation. Also, some <cstdatomic> implementations are much
// slower than a memory-barrier based implementation (~16ns for
// <cstdatomic> based acquire-load vs. ~1ns for a barrier based
// acquire-load).
// This code is based on atomicops-internals-* in Google's perftools:
// http://code.google.com/p/google-perftools/source/browse/#svn%2Ftrunk%2Fsrc%2Fbase
#ifndef PORT_ATOMIC_POINTER_H_
#define PORT_ATOMIC_POINTER_H_
#include <stdint.h>
#ifdef LEVELDB_CSTDATOMIC_PRESENT
#include <cstdatomic>
#endif
#ifdef OS_WIN
#include <windows.h>
#endif
#ifdef OS_MACOSX
#include <libkern/OSAtomic.h>
#endif
#if defined(_M_X64) || defined(__x86_64__)
#define ARCH_CPU_X86_FAMILY 1
#elif defined(_M_IX86) || defined(__i386__) || defined(__i386)
#define ARCH_CPU_X86_FAMILY 1
#elif defined(__ARMEL__)
#define ARCH_CPU_ARM_FAMILY 1
#elif defined(__ppc__) || defined(__powerpc__) || defined(__powerpc64__)
#define ARCH_CPU_PPC_FAMILY 1
#endif
namespace leveldb {
namespace port {
// Define MemoryBarrier() if available
// Windows on x86
#if defined(OS_WIN) && defined(COMPILER_MSVC) && defined(ARCH_CPU_X86_FAMILY)
// windows.h already provides a MemoryBarrier(void) macro
// http://msdn.microsoft.com/en-us/library/ms684208(v=vs.85).aspx
#define LEVELDB_HAVE_MEMORY_BARRIER
// Gcc on x86
#elif defined(ARCH_CPU_X86_FAMILY) && defined(__GNUC__)
inline void MemoryBarrier() {
// See http://gcc.gnu.org/ml/gcc/2003-04/msg01180.html for a discussion on
// this idiom. Also see http://en.wikipedia.org/wiki/Memory_ordering.
__asm__ __volatile__("" : : : "memory");
}
#define LEVELDB_HAVE_MEMORY_BARRIER
// Sun Studio
#elif defined(ARCH_CPU_X86_FAMILY) && defined(__SUNPRO_CC)
inline void MemoryBarrier() {
// See http://gcc.gnu.org/ml/gcc/2003-04/msg01180.html for a discussion on
// this idiom. Also see http://en.wikipedia.org/wiki/Memory_ordering.
asm volatile("" : : : "memory");
}
#define LEVELDB_HAVE_MEMORY_BARRIER
// Mac OS
#elif defined(OS_MACOSX)
inline void MemoryBarrier() {
OSMemoryBarrier();
}
#define LEVELDB_HAVE_MEMORY_BARRIER
// ARM Linux
#elif defined(ARCH_CPU_ARM_FAMILY) && defined(__linux__)
typedef void (*LinuxKernelMemoryBarrierFunc)(void);
// The Linux ARM kernel provides a highly optimized device-specific memory
// barrier function at a fixed memory address that is mapped in every
// user-level process.
//
// This beats using CPU-specific instructions which are, on single-core
// devices, un-necessary and very costly (e.g. ARMv7-A "dmb" takes more
// than 180ns on a Cortex-A8 like the one on a Nexus One). Benchmarking
// shows that the extra function call cost is completely negligible on
// multi-core devices.
//
inline void MemoryBarrier() {
(*(LinuxKernelMemoryBarrierFunc)0xffff0fa0)();
}
#define LEVELDB_HAVE_MEMORY_BARRIER
// PPC
#elif defined(ARCH_CPU_PPC_FAMILY) && defined(__GNUC__)
inline void MemoryBarrier() {
// TODO for some powerpc expert: is there a cheaper suitable variant?
// Perhaps by having separate barriers for acquire and release ops.
asm volatile("sync" : : : "memory");
}
#define LEVELDB_HAVE_MEMORY_BARRIER
#endif
// AtomicPointer built using platform-specific MemoryBarrier()
#if defined(LEVELDB_HAVE_MEMORY_BARRIER)
class AtomicPointer {
private:
void* rep_;
public:
AtomicPointer() { }
explicit AtomicPointer(void* p) : rep_(p) {}
inline void* NoBarrier_Load() const { return rep_; }
inline void NoBarrier_Store(void* v) { rep_ = v; }
inline void* Acquire_Load() const {
void* result = rep_;
MemoryBarrier();
return result;
}
inline void Release_Store(void* v) {
MemoryBarrier();
rep_ = v;
}
};
// AtomicPointer based on <cstdatomic>
#elif defined(LEVELDB_CSTDATOMIC_PRESENT)
class AtomicPointer {
private:
std::atomic<void*> rep_;
public:
AtomicPointer() { }
explicit AtomicPointer(void* v) : rep_(v) { }
inline void* Acquire_Load() const {
return rep_.load(std::memory_order_acquire);
}
inline void Release_Store(void* v) {
rep_.store(v, std::memory_order_release);
}
inline void* NoBarrier_Load() const {
return rep_.load(std::memory_order_relaxed);
}
inline void NoBarrier_Store(void* v) {
rep_.store(v, std::memory_order_relaxed);
}
};
// Atomic pointer based on sparc memory barriers
#elif defined(__sparcv9) && defined(__GNUC__)
class AtomicPointer {
private:
void* rep_;
public:
AtomicPointer() { }
explicit AtomicPointer(void* v) : rep_(v) { }
inline void* Acquire_Load() const {
void* val;
__asm__ __volatile__ (
"ldx [%[rep_]], %[val] \n\t"
"membar #LoadLoad|#LoadStore \n\t"
: [val] "=r" (val)
: [rep_] "r" (&rep_)
: "memory");
return val;
}
inline void Release_Store(void* v) {
__asm__ __volatile__ (
"membar #LoadStore|#StoreStore \n\t"
"stx %[v], [%[rep_]] \n\t"
:
: [rep_] "r" (&rep_), [v] "r" (v)
: "memory");
}
inline void* NoBarrier_Load() const { return rep_; }
inline void NoBarrier_Store(void* v) { rep_ = v; }
};
// Atomic pointer based on ia64 acq/rel
#elif defined(__ia64) && defined(__GNUC__)
class AtomicPointer {
private:
void* rep_;
public:
AtomicPointer() { }
explicit AtomicPointer(void* v) : rep_(v) { }
inline void* Acquire_Load() const {
void* val ;
__asm__ __volatile__ (
"ld8.acq %[val] = [%[rep_]] \n\t"
: [val] "=r" (val)
: [rep_] "r" (&rep_)
: "memory"
);
return val;
}
inline void Release_Store(void* v) {
__asm__ __volatile__ (
"st8.rel [%[rep_]] = %[v] \n\t"
:
: [rep_] "r" (&rep_), [v] "r" (v)
: "memory"
);
}
inline void* NoBarrier_Load() const { return rep_; }
inline void NoBarrier_Store(void* v) { rep_ = v; }
};
// We have neither MemoryBarrier(), nor <cstdatomic>
#else
#error Please implement AtomicPointer for this platform.
#endif
#undef LEVELDB_HAVE_MEMORY_BARRIER
#undef ARCH_CPU_X86_FAMILY
#undef ARCH_CPU_ARM_FAMILY
#undef ARCH_CPU_PPC_FAMILY
} // namespace port
} // namespace leveldb
#endif // PORT_ATOMIC_POINTER_H_

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src/leveldb/port/port.h
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_PORT_PORT_H_
#define STORAGE_LEVELDB_PORT_PORT_H_
#include <string.h>
// Include the appropriate platform specific file below. If you are
// porting to a new platform, see "port_example.h" for documentation
// of what the new port_<platform>.h file must provide.
#if defined(LEVELDB_PLATFORM_POSIX)
# include "port/port_posix.h"
#elif defined(LEVELDB_PLATFORM_CHROMIUM)
# include "port/port_chromium.h"
#endif
#endif // STORAGE_LEVELDB_PORT_PORT_H_

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src/leveldb/port/port_example.h
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// This file contains the specification, but not the implementations,
// of the types/operations/etc. that should be defined by a platform
// specific port_<platform>.h file. Use this file as a reference for
// how to port this package to a new platform.
#ifndef STORAGE_LEVELDB_PORT_PORT_EXAMPLE_H_
#define STORAGE_LEVELDB_PORT_PORT_EXAMPLE_H_
namespace leveldb {
namespace port {
// TODO(jorlow): Many of these belong more in the environment class rather than
// here. We should try moving them and see if it affects perf.
// The following boolean constant must be true on a little-endian machine
// and false otherwise.
static const bool kLittleEndian = true /* or some other expression */;
// ------------------ Threading -------------------
// A Mutex represents an exclusive lock.
class Mutex {
public:
Mutex();
~Mutex();
// Lock the mutex. Waits until other lockers have exited.
// Will deadlock if the mutex is already locked by this thread.
void Lock();
// Unlock the mutex.
// REQUIRES: This mutex was locked by this thread.
void Unlock();
// Optionally crash if this thread does not hold this mutex.
// The implementation must be fast, especially if NDEBUG is
// defined. The implementation is allowed to skip all checks.
void AssertHeld();
};
class CondVar {
public:
explicit CondVar(Mutex* mu);
~CondVar();
// Atomically release *mu and block on this condition variable until
// either a call to SignalAll(), or a call to Signal() that picks
// this thread to wakeup.
// REQUIRES: this thread holds *mu
void Wait();
// If there are some threads waiting, wake up at least one of them.
void Signal();
// Wake up all waiting threads.
void SignallAll();
};
// Thread-safe initialization.
// Used as follows:
// static port::OnceType init_control = LEVELDB_ONCE_INIT;
// static void Initializer() { ... do something ...; }
// ...
// port::InitOnce(&init_control, &Initializer);
typedef intptr_t OnceType;
#define LEVELDB_ONCE_INIT 0
extern void InitOnce(port::OnceType*, void (*initializer)());
// A type that holds a pointer that can be read or written atomically
// (i.e., without word-tearing.)
class AtomicPointer {
private:
intptr_t rep_;
public:
// Initialize to arbitrary value
AtomicPointer();
// Initialize to hold v
explicit AtomicPointer(void* v) : rep_(v) { }
// Read and return the stored pointer with the guarantee that no
// later memory access (read or write) by this thread can be
// reordered ahead of this read.
void* Acquire_Load() const;
// Set v as the stored pointer with the guarantee that no earlier
// memory access (read or write) by this thread can be reordered
// after this store.
void Release_Store(void* v);
// Read the stored pointer with no ordering guarantees.
void* NoBarrier_Load() const;
// Set va as the stored pointer with no ordering guarantees.
void NoBarrier_Store(void* v);
};
// ------------------ Compression -------------------
// Store the snappy compression of "input[0,input_length-1]" in *output.
// Returns false if snappy is not supported by this port.
extern bool Snappy_Compress(const char* input, size_t input_length,
std::string* output);
// If input[0,input_length-1] looks like a valid snappy compressed
// buffer, store the size of the uncompressed data in *result and
// return true. Else return false.
extern bool Snappy_GetUncompressedLength(const char* input, size_t length,
size_t* result);
// Attempt to snappy uncompress input[0,input_length-1] into *output.
// Returns true if successful, false if the input is invalid lightweight
// compressed data.
//
// REQUIRES: at least the first "n" bytes of output[] must be writable
// where "n" is the result of a successful call to
// Snappy_GetUncompressedLength.
extern bool Snappy_Uncompress(const char* input_data, size_t input_length,
char* output);
// ------------------ Miscellaneous -------------------
// If heap profiling is not supported, returns false.
// Else repeatedly calls (*func)(arg, data, n) and then returns true.
// The concatenation of all "data[0,n-1]" fragments is the heap profile.
extern bool GetHeapProfile(void (*func)(void*, const char*, int), void* arg);
} // namespace port
} // namespace leveldb
#endif // STORAGE_LEVELDB_PORT_PORT_EXAMPLE_H_

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src/leveldb/port/port_posix.cc
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "port/port_posix.h"
#include <cstdlib>
#include <stdio.h>
#include <string.h>
#include "util/logging.h"
namespace leveldb {
namespace port {
static void PthreadCall(const char* label, int result) {
if (result != 0) {
fprintf(stderr, "pthread %s: %s\n", label, strerror(result));
abort();
}
}
Mutex::Mutex() { PthreadCall("init mutex", pthread_mutex_init(&mu_, NULL)); }
Mutex::~Mutex() { PthreadCall("destroy mutex", pthread_mutex_destroy(&mu_)); }
void Mutex::Lock() { PthreadCall("lock", pthread_mutex_lock(&mu_)); }
void Mutex::Unlock() { PthreadCall("unlock", pthread_mutex_unlock(&mu_)); }
CondVar::CondVar(Mutex* mu)
: mu_(mu) {
PthreadCall("init cv", pthread_cond_init(&cv_, NULL));
}
CondVar::~CondVar() { PthreadCall("destroy cv", pthread_cond_destroy(&cv_)); }
void CondVar::Wait() {
PthreadCall("wait", pthread_cond_wait(&cv_, &mu_->mu_));
}
void CondVar::Signal() {
PthreadCall("signal", pthread_cond_signal(&cv_));
}
void CondVar::SignalAll() {
PthreadCall("broadcast", pthread_cond_broadcast(&cv_));
}
void InitOnce(OnceType* once, void (*initializer)()) {
PthreadCall("once", pthread_once(once, initializer));
}
} // namespace port
} // namespace leveldb

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src/leveldb/port/port_posix.h
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// See port_example.h for documentation for the following types/functions.
#ifndef STORAGE_LEVELDB_PORT_PORT_POSIX_H_
#define STORAGE_LEVELDB_PORT_PORT_POSIX_H_
#undef PLATFORM_IS_LITTLE_ENDIAN
#if defined(OS_MACOSX)
#include <machine/endian.h>
#if defined(__DARWIN_LITTLE_ENDIAN) && defined(__DARWIN_BYTE_ORDER)
#define PLATFORM_IS_LITTLE_ENDIAN \
(__DARWIN_BYTE_ORDER == __DARWIN_LITTLE_ENDIAN)
#endif
#elif defined(OS_SOLARIS)
#include <sys/isa_defs.h>
#ifdef _LITTLE_ENDIAN
#define PLATFORM_IS_LITTLE_ENDIAN true
#else
#define PLATFORM_IS_LITTLE_ENDIAN false
#endif
#elif defined(OS_FREEBSD)
#include <sys/types.h>
#include <sys/endian.h>
#define PLATFORM_IS_LITTLE_ENDIAN (_BYTE_ORDER == _LITTLE_ENDIAN)
#elif defined(OS_OPENBSD) || defined(OS_NETBSD) ||\
defined(OS_DRAGONFLYBSD) || defined(OS_ANDROID)
#include <sys/types.h>
#include <sys/endian.h>
#elif defined(OS_HPUX)
#define PLATFORM_IS_LITTLE_ENDIAN false
#else
#include <endian.h>
#endif
#include <pthread.h>
#ifdef SNAPPY
#include <snappy.h>
#endif
#include <stdint.h>
#include <string>
#include "port/atomic_pointer.h"
#ifndef PLATFORM_IS_LITTLE_ENDIAN
#define PLATFORM_IS_LITTLE_ENDIAN (__BYTE_ORDER == __LITTLE_ENDIAN)
#endif
#if defined(OS_MACOSX) || defined(OS_SOLARIS) || defined(OS_FREEBSD) ||\
defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_DRAGONFLYBSD) ||\
defined(OS_ANDROID) || defined(OS_HPUX)
// Use fread/fwrite/fflush on platforms without _unlocked variants
#define fread_unlocked fread
#define fwrite_unlocked fwrite
#define fflush_unlocked fflush
#endif
#if defined(OS_MACOSX) || defined(OS_FREEBSD) ||\
defined(OS_OPENBSD) || defined(OS_DRAGONFLYBSD)
// Use fsync() on platforms without fdatasync()
#define fdatasync fsync
#endif
#if defined(OS_ANDROID) && __ANDROID_API__ < 9
// fdatasync() was only introduced in API level 9 on Android. Use fsync()
// when targetting older platforms.
#define fdatasync fsync
#endif
namespace leveldb {
namespace port {
static const bool kLittleEndian = PLATFORM_IS_LITTLE_ENDIAN;
#undef PLATFORM_IS_LITTLE_ENDIAN
class CondVar;
class Mutex {
public:
Mutex();
~Mutex();
void Lock();
void Unlock();
void AssertHeld() { }
private:
friend class CondVar;
pthread_mutex_t mu_;
// No copying
Mutex(const Mutex&);
void operator=(const Mutex&);
};
class CondVar {
public:
explicit CondVar(Mutex* mu);
~CondVar();
void Wait();
void Signal();
void SignalAll();
private:
pthread_cond_t cv_;
Mutex* mu_;
};
typedef pthread_once_t OnceType;
#define LEVELDB_ONCE_INIT PTHREAD_ONCE_INIT
extern void InitOnce(OnceType* once, void (*initializer)());
inline bool Snappy_Compress(const char* input, size_t length,
::std::string* output) {
#ifdef SNAPPY
output->resize(snappy::MaxCompressedLength(length));
size_t outlen;
snappy::RawCompress(input, length, &(*output)[0], &outlen);
output->resize(outlen);
return true;
#endif
return false;
}
inline bool Snappy_GetUncompressedLength(const char* input, size_t length,
size_t* result) {
#ifdef SNAPPY
return snappy::GetUncompressedLength(input, length, result);
#else
return false;
#endif
}
inline bool Snappy_Uncompress(const char* input, size_t length,
char* output) {
#ifdef SNAPPY
return snappy::RawUncompress(input, length, output);
#else
return false;
#endif
}
inline bool GetHeapProfile(void (*func)(void*, const char*, int), void* arg) {
return false;
}
} // namespace port
} // namespace leveldb
#endif // STORAGE_LEVELDB_PORT_PORT_POSIX_H_

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// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_PORT_THREAD_ANNOTATIONS_H
// Some environments provide custom macros to aid in static thread-safety
// analysis. Provide empty definitions of such macros unless they are already
// defined.
#ifndef EXCLUSIVE_LOCKS_REQUIRED
#define EXCLUSIVE_LOCKS_REQUIRED(...)
#endif
#ifndef SHARED_LOCKS_REQUIRED
#define SHARED_LOCKS_REQUIRED(...)
#endif
#ifndef LOCKS_EXCLUDED
#define LOCKS_EXCLUDED(...)
#endif
#ifndef LOCK_RETURNED
#define LOCK_RETURNED(x)
#endif
#ifndef LOCKABLE
#define LOCKABLE
#endif
#ifndef SCOPED_LOCKABLE
#define SCOPED_LOCKABLE
#endif
#ifndef EXCLUSIVE_LOCK_FUNCTION
#define EXCLUSIVE_LOCK_FUNCTION(...)
#endif
#ifndef SHARED_LOCK_FUNCTION
#define SHARED_LOCK_FUNCTION(...)
#endif
#ifndef EXCLUSIVE_TRYLOCK_FUNCTION
#define EXCLUSIVE_TRYLOCK_FUNCTION(...)
#endif
#ifndef SHARED_TRYLOCK_FUNCTION
#define SHARED_TRYLOCK_FUNCTION(...)
#endif
#ifndef UNLOCK_FUNCTION
#define UNLOCK_FUNCTION(...)
#endif
#ifndef NO_THREAD_SAFETY_ANALYSIS
#define NO_THREAD_SAFETY_ANALYSIS
#endif
#endif // STORAGE_LEVELDB_PORT_THREAD_ANNOTATIONS_H

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src/leveldb/port/win/stdint.h
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
// MSVC didn't ship with this file until the 2010 version.
#ifndef STORAGE_LEVELDB_PORT_WIN_STDINT_H_
#define STORAGE_LEVELDB_PORT_WIN_STDINT_H_
#if !defined(_MSC_VER)
#error This file should only be included when compiling with MSVC.
#endif
// Define C99 equivalent types.
typedef signed char int8_t;
typedef signed short int16_t;
typedef signed int int32_t;
typedef signed long long int64_t;
typedef unsigned char uint8_t;
typedef unsigned short uint16_t;
typedef unsigned int uint32_t;
typedef unsigned long long uint64_t;
#endif // STORAGE_LEVELDB_PORT_WIN_STDINT_H_

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src/leveldb/table/block.cc
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// Decodes the blocks generated by block_builder.cc.
#include "table/block.h"
#include <vector>
#include <algorithm>
#include "leveldb/comparator.h"
#include "table/format.h"
#include "util/coding.h"
#include "util/logging.h"
namespace leveldb {
inline uint32_t Block::NumRestarts() const {
assert(size_ >= 2*sizeof(uint32_t));
return DecodeFixed32(data_ + size_ - sizeof(uint32_t));
}
Block::Block(const BlockContents& contents)
: data_(contents.data.data()),
size_(contents.data.size()),
owned_(contents.heap_allocated) {
if (size_ < sizeof(uint32_t)) {
size_ = 0; // Error marker
} else {
restart_offset_ = size_ - (1 + NumRestarts()) * sizeof(uint32_t);
if (restart_offset_ > size_ - sizeof(uint32_t)) {
// The size is too small for NumRestarts() and therefore
// restart_offset_ wrapped around.
size_ = 0;
}
}
}
Block::~Block() {
if (owned_) {
delete[] data_;
}
}
// Helper routine: decode the next block entry starting at "p",
// storing the number of shared key bytes, non_shared key bytes,
// and the length of the value in "*shared", "*non_shared", and
// "*value_length", respectively. Will not derefence past "limit".
//
// If any errors are detected, returns NULL. Otherwise, returns a
// pointer to the key delta (just past the three decoded values).
static inline const char* DecodeEntry(const char* p, const char* limit,
uint32_t* shared,
uint32_t* non_shared,
uint32_t* value_length) {
if (limit - p < 3) return NULL;
*shared = reinterpret_cast<const unsigned char*>(p)[0];
*non_shared = reinterpret_cast<const unsigned char*>(p)[1];
*value_length = reinterpret_cast<const unsigned char*>(p)[2];
if ((*shared | *non_shared | *value_length) < 128) {
// Fast path: all three values are encoded in one byte each
p += 3;
} else {
if ((p = GetVarint32Ptr(p, limit, shared)) == NULL) return NULL;
if ((p = GetVarint32Ptr(p, limit, non_shared)) == NULL) return NULL;
if ((p = GetVarint32Ptr(p, limit, value_length)) == NULL) return NULL;
}
if (static_cast<uint32_t>(limit - p) < (*non_shared + *value_length)) {
return NULL;
}
return p;
}
class Block::Iter : public Iterator {
private:
const Comparator* const comparator_;
const char* const data_; // underlying block contents
uint32_t const restarts_; // Offset of restart array (list of fixed32)
uint32_t const num_restarts_; // Number of uint32_t entries in restart array
// current_ is offset in data_ of current entry. >= restarts_ if !Valid
uint32_t current_;
uint32_t restart_index_; // Index of restart block in which current_ falls
std::string key_;
Slice value_;
Status status_;
inline int Compare(const Slice& a, const Slice& b) const {
return comparator_->Compare(a, b);
}
// Return the offset in data_ just past the end of the current entry.
inline uint32_t NextEntryOffset() const {
return (value_.data() + value_.size()) - data_;
}
uint32_t GetRestartPoint(uint32_t index) {
assert(index < num_restarts_);
return DecodeFixed32(data_ + restarts_ + index * sizeof(uint32_t));
}
void SeekToRestartPoint(uint32_t index) {
key_.clear();
restart_index_ = index;
// current_ will be fixed by ParseNextKey();
// ParseNextKey() starts at the end of value_, so set value_ accordingly
uint32_t offset = GetRestartPoint(index);
value_ = Slice(data_ + offset, 0);
}
public:
Iter(const Comparator* comparator,
const char* data,
uint32_t restarts,
uint32_t num_restarts)
: comparator_(comparator),
data_(data),
restarts_(restarts),
num_restarts_(num_restarts),
current_(restarts_),
restart_index_(num_restarts_) {
assert(num_restarts_ > 0);
}
virtual bool Valid() const { return current_ < restarts_; }
virtual Status status() const { return status_; }
virtual Slice key() const {
assert(Valid());
return key_;
}
virtual Slice value() const {
assert(Valid());
return value_;
}
virtual void Next() {
assert(Valid());
ParseNextKey();
}
virtual void Prev() {
assert(Valid());
// Scan backwards to a restart point before current_
const uint32_t original = current_;
while (GetRestartPoint(restart_index_) >= original) {
if (restart_index_ == 0) {
// No more entries
current_ = restarts_;
restart_index_ = num_restarts_;
return;
}
restart_index_--;
}
SeekToRestartPoint(restart_index_);
do {
// Loop until end of current entry hits the start of original entry
} while (ParseNextKey() && NextEntryOffset() < original);
}
virtual void Seek(const Slice& target) {
// Binary search in restart array to find the last restart point
// with a key < target
uint32_t left = 0;
uint32_t right = num_restarts_ - 1;
while (left < right) {
uint32_t mid = (left + right + 1) / 2;
uint32_t region_offset = GetRestartPoint(mid);
uint32_t shared, non_shared, value_length;
const char* key_ptr = DecodeEntry(data_ + region_offset,
data_ + restarts_,
&shared, &non_shared, &value_length);
if (key_ptr == NULL || (shared != 0)) {
CorruptionError();
return;
}
Slice mid_key(key_ptr, non_shared);
if (Compare(mid_key, target) < 0) {
// Key at "mid" is smaller than "target". Therefore all
// blocks before "mid" are uninteresting.
left = mid;
} else {
// Key at "mid" is >= "target". Therefore all blocks at or
// after "mid" are uninteresting.
right = mid - 1;
}
}
// Linear search (within restart block) for first key >= target
SeekToRestartPoint(left);
while (true) {
if (!ParseNextKey()) {
return;
}
if (Compare(key_, target) >= 0) {
return;
}
}
}
virtual void SeekToFirst() {
SeekToRestartPoint(0);
ParseNextKey();
}
virtual void SeekToLast() {
SeekToRestartPoint(num_restarts_ - 1);
while (ParseNextKey() && NextEntryOffset() < restarts_) {
// Keep skipping
}
}
private:
void CorruptionError() {
current_ = restarts_;
restart_index_ = num_restarts_;
status_ = Status::Corruption("bad entry in block");
key_.clear();
value_.clear();
}
bool ParseNextKey() {
current_ = NextEntryOffset();
const char* p = data_ + current_;
const char* limit = data_ + restarts_; // Restarts come right after data
if (p >= limit) {
// No more entries to return. Mark as invalid.
current_ = restarts_;
restart_index_ = num_restarts_;
return false;
}
// Decode next entry
uint32_t shared, non_shared, value_length;
p = DecodeEntry(p, limit, &shared, &non_shared, &value_length);
if (p == NULL || key_.size() < shared) {
CorruptionError();
return false;
} else {
key_.resize(shared);
key_.append(p, non_shared);
value_ = Slice(p + non_shared, value_length);
while (restart_index_ + 1 < num_restarts_ &&
GetRestartPoint(restart_index_ + 1) < current_) {
++restart_index_;
}
return true;
}
}
};
Iterator* Block::NewIterator(const Comparator* cmp) {
if (size_ < 2*sizeof(uint32_t)) {
return NewErrorIterator(Status::Corruption("bad block contents"));
}
const uint32_t num_restarts = NumRestarts();
if (num_restarts == 0) {
return NewEmptyIterator();
} else {
return new Iter(cmp, data_, restart_offset_, num_restarts);
}
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_TABLE_BLOCK_H_
#define STORAGE_LEVELDB_TABLE_BLOCK_H_
#include <stddef.h>
#include <stdint.h>
#include "leveldb/iterator.h"
namespace leveldb {
struct BlockContents;
class Comparator;
class Block {
public:
// Initialize the block with the specified contents.
explicit Block(const BlockContents& contents);
~Block();
size_t size() const { return size_; }
Iterator* NewIterator(const Comparator* comparator);
private:
uint32_t NumRestarts() const;
const char* data_;
size_t size_;
uint32_t restart_offset_; // Offset in data_ of restart array
bool owned_; // Block owns data_[]
// No copying allowed
Block(const Block&);
void operator=(const Block&);
class Iter;
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_TABLE_BLOCK_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// BlockBuilder generates blocks where keys are prefix-compressed:
//
// When we store a key, we drop the prefix shared with the previous
// string. This helps reduce the space requirement significantly.
// Furthermore, once every K keys, we do not apply the prefix
// compression and store the entire key. We call this a "restart
// point". The tail end of the block stores the offsets of all of the
// restart points, and can be used to do a binary search when looking
// for a particular key. Values are stored as-is (without compression)
// immediately following the corresponding key.
//
// An entry for a particular key-value pair has the form:
// shared_bytes: varint32
// unshared_bytes: varint32
// value_length: varint32
// key_delta: char[unshared_bytes]
// value: char[value_length]
// shared_bytes == 0 for restart points.
//
// The trailer of the block has the form:
// restarts: uint32[num_restarts]
// num_restarts: uint32
// restarts[i] contains the offset within the block of the ith restart point.
#include "table/block_builder.h"
#include <algorithm>
#include <assert.h>
#include "leveldb/comparator.h"
#include "leveldb/table_builder.h"
#include "util/coding.h"
namespace leveldb {
BlockBuilder::BlockBuilder(const Options* options)
: options_(options),
restarts_(),
counter_(0),
finished_(false) {
assert(options->block_restart_interval >= 1);
restarts_.push_back(0); // First restart point is at offset 0
}
void BlockBuilder::Reset() {
buffer_.clear();
restarts_.clear();
restarts_.push_back(0); // First restart point is at offset 0
counter_ = 0;
finished_ = false;
last_key_.clear();
}
size_t BlockBuilder::CurrentSizeEstimate() const {
return (buffer_.size() + // Raw data buffer
restarts_.size() * sizeof(uint32_t) + // Restart array
sizeof(uint32_t)); // Restart array length
}
Slice BlockBuilder::Finish() {
// Append restart array
for (size_t i = 0; i < restarts_.size(); i++) {
PutFixed32(&buffer_, restarts_[i]);
}
PutFixed32(&buffer_, restarts_.size());
finished_ = true;
return Slice(buffer_);
}
void BlockBuilder::Add(const Slice& key, const Slice& value) {
Slice last_key_piece(last_key_);
assert(!finished_);
assert(counter_ <= options_->block_restart_interval);
assert(buffer_.empty() // No values yet?
|| options_->comparator->Compare(key, last_key_piece) > 0);
size_t shared = 0;
if (counter_ < options_->block_restart_interval) {
// See how much sharing to do with previous string
const size_t min_length = std::min(last_key_piece.size(), key.size());
while ((shared < min_length) && (last_key_piece[shared] == key[shared])) {
shared++;
}
} else {
// Restart compression
restarts_.push_back(buffer_.size());
counter_ = 0;
}
const size_t non_shared = key.size() - shared;
// Add "<shared><non_shared><value_size>" to buffer_
PutVarint32(&buffer_, shared);
PutVarint32(&buffer_, non_shared);
PutVarint32(&buffer_, value.size());
// Add string delta to buffer_ followed by value
buffer_.append(key.data() + shared, non_shared);
buffer_.append(value.data(), value.size());
// Update state
last_key_.resize(shared);
last_key_.append(key.data() + shared, non_shared);
assert(Slice(last_key_) == key);
counter_++;
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_
#define STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_
#include <vector>
#include <stdint.h>
#include "leveldb/slice.h"
namespace leveldb {
struct Options;
class BlockBuilder {
public:
explicit BlockBuilder(const Options* options);
// Reset the contents as if the BlockBuilder was just constructed.
void Reset();
// REQUIRES: Finish() has not been callled since the last call to Reset().
// REQUIRES: key is larger than any previously added key
void Add(const Slice& key, const Slice& value);
// Finish building the block and return a slice that refers to the
// block contents. The returned slice will remain valid for the
// lifetime of this builder or until Reset() is called.
Slice Finish();
// Returns an estimate of the current (uncompressed) size of the block
// we are building.
size_t CurrentSizeEstimate() const;
// Return true iff no entries have been added since the last Reset()
bool empty() const {
return buffer_.empty();
}
private:
const Options* options_;
std::string buffer_; // Destination buffer
std::vector<uint32_t> restarts_; // Restart points
int counter_; // Number of entries emitted since restart
bool finished_; // Has Finish() been called?
std::string last_key_;
// No copying allowed
BlockBuilder(const BlockBuilder&);
void operator=(const BlockBuilder&);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_

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// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/filter_block.h"
#include "leveldb/filter_policy.h"
#include "util/coding.h"
namespace leveldb {
// See doc/table_format.txt for an explanation of the filter block format.
// Generate new filter every 2KB of data
static const size_t kFilterBaseLg = 11;
static const size_t kFilterBase = 1 << kFilterBaseLg;
FilterBlockBuilder::FilterBlockBuilder(const FilterPolicy* policy)
: policy_(policy) {
}
void FilterBlockBuilder::StartBlock(uint64_t block_offset) {
uint64_t filter_index = (block_offset / kFilterBase);
assert(filter_index >= filter_offsets_.size());
while (filter_index > filter_offsets_.size()) {
GenerateFilter();
}
}
void FilterBlockBuilder::AddKey(const Slice& key) {
Slice k = key;
start_.push_back(keys_.size());
keys_.append(k.data(), k.size());
}
Slice FilterBlockBuilder::Finish() {
if (!start_.empty()) {
GenerateFilter();
}
// Append array of per-filter offsets
const uint32_t array_offset = result_.size();
for (size_t i = 0; i < filter_offsets_.size(); i++) {
PutFixed32(&result_, filter_offsets_[i]);
}
PutFixed32(&result_, array_offset);
result_.push_back(kFilterBaseLg); // Save encoding parameter in result
return Slice(result_);
}
void FilterBlockBuilder::GenerateFilter() {
const size_t num_keys = start_.size();
if (num_keys == 0) {
// Fast path if there are no keys for this filter
filter_offsets_.push_back(result_.size());
return;
}
// Make list of keys from flattened key structure
start_.push_back(keys_.size()); // Simplify length computation
tmp_keys_.resize(num_keys);
for (size_t i = 0; i < num_keys; i++) {
const char* base = keys_.data() + start_[i];
size_t length = start_[i+1] - start_[i];
tmp_keys_[i] = Slice(base, length);
}
// Generate filter for current set of keys and append to result_.
filter_offsets_.push_back(result_.size());
policy_->CreateFilter(&tmp_keys_[0], num_keys, &result_);
tmp_keys_.clear();
keys_.clear();
start_.clear();
}
FilterBlockReader::FilterBlockReader(const FilterPolicy* policy,
const Slice& contents)
: policy_(policy),
data_(NULL),
offset_(NULL),
num_(0),
base_lg_(0) {
size_t n = contents.size();
if (n < 5) return; // 1 byte for base_lg_ and 4 for start of offset array
base_lg_ = contents[n-1];
uint32_t last_word = DecodeFixed32(contents.data() + n - 5);
if (last_word > n - 5) return;
data_ = contents.data();
offset_ = data_ + last_word;
num_ = (n - 5 - last_word) / 4;
}
bool FilterBlockReader::KeyMayMatch(uint64_t block_offset, const Slice& key) {
uint64_t index = block_offset >> base_lg_;
if (index < num_) {
uint32_t start = DecodeFixed32(offset_ + index*4);
uint32_t limit = DecodeFixed32(offset_ + index*4 + 4);
if (start <= limit && limit <= (offset_ - data_)) {
Slice filter = Slice(data_ + start, limit - start);
return policy_->KeyMayMatch(key, filter);
} else if (start == limit) {
// Empty filters do not match any keys
return false;
}
}
return true; // Errors are treated as potential matches
}
}

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// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// A filter block is stored near the end of a Table file. It contains
// filters (e.g., bloom filters) for all data blocks in the table combined
// into a single filter block.
#ifndef STORAGE_LEVELDB_TABLE_FILTER_BLOCK_H_
#define STORAGE_LEVELDB_TABLE_FILTER_BLOCK_H_
#include <stddef.h>
#include <stdint.h>
#include <string>
#include <vector>
#include "leveldb/slice.h"
#include "util/hash.h"
namespace leveldb {
class FilterPolicy;
// A FilterBlockBuilder is used to construct all of the filters for a
// particular Table. It generates a single string which is stored as
// a special block in the Table.
//
// The sequence of calls to FilterBlockBuilder must match the regexp:
// (StartBlock AddKey*)* Finish
class FilterBlockBuilder {
public:
explicit FilterBlockBuilder(const FilterPolicy*);
void StartBlock(uint64_t block_offset);
void AddKey(const Slice& key);
Slice Finish();
private:
void GenerateFilter();
const FilterPolicy* policy_;
std::string keys_; // Flattened key contents
std::vector<size_t> start_; // Starting index in keys_ of each key
std::string result_; // Filter data computed so far
std::vector<Slice> tmp_keys_; // policy_->CreateFilter() argument
std::vector<uint32_t> filter_offsets_;
// No copying allowed
FilterBlockBuilder(const FilterBlockBuilder&);
void operator=(const FilterBlockBuilder&);
};
class FilterBlockReader {
public:
// REQUIRES: "contents" and *policy must stay live while *this is live.
FilterBlockReader(const FilterPolicy* policy, const Slice& contents);
bool KeyMayMatch(uint64_t block_offset, const Slice& key);
private:
const FilterPolicy* policy_;
const char* data_; // Pointer to filter data (at block-start)
const char* offset_; // Pointer to beginning of offset array (at block-end)
size_t num_; // Number of entries in offset array
size_t base_lg_; // Encoding parameter (see kFilterBaseLg in .cc file)
};
}
#endif // STORAGE_LEVELDB_TABLE_FILTER_BLOCK_H_

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// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/filter_block.h"
#include "leveldb/filter_policy.h"
#include "util/coding.h"
#include "util/hash.h"
#include "util/logging.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace leveldb {
// For testing: emit an array with one hash value per key
class TestHashFilter : public FilterPolicy {
public:
virtual const char* Name() const {
return "TestHashFilter";
}
virtual void CreateFilter(const Slice* keys, int n, std::string* dst) const {
for (int i = 0; i < n; i++) {
uint32_t h = Hash(keys[i].data(), keys[i].size(), 1);
PutFixed32(dst, h);
}
}
virtual bool KeyMayMatch(const Slice& key, const Slice& filter) const {
uint32_t h = Hash(key.data(), key.size(), 1);
for (int i = 0; i + 4 <= filter.size(); i += 4) {
if (h == DecodeFixed32(filter.data() + i)) {
return true;
}
}
return false;
}
};
class FilterBlockTest {
public:
TestHashFilter policy_;
};
TEST(FilterBlockTest, EmptyBuilder) {
FilterBlockBuilder builder(&policy_);
Slice block = builder.Finish();
ASSERT_EQ("\\x00\\x00\\x00\\x00\\x0b", EscapeString(block));
FilterBlockReader reader(&policy_, block);
ASSERT_TRUE(reader.KeyMayMatch(0, "foo"));
ASSERT_TRUE(reader.KeyMayMatch(100000, "foo"));
}
TEST(FilterBlockTest, SingleChunk) {
FilterBlockBuilder builder(&policy_);
builder.StartBlock(100);
builder.AddKey("foo");
builder.AddKey("bar");
builder.AddKey("box");
builder.StartBlock(200);
builder.AddKey("box");
builder.StartBlock(300);
builder.AddKey("hello");
Slice block = builder.Finish();
FilterBlockReader reader(&policy_, block);
ASSERT_TRUE(reader.KeyMayMatch(100, "foo"));
ASSERT_TRUE(reader.KeyMayMatch(100, "bar"));
ASSERT_TRUE(reader.KeyMayMatch(100, "box"));
ASSERT_TRUE(reader.KeyMayMatch(100, "hello"));
ASSERT_TRUE(reader.KeyMayMatch(100, "foo"));
ASSERT_TRUE(! reader.KeyMayMatch(100, "missing"));
ASSERT_TRUE(! reader.KeyMayMatch(100, "other"));
}
TEST(FilterBlockTest, MultiChunk) {
FilterBlockBuilder builder(&policy_);
// First filter
builder.StartBlock(0);
builder.AddKey("foo");
builder.StartBlock(2000);
builder.AddKey("bar");
// Second filter
builder.StartBlock(3100);
builder.AddKey("box");
// Third filter is empty
// Last filter
builder.StartBlock(9000);
builder.AddKey("box");
builder.AddKey("hello");
Slice block = builder.Finish();
FilterBlockReader reader(&policy_, block);
// Check first filter
ASSERT_TRUE(reader.KeyMayMatch(0, "foo"));
ASSERT_TRUE(reader.KeyMayMatch(2000, "bar"));
ASSERT_TRUE(! reader.KeyMayMatch(0, "box"));
ASSERT_TRUE(! reader.KeyMayMatch(0, "hello"));
// Check second filter
ASSERT_TRUE(reader.KeyMayMatch(3100, "box"));
ASSERT_TRUE(! reader.KeyMayMatch(3100, "foo"));
ASSERT_TRUE(! reader.KeyMayMatch(3100, "bar"));
ASSERT_TRUE(! reader.KeyMayMatch(3100, "hello"));
// Check third filter (empty)
ASSERT_TRUE(! reader.KeyMayMatch(4100, "foo"));
ASSERT_TRUE(! reader.KeyMayMatch(4100, "bar"));
ASSERT_TRUE(! reader.KeyMayMatch(4100, "box"));
ASSERT_TRUE(! reader.KeyMayMatch(4100, "hello"));
// Check last filter
ASSERT_TRUE(reader.KeyMayMatch(9000, "box"));
ASSERT_TRUE(reader.KeyMayMatch(9000, "hello"));
ASSERT_TRUE(! reader.KeyMayMatch(9000, "foo"));
ASSERT_TRUE(! reader.KeyMayMatch(9000, "bar"));
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/format.h"
#include "leveldb/env.h"
#include "port/port.h"
#include "table/block.h"
#include "util/coding.h"
#include "util/crc32c.h"
namespace leveldb {
void BlockHandle::EncodeTo(std::string* dst) const {
// Sanity check that all fields have been set
assert(offset_ != ~static_cast<uint64_t>(0));
assert(size_ != ~static_cast<uint64_t>(0));
PutVarint64(dst, offset_);
PutVarint64(dst, size_);
}
Status BlockHandle::DecodeFrom(Slice* input) {
if (GetVarint64(input, &offset_) &&
GetVarint64(input, &size_)) {
return Status::OK();
} else {
return Status::Corruption("bad block handle");
}
}
void Footer::EncodeTo(std::string* dst) const {
#ifndef NDEBUG
const size_t original_size = dst->size();
#endif
metaindex_handle_.EncodeTo(dst);
index_handle_.EncodeTo(dst);
dst->resize(2 * BlockHandle::kMaxEncodedLength); // Padding
PutFixed32(dst, static_cast<uint32_t>(kTableMagicNumber & 0xffffffffu));
PutFixed32(dst, static_cast<uint32_t>(kTableMagicNumber >> 32));
assert(dst->size() == original_size + kEncodedLength);
}
Status Footer::DecodeFrom(Slice* input) {
const char* magic_ptr = input->data() + kEncodedLength - 8;
const uint32_t magic_lo = DecodeFixed32(magic_ptr);
const uint32_t magic_hi = DecodeFixed32(magic_ptr + 4);
const uint64_t magic = ((static_cast<uint64_t>(magic_hi) << 32) |
(static_cast<uint64_t>(magic_lo)));
if (magic != kTableMagicNumber) {
return Status::InvalidArgument("not an sstable (bad magic number)");
}
Status result = metaindex_handle_.DecodeFrom(input);
if (result.ok()) {
result = index_handle_.DecodeFrom(input);
}
if (result.ok()) {
// We skip over any leftover data (just padding for now) in "input"
const char* end = magic_ptr + 8;
*input = Slice(end, input->data() + input->size() - end);
}
return result;
}
Status ReadBlock(RandomAccessFile* file,
const ReadOptions& options,
const BlockHandle& handle,
BlockContents* result) {
result->data = Slice();
result->cachable = false;
result->heap_allocated = false;
// Read the block contents as well as the type/crc footer.
// See table_builder.cc for the code that built this structure.
size_t n = static_cast<size_t>(handle.size());
char* buf = new char[n + kBlockTrailerSize];
Slice contents;
Status s = file->Read(handle.offset(), n + kBlockTrailerSize, &contents, buf);
if (!s.ok()) {
delete[] buf;
return s;
}
if (contents.size() != n + kBlockTrailerSize) {
delete[] buf;
return Status::Corruption("truncated block read");
}
// Check the crc of the type and the block contents
const char* data = contents.data(); // Pointer to where Read put the data
if (options.verify_checksums) {
const uint32_t crc = crc32c::Unmask(DecodeFixed32(data + n + 1));
const uint32_t actual = crc32c::Value(data, n + 1);
if (actual != crc) {
delete[] buf;
s = Status::Corruption("block checksum mismatch");
return s;
}
}
switch (data[n]) {
case kNoCompression:
if (data != buf) {
// File implementation gave us pointer to some other data.
// Use it directly under the assumption that it will be live
// while the file is open.
delete[] buf;
result->data = Slice(data, n);
result->heap_allocated = false;
result->cachable = false; // Do not double-cache
} else {
result->data = Slice(buf, n);
result->heap_allocated = true;
result->cachable = true;
}
// Ok
break;
case kSnappyCompression: {
size_t ulength = 0;
if (!port::Snappy_GetUncompressedLength(data, n, &ulength)) {
delete[] buf;
return Status::Corruption("corrupted compressed block contents");
}
char* ubuf = new char[ulength];
if (!port::Snappy_Uncompress(data, n, ubuf)) {
delete[] buf;
delete[] ubuf;
return Status::Corruption("corrupted compressed block contents");
}
delete[] buf;
result->data = Slice(ubuf, ulength);
result->heap_allocated = true;
result->cachable = true;
break;
}
default:
delete[] buf;
return Status::Corruption("bad block type");
}
return Status::OK();
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_TABLE_FORMAT_H_
#define STORAGE_LEVELDB_TABLE_FORMAT_H_
#include <string>
#include <stdint.h>
#include "leveldb/slice.h"
#include "leveldb/status.h"
#include "leveldb/table_builder.h"
namespace leveldb {
class Block;
class RandomAccessFile;
struct ReadOptions;
// BlockHandle is a pointer to the extent of a file that stores a data
// block or a meta block.
class BlockHandle {
public:
BlockHandle();
// The offset of the block in the file.
uint64_t offset() const { return offset_; }
void set_offset(uint64_t offset) { offset_ = offset; }
// The size of the stored block
uint64_t size() const { return size_; }
void set_size(uint64_t size) { size_ = size; }
void EncodeTo(std::string* dst) const;
Status DecodeFrom(Slice* input);
// Maximum encoding length of a BlockHandle
enum { kMaxEncodedLength = 10 + 10 };
private:
uint64_t offset_;
uint64_t size_;
};
// Footer encapsulates the fixed information stored at the tail
// end of every table file.
class Footer {
public:
Footer() { }
// The block handle for the metaindex block of the table
const BlockHandle& metaindex_handle() const { return metaindex_handle_; }
void set_metaindex_handle(const BlockHandle& h) { metaindex_handle_ = h; }
// The block handle for the index block of the table
const BlockHandle& index_handle() const {
return index_handle_;
}
void set_index_handle(const BlockHandle& h) {
index_handle_ = h;
}
void EncodeTo(std::string* dst) const;
Status DecodeFrom(Slice* input);
// Encoded length of a Footer. Note that the serialization of a
// Footer will always occupy exactly this many bytes. It consists
// of two block handles and a magic number.
enum {
kEncodedLength = 2*BlockHandle::kMaxEncodedLength + 8
};
private:
BlockHandle metaindex_handle_;
BlockHandle index_handle_;
};
// kTableMagicNumber was picked by running
// echo http://code.google.com/p/leveldb/ | sha1sum
// and taking the leading 64 bits.
static const uint64_t kTableMagicNumber = 0xdb4775248b80fb57ull;
// 1-byte type + 32-bit crc
static const size_t kBlockTrailerSize = 5;
struct BlockContents {
Slice data; // Actual contents of data
bool cachable; // True iff data can be cached
bool heap_allocated; // True iff caller should delete[] data.data()
};
// Read the block identified by "handle" from "file". On failure
// return non-OK. On success fill *result and return OK.
extern Status ReadBlock(RandomAccessFile* file,
const ReadOptions& options,
const BlockHandle& handle,
BlockContents* result);
// Implementation details follow. Clients should ignore,
inline BlockHandle::BlockHandle()
: offset_(~static_cast<uint64_t>(0)),
size_(~static_cast<uint64_t>(0)) {
}
} // namespace leveldb
#endif // STORAGE_LEVELDB_TABLE_FORMAT_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "leveldb/iterator.h"
namespace leveldb {
Iterator::Iterator() {
cleanup_.function = NULL;
cleanup_.next = NULL;
}
Iterator::~Iterator() {
if (cleanup_.function != NULL) {
(*cleanup_.function)(cleanup_.arg1, cleanup_.arg2);
for (Cleanup* c = cleanup_.next; c != NULL; ) {
(*c->function)(c->arg1, c->arg2);
Cleanup* next = c->next;
delete c;
c = next;
}
}
}
void Iterator::RegisterCleanup(CleanupFunction func, void* arg1, void* arg2) {
assert(func != NULL);
Cleanup* c;
if (cleanup_.function == NULL) {
c = &cleanup_;
} else {
c = new Cleanup;
c->next = cleanup_.next;
cleanup_.next = c;
}
c->function = func;
c->arg1 = arg1;
c->arg2 = arg2;
}
namespace {
class EmptyIterator : public Iterator {
public:
EmptyIterator(const Status& s) : status_(s) { }
virtual bool Valid() const { return false; }
virtual void Seek(const Slice& target) { }
virtual void SeekToFirst() { }
virtual void SeekToLast() { }
virtual void Next() { assert(false); }
virtual void Prev() { assert(false); }
Slice key() const { assert(false); return Slice(); }
Slice value() const { assert(false); return Slice(); }
virtual Status status() const { return status_; }
private:
Status status_;
};
} // namespace
Iterator* NewEmptyIterator() {
return new EmptyIterator(Status::OK());
}
Iterator* NewErrorIterator(const Status& status) {
return new EmptyIterator(status);
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_
#define STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_
namespace leveldb {
// A internal wrapper class with an interface similar to Iterator that
// caches the valid() and key() results for an underlying iterator.
// This can help avoid virtual function calls and also gives better
// cache locality.
class IteratorWrapper {
public:
IteratorWrapper(): iter_(NULL), valid_(false) { }
explicit IteratorWrapper(Iterator* iter): iter_(NULL) {
Set(iter);
}
~IteratorWrapper() { delete iter_; }
Iterator* iter() const { return iter_; }
// Takes ownership of "iter" and will delete it when destroyed, or
// when Set() is invoked again.
void Set(Iterator* iter) {
delete iter_;
iter_ = iter;
if (iter_ == NULL) {
valid_ = false;
} else {
Update();
}
}
// Iterator interface methods
bool Valid() const { return valid_; }
Slice key() const { assert(Valid()); return key_; }
Slice value() const { assert(Valid()); return iter_->value(); }
// Methods below require iter() != NULL
Status status() const { assert(iter_); return iter_->status(); }
void Next() { assert(iter_); iter_->Next(); Update(); }
void Prev() { assert(iter_); iter_->Prev(); Update(); }
void Seek(const Slice& k) { assert(iter_); iter_->Seek(k); Update(); }
void SeekToFirst() { assert(iter_); iter_->SeekToFirst(); Update(); }
void SeekToLast() { assert(iter_); iter_->SeekToLast(); Update(); }
private:
void Update() {
valid_ = iter_->Valid();
if (valid_) {
key_ = iter_->key();
}
}
Iterator* iter_;
bool valid_;
Slice key_;
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/merger.h"
#include "leveldb/comparator.h"
#include "leveldb/iterator.h"
#include "table/iterator_wrapper.h"
namespace leveldb {
namespace {
class MergingIterator : public Iterator {
public:
MergingIterator(const Comparator* comparator, Iterator** children, int n)
: comparator_(comparator),
children_(new IteratorWrapper[n]),
n_(n),
current_(NULL),
direction_(kForward) {
for (int i = 0; i < n; i++) {
children_[i].Set(children[i]);
}
}
virtual ~MergingIterator() {
delete[] children_;
}
virtual bool Valid() const {
return (current_ != NULL);
}
virtual void SeekToFirst() {
for (int i = 0; i < n_; i++) {
children_[i].SeekToFirst();
}
FindSmallest();
direction_ = kForward;
}
virtual void SeekToLast() {
for (int i = 0; i < n_; i++) {
children_[i].SeekToLast();
}
FindLargest();
direction_ = kReverse;
}
virtual void Seek(const Slice& target) {
for (int i = 0; i < n_; i++) {
children_[i].Seek(target);
}
FindSmallest();
direction_ = kForward;
}
virtual void Next() {
assert(Valid());
// Ensure that all children are positioned after key().
// If we are moving in the forward direction, it is already
// true for all of the non-current_ children since current_ is
// the smallest child and key() == current_->key(). Otherwise,
// we explicitly position the non-current_ children.
if (direction_ != kForward) {
for (int i = 0; i < n_; i++) {
IteratorWrapper* child = &children_[i];
if (child != current_) {
child->Seek(key());
if (child->Valid() &&
comparator_->Compare(key(), child->key()) == 0) {
child->Next();
}
}
}
direction_ = kForward;
}
current_->Next();
FindSmallest();
}
virtual void Prev() {
assert(Valid());
// Ensure that all children are positioned before key().
// If we are moving in the reverse direction, it is already
// true for all of the non-current_ children since current_ is
// the largest child and key() == current_->key(). Otherwise,
// we explicitly position the non-current_ children.
if (direction_ != kReverse) {
for (int i = 0; i < n_; i++) {
IteratorWrapper* child = &children_[i];
if (child != current_) {
child->Seek(key());
if (child->Valid()) {
// Child is at first entry >= key(). Step back one to be < key()
child->Prev();
} else {
// Child has no entries >= key(). Position at last entry.
child->SeekToLast();
}
}
}
direction_ = kReverse;
}
current_->Prev();
FindLargest();
}
virtual Slice key() const {
assert(Valid());
return current_->key();
}
virtual Slice value() const {
assert(Valid());
return current_->value();
}
virtual Status status() const {
Status status;
for (int i = 0; i < n_; i++) {
status = children_[i].status();
if (!status.ok()) {
break;
}
}
return status;
}
private:
void FindSmallest();
void FindLargest();
// We might want to use a heap in case there are lots of children.
// For now we use a simple array since we expect a very small number
// of children in leveldb.
const Comparator* comparator_;
IteratorWrapper* children_;
int n_;
IteratorWrapper* current_;
// Which direction is the iterator moving?
enum Direction {
kForward,
kReverse
};
Direction direction_;
};
void MergingIterator::FindSmallest() {
IteratorWrapper* smallest = NULL;
for (int i = 0; i < n_; i++) {
IteratorWrapper* child = &children_[i];
if (child->Valid()) {
if (smallest == NULL) {
smallest = child;
} else if (comparator_->Compare(child->key(), smallest->key()) < 0) {
smallest = child;
}
}
}
current_ = smallest;
}
void MergingIterator::FindLargest() {
IteratorWrapper* largest = NULL;
for (int i = n_-1; i >= 0; i--) {
IteratorWrapper* child = &children_[i];
if (child->Valid()) {
if (largest == NULL) {
largest = child;
} else if (comparator_->Compare(child->key(), largest->key()) > 0) {
largest = child;
}
}
}
current_ = largest;
}
} // namespace
Iterator* NewMergingIterator(const Comparator* cmp, Iterator** list, int n) {
assert(n >= 0);
if (n == 0) {
return NewEmptyIterator();
} else if (n == 1) {
return list[0];
} else {
return new MergingIterator(cmp, list, n);
}
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_TABLE_MERGER_H_
#define STORAGE_LEVELDB_TABLE_MERGER_H_
namespace leveldb {
class Comparator;
class Iterator;
// Return an iterator that provided the union of the data in
// children[0,n-1]. Takes ownership of the child iterators and
// will delete them when the result iterator is deleted.
//
// The result does no duplicate suppression. I.e., if a particular
// key is present in K child iterators, it will be yielded K times.
//
// REQUIRES: n >= 0
extern Iterator* NewMergingIterator(
const Comparator* comparator, Iterator** children, int n);
} // namespace leveldb
#endif // STORAGE_LEVELDB_TABLE_MERGER_H_

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "leveldb/table.h"
#include "leveldb/cache.h"
#include "leveldb/comparator.h"
#include "leveldb/env.h"
#include "leveldb/filter_policy.h"
#include "leveldb/options.h"
#include "table/block.h"
#include "table/filter_block.h"
#include "table/format.h"
#include "table/two_level_iterator.h"
#include "util/coding.h"
namespace leveldb {
struct Table::Rep {
~Rep() {
delete filter;
delete [] filter_data;
delete index_block;
}
Options options;
Status status;
RandomAccessFile* file;
uint64_t cache_id;
FilterBlockReader* filter;
const char* filter_data;
BlockHandle metaindex_handle; // Handle to metaindex_block: saved from footer
Block* index_block;
};
Status Table::Open(const Options& options,
RandomAccessFile* file,
uint64_t size,
Table** table) {
*table = NULL;
if (size < Footer::kEncodedLength) {
return Status::InvalidArgument("file is too short to be an sstable");
}
char footer_space[Footer::kEncodedLength];
Slice footer_input;
Status s = file->Read(size - Footer::kEncodedLength, Footer::kEncodedLength,
&footer_input, footer_space);
if (!s.ok()) return s;
Footer footer;
s = footer.DecodeFrom(&footer_input);
if (!s.ok()) return s;
// Read the index block
BlockContents contents;
Block* index_block = NULL;
if (s.ok()) {
s = ReadBlock(file, ReadOptions(), footer.index_handle(), &contents);
if (s.ok()) {
index_block = new Block(contents);
}
}
if (s.ok()) {
// We've successfully read the footer and the index block: we're
// ready to serve requests.
Rep* rep = new Table::Rep;
rep->options = options;
rep->file = file;
rep->metaindex_handle = footer.metaindex_handle();
rep->index_block = index_block;
rep->cache_id = (options.block_cache ? options.block_cache->NewId() : 0);
rep->filter_data = NULL;
rep->filter = NULL;
*table = new Table(rep);
(*table)->ReadMeta(footer);
} else {
if (index_block) delete index_block;
}
return s;
}
void Table::ReadMeta(const Footer& footer) {
if (rep_->options.filter_policy == NULL) {
return; // Do not need any metadata
}
// TODO(sanjay): Skip this if footer.metaindex_handle() size indicates
// it is an empty block.
ReadOptions opt;
BlockContents contents;
if (!ReadBlock(rep_->file, opt, footer.metaindex_handle(), &contents).ok()) {
// Do not propagate errors since meta info is not needed for operation
return;
}
Block* meta = new Block(contents);
Iterator* iter = meta->NewIterator(BytewiseComparator());
std::string key = "filter.";
key.append(rep_->options.filter_policy->Name());
iter->Seek(key);
if (iter->Valid() && iter->key() == Slice(key)) {
ReadFilter(iter->value());
}
delete iter;
delete meta;
}
void Table::ReadFilter(const Slice& filter_handle_value) {
Slice v = filter_handle_value;
BlockHandle filter_handle;
if (!filter_handle.DecodeFrom(&v).ok()) {
return;
}
// We might want to unify with ReadBlock() if we start
// requiring checksum verification in Table::Open.
ReadOptions opt;
BlockContents block;
if (!ReadBlock(rep_->file, opt, filter_handle, &block).ok()) {
return;
}
if (block.heap_allocated) {
rep_->filter_data = block.data.data(); // Will need to delete later
}
rep_->filter = new FilterBlockReader(rep_->options.filter_policy, block.data);
}
Table::~Table() {
delete rep_;
}
static void DeleteBlock(void* arg, void* ignored) {
delete reinterpret_cast<Block*>(arg);
}
static void DeleteCachedBlock(const Slice& key, void* value) {
Block* block = reinterpret_cast<Block*>(value);
delete block;
}
static void ReleaseBlock(void* arg, void* h) {
Cache* cache = reinterpret_cast<Cache*>(arg);
Cache::Handle* handle = reinterpret_cast<Cache::Handle*>(h);
cache->Release(handle);
}
// Convert an index iterator value (i.e., an encoded BlockHandle)
// into an iterator over the contents of the corresponding block.
Iterator* Table::BlockReader(void* arg,
const ReadOptions& options,
const Slice& index_value) {
Table* table = reinterpret_cast<Table*>(arg);
Cache* block_cache = table->rep_->options.block_cache;
Block* block = NULL;
Cache::Handle* cache_handle = NULL;
BlockHandle handle;
Slice input = index_value;
Status s = handle.DecodeFrom(&input);
// We intentionally allow extra stuff in index_value so that we
// can add more features in the future.
if (s.ok()) {
BlockContents contents;
if (block_cache != NULL) {
char cache_key_buffer[16];
EncodeFixed64(cache_key_buffer, table->rep_->cache_id);
EncodeFixed64(cache_key_buffer+8, handle.offset());
Slice key(cache_key_buffer, sizeof(cache_key_buffer));
cache_handle = block_cache->Lookup(key);
if (cache_handle != NULL) {
block = reinterpret_cast<Block*>(block_cache->Value(cache_handle));
} else {
s = ReadBlock(table->rep_->file, options, handle, &contents);
if (s.ok()) {
block = new Block(contents);
if (contents.cachable && options.fill_cache) {
cache_handle = block_cache->Insert(
key, block, block->size(), &DeleteCachedBlock);
}
}
}
} else {
s = ReadBlock(table->rep_->file, options, handle, &contents);
if (s.ok()) {
block = new Block(contents);
}
}
}
Iterator* iter;
if (block != NULL) {
iter = block->NewIterator(table->rep_->options.comparator);
if (cache_handle == NULL) {
iter->RegisterCleanup(&DeleteBlock, block, NULL);
} else {
iter->RegisterCleanup(&ReleaseBlock, block_cache, cache_handle);
}
} else {
iter = NewErrorIterator(s);
}
return iter;
}
Iterator* Table::NewIterator(const ReadOptions& options) const {
return NewTwoLevelIterator(
rep_->index_block->NewIterator(rep_->options.comparator),
&Table::BlockReader, const_cast<Table*>(this), options);
}
Status Table::InternalGet(const ReadOptions& options, const Slice& k,
void* arg,
void (*saver)(void*, const Slice&, const Slice&)) {
Status s;
Iterator* iiter = rep_->index_block->NewIterator(rep_->options.comparator);
iiter->Seek(k);
if (iiter->Valid()) {
Slice handle_value = iiter->value();
FilterBlockReader* filter = rep_->filter;
BlockHandle handle;
if (filter != NULL &&
handle.DecodeFrom(&handle_value).ok() &&
!filter->KeyMayMatch(handle.offset(), k)) {
// Not found
} else {
Slice handle = iiter->value();
Iterator* block_iter = BlockReader(this, options, iiter->value());
block_iter->Seek(k);
if (block_iter->Valid()) {
(*saver)(arg, block_iter->key(), block_iter->value());
}
s = block_iter->status();
delete block_iter;
}
}
if (s.ok()) {
s = iiter->status();
}
delete iiter;
return s;
}
uint64_t Table::ApproximateOffsetOf(const Slice& key) const {
Iterator* index_iter =
rep_->index_block->NewIterator(rep_->options.comparator);
index_iter->Seek(key);
uint64_t result;
if (index_iter->Valid()) {
BlockHandle handle;
Slice input = index_iter->value();
Status s = handle.DecodeFrom(&input);
if (s.ok()) {
result = handle.offset();
} else {
// Strange: we can't decode the block handle in the index block.
// We'll just return the offset of the metaindex block, which is
// close to the whole file size for this case.
result = rep_->metaindex_handle.offset();
}
} else {
// key is past the last key in the file. Approximate the offset
// by returning the offset of the metaindex block (which is
// right near the end of the file).
result = rep_->metaindex_handle.offset();
}
delete index_iter;
return result;
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "leveldb/table_builder.h"
#include <assert.h>
#include "leveldb/comparator.h"
#include "leveldb/env.h"
#include "leveldb/filter_policy.h"
#include "leveldb/options.h"
#include "table/block_builder.h"
#include "table/filter_block.h"
#include "table/format.h"
#include "util/coding.h"
#include "util/crc32c.h"
namespace leveldb {
struct TableBuilder::Rep {
Options options;
Options index_block_options;
WritableFile* file;
uint64_t offset;
Status status;
BlockBuilder data_block;
BlockBuilder index_block;
std::string last_key;
int64_t num_entries;
bool closed; // Either Finish() or Abandon() has been called.
FilterBlockBuilder* filter_block;
// We do not emit the index entry for a block until we have seen the
// first key for the next data block. This allows us to use shorter
// keys in the index block. For example, consider a block boundary
// between the keys "the quick brown fox" and "the who". We can use
// "the r" as the key for the index block entry since it is >= all
// entries in the first block and < all entries in subsequent
// blocks.
//
// Invariant: r->pending_index_entry is true only if data_block is empty.
bool pending_index_entry;
BlockHandle pending_handle; // Handle to add to index block
std::string compressed_output;
Rep(const Options& opt, WritableFile* f)
: options(opt),
index_block_options(opt),
file(f),
offset(0),
data_block(&options),
index_block(&index_block_options),
num_entries(0),
closed(false),
filter_block(opt.filter_policy == NULL ? NULL
: new FilterBlockBuilder(opt.filter_policy)),
pending_index_entry(false) {
index_block_options.block_restart_interval = 1;
}
};
TableBuilder::TableBuilder(const Options& options, WritableFile* file)
: rep_(new Rep(options, file)) {
if (rep_->filter_block != NULL) {
rep_->filter_block->StartBlock(0);
}
}
TableBuilder::~TableBuilder() {
assert(rep_->closed); // Catch errors where caller forgot to call Finish()
delete rep_->filter_block;
delete rep_;
}
Status TableBuilder::ChangeOptions(const Options& options) {
// Note: if more fields are added to Options, update
// this function to catch changes that should not be allowed to
// change in the middle of building a Table.
if (options.comparator != rep_->options.comparator) {
return Status::InvalidArgument("changing comparator while building table");
}
// Note that any live BlockBuilders point to rep_->options and therefore
// will automatically pick up the updated options.
rep_->options = options;
rep_->index_block_options = options;
rep_->index_block_options.block_restart_interval = 1;
return Status::OK();
}
void TableBuilder::Add(const Slice& key, const Slice& value) {
Rep* r = rep_;
assert(!r->closed);
if (!ok()) return;
if (r->num_entries > 0) {
assert(r->options.comparator->Compare(key, Slice(r->last_key)) > 0);
}
if (r->pending_index_entry) {
assert(r->data_block.empty());
r->options.comparator->FindShortestSeparator(&r->last_key, key);
std::string handle_encoding;
r->pending_handle.EncodeTo(&handle_encoding);
r->index_block.Add(r->last_key, Slice(handle_encoding));
r->pending_index_entry = false;
}
if (r->filter_block != NULL) {
r->filter_block->AddKey(key);
}
r->last_key.assign(key.data(), key.size());
r->num_entries++;
r->data_block.Add(key, value);
const size_t estimated_block_size = r->data_block.CurrentSizeEstimate();
if (estimated_block_size >= r->options.block_size) {
Flush();
}
}
void TableBuilder::Flush() {
Rep* r = rep_;
assert(!r->closed);
if (!ok()) return;
if (r->data_block.empty()) return;
assert(!r->pending_index_entry);
WriteBlock(&r->data_block, &r->pending_handle);
if (ok()) {
r->pending_index_entry = true;
r->status = r->file->Flush();
}
if (r->filter_block != NULL) {
r->filter_block->StartBlock(r->offset);
}
}
void TableBuilder::WriteBlock(BlockBuilder* block, BlockHandle* handle) {
// File format contains a sequence of blocks where each block has:
// block_data: uint8[n]
// type: uint8
// crc: uint32
assert(ok());
Rep* r = rep_;
Slice raw = block->Finish();
Slice block_contents;
CompressionType type = r->options.compression;
// TODO(postrelease): Support more compression options: zlib?
switch (type) {
case kNoCompression:
block_contents = raw;
break;
case kSnappyCompression: {
std::string* compressed = &r->compressed_output;
if (port::Snappy_Compress(raw.data(), raw.size(), compressed) &&
compressed->size() < raw.size() - (raw.size() / 8u)) {
block_contents = *compressed;
} else {
// Snappy not supported, or compressed less than 12.5%, so just
// store uncompressed form
block_contents = raw;
type = kNoCompression;
}
break;
}
}
WriteRawBlock(block_contents, type, handle);
r->compressed_output.clear();
block->Reset();
}
void TableBuilder::WriteRawBlock(const Slice& block_contents,
CompressionType type,
BlockHandle* handle) {
Rep* r = rep_;
handle->set_offset(r->offset);
handle->set_size(block_contents.size());
r->status = r->file->Append(block_contents);
if (r->status.ok()) {
char trailer[kBlockTrailerSize];
trailer[0] = type;
uint32_t crc = crc32c::Value(block_contents.data(), block_contents.size());
crc = crc32c::Extend(crc, trailer, 1); // Extend crc to cover block type
EncodeFixed32(trailer+1, crc32c::Mask(crc));
r->status = r->file->Append(Slice(trailer, kBlockTrailerSize));
if (r->status.ok()) {
r->offset += block_contents.size() + kBlockTrailerSize;
}
}
}
Status TableBuilder::status() const {
return rep_->status;
}
Status TableBuilder::Finish() {
Rep* r = rep_;
Flush();
assert(!r->closed);
r->closed = true;
BlockHandle filter_block_handle, metaindex_block_handle, index_block_handle;
// Write filter block
if (ok() && r->filter_block != NULL) {
WriteRawBlock(r->filter_block->Finish(), kNoCompression,
&filter_block_handle);
}
// Write metaindex block
if (ok()) {
BlockBuilder meta_index_block(&r->options);
if (r->filter_block != NULL) {
// Add mapping from "filter.Name" to location of filter data
std::string key = "filter.";
key.append(r->options.filter_policy->Name());
std::string handle_encoding;
filter_block_handle.EncodeTo(&handle_encoding);
meta_index_block.Add(key, handle_encoding);
}
// TODO(postrelease): Add stats and other meta blocks
WriteBlock(&meta_index_block, &metaindex_block_handle);
}
// Write index block
if (ok()) {
if (r->pending_index_entry) {
r->options.comparator->FindShortSuccessor(&r->last_key);
std::string handle_encoding;
r->pending_handle.EncodeTo(&handle_encoding);
r->index_block.Add(r->last_key, Slice(handle_encoding));
r->pending_index_entry = false;
}
WriteBlock(&r->index_block, &index_block_handle);
}
// Write footer
if (ok()) {
Footer footer;
footer.set_metaindex_handle(metaindex_block_handle);
footer.set_index_handle(index_block_handle);
std::string footer_encoding;
footer.EncodeTo(&footer_encoding);
r->status = r->file->Append(footer_encoding);
if (r->status.ok()) {
r->offset += footer_encoding.size();
}
}
return r->status;
}
void TableBuilder::Abandon() {
Rep* r = rep_;
assert(!r->closed);
r->closed = true;
}
uint64_t TableBuilder::NumEntries() const {
return rep_->num_entries;
}
uint64_t TableBuilder::FileSize() const {
return rep_->offset;
}
} // namespace leveldb

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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "leveldb/table.h"
#include <map>
#include <string>
#include "db/dbformat.h"
#include "db/memtable.h"
#include "db/write_batch_internal.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "leveldb/iterator.h"
#include "leveldb/table_builder.h"
#include "table/block.h"
#include "table/block_builder.h"
#include "table/format.h"
#include "util/random.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace leveldb {
// Return reverse of "key".
// Used to test non-lexicographic comparators.
static std::string Reverse(const Slice& key) {
std::string str(key.ToString());
std::string rev("");
for (std::string::reverse_iterator rit = str.rbegin();
rit != str.rend(); ++rit) {
rev.push_back(*rit);
}
return rev;
}
namespace {
class ReverseKeyComparator : public Comparator {
public:
virtual const char* Name() const {
return "leveldb.ReverseBytewiseComparator";
}
virtual int Compare(const Slice& a, const Slice& b) const {
return BytewiseComparator()->Compare(Reverse(a), Reverse(b));
}
virtual void FindShortestSeparator(
std::string* start,
const Slice& limit) const {
std::string s = Reverse(*start);
std::string l = Reverse(limit);
BytewiseComparator()->FindShortestSeparator(&s, l);
*start = Reverse(s);
}
virtual void FindShortSuccessor(std::string* key) const {
std::string s = Reverse(*key);
BytewiseComparator()->FindShortSuccessor(&s);
*key = Reverse(s);
}
};
} // namespace
static ReverseKeyComparator reverse_key_comparator;
static void Increment(const Comparator* cmp, std::string* key) {
if (cmp == BytewiseComparator()) {
key->push_back('\0');
} else {
assert(cmp == &reverse_key_comparator);
std::string rev = Reverse(*key);
rev.push_back('\0');
*key = Reverse(rev);
}
}
// An STL comparator that uses a Comparator
namespace {
struct STLLessThan {
const Comparator* cmp;
STLLessThan() : cmp(BytewiseComparator()) { }
STLLessThan(const Comparator* c) : cmp(c) { }
bool operator()(const std::string& a, const std::string& b) const {
return cmp->Compare(Slice(a), Slice(b)) < 0;
}
};
} // namespace
class StringSink: public WritableFile {
public:
~StringSink() { }
const std::string& contents() const { return contents_; }
virtual Status Close() { return Status::OK(); }
virtual Status Flush() { return Status::OK(); }
virtual Status Sync() { return Status::OK(); }
virtual Status Append(const Slice& data) {
contents_.append(data.data(), data.size());
return Status::OK();
}
private:
std::string contents_;
};
class StringSource: public RandomAccessFile {
public:
StringSource(const Slice& contents)
: contents_(contents.data(), contents.size()) {
}
virtual ~StringSource() { }
uint64_t Size() const { return contents_.size(); }
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const {
if (offset > contents_.size()) {
return Status::InvalidArgument("invalid Read offset");
}
if (offset + n > contents_.size()) {
n = contents_.size() - offset;
}
memcpy(scratch, &contents_[offset], n);
*result = Slice(scratch, n);
return Status::OK();
}
private:
std::string contents_;
};
typedef std::map<std::string, std::string, STLLessThan> KVMap;
// Helper class for tests to unify the interface between
// BlockBuilder/TableBuilder and Block/Table.
class Constructor {
public:
explicit Constructor(const Comparator* cmp) : data_(STLLessThan(cmp)) { }
virtual ~Constructor() { }
void Add(const std::string& key, const Slice& value) {
data_[key] = value.ToString();
}
// Finish constructing the data structure with all the keys that have
// been added so far. Returns the keys in sorted order in "*keys"
// and stores the key/value pairs in "*kvmap"
void Finish(const Options& options,
std::vector<std::string>* keys,
KVMap* kvmap) {
*kvmap = data_;
keys->clear();
for (KVMap::const_iterator it = data_.begin();
it != data_.end();
++it) {
keys->push_back(it->first);
}
data_.clear();
Status s = FinishImpl(options, *kvmap);
ASSERT_TRUE(s.ok()) << s.ToString();
}
// Construct the data structure from the data in "data"
virtual Status FinishImpl(const Options& options, const KVMap& data) = 0;
virtual Iterator* NewIterator() const = 0;
virtual const KVMap& data() { return data_; }
virtual DB* db() const { return NULL; } // Overridden in DBConstructor
private:
KVMap data_;
};
class BlockConstructor: public Constructor {
public:
explicit BlockConstructor(const Comparator* cmp)
: Constructor(cmp),
comparator_(cmp),
block_(NULL) { }
~BlockConstructor() {
delete block_;
}
virtual Status FinishImpl(const Options& options, const KVMap& data) {
delete block_;
block_ = NULL;
BlockBuilder builder(&options);
for (KVMap::const_iterator it = data.begin();
it != data.end();
++it) {
builder.Add(it->first, it->second);
}
// Open the block
data_ = builder.Finish().ToString();
BlockContents contents;
contents.data = data_;
contents.cachable = false;
contents.heap_allocated = false;
block_ = new Block(contents);
return Status::OK();
}
virtual Iterator* NewIterator() const {
return block_->NewIterator(comparator_);
}
private:
const Comparator* comparator_;
std::string data_;
Block* block_;
BlockConstructor();
};
class TableConstructor: public Constructor {
public:
TableConstructor(const Comparator* cmp)
: Constructor(cmp),
source_(NULL), table_(NULL) {
}
~TableConstructor() {
Reset();
}
virtual Status FinishImpl(const Options& options, const KVMap& data) {
Reset();
StringSink sink;
TableBuilder builder(options, &sink);
for (KVMap::const_iterator it = data.begin();
it != data.end();
++it) {
builder.Add(it->first, it->second);
ASSERT_TRUE(builder.status().ok());
}
Status s = builder.Finish();
ASSERT_TRUE(s.ok()) << s.ToString();
ASSERT_EQ(sink.contents().size(), builder.FileSize());
// Open the table
source_ = new StringSource(sink.contents());
Options table_options;
table_options.comparator = options.comparator;
return Table::Open(table_options, source_, sink.contents().size(), &table_);
}
virtual Iterator* NewIterator() const {
return table_->NewIterator(ReadOptions());
}
uint64_t ApproximateOffsetOf(const Slice& key) const {
return table_->ApproximateOffsetOf(key);
}
private:
void Reset() {
delete table_;
delete source_;
table_ = NULL;
source_ = NULL;
}
StringSource* source_;
Table* table_;
TableConstructor();
};
// A helper class that converts internal format keys into user keys
class KeyConvertingIterator: public Iterator {
public:
explicit KeyConvertingIterator(Iterator* iter) : iter_(iter) { }
virtual ~KeyConvertingIterator() { delete iter_; }
virtual bool Valid() const { return iter_->Valid(); }
virtual void Seek(const Slice& target) {
ParsedInternalKey ikey(target, kMaxSequenceNumber, kTypeValue);
std::string encoded;
AppendInternalKey(&encoded, ikey);
iter_->Seek(encoded);
}
virtual void SeekToFirst() { iter_->SeekToFirst(); }
virtual void SeekToLast() { iter_->SeekToLast(); }
virtual void Next() { iter_->Next(); }
virtual void Prev() { iter_->Prev(); }
virtual Slice key() const {
assert(Valid());
ParsedInternalKey key;
if (!ParseInternalKey(iter_->key(), &key)) {
status_ = Status::Corruption("malformed internal key");
return Slice("corrupted key");
}
return key.user_key;
}
virtual Slice value() const { return iter_->value(); }
virtual Status status() const {
return status_.ok() ? iter_->status() : status_;
}
private:
mutable Status status_;
Iterator* iter_;
// No copying allowed
KeyConvertingIterator(const KeyConvertingIterator&);
void operator=(const KeyConvertingIterator&);
};
class MemTableConstructor: public Constructor {
public:
explicit MemTableConstructor(const Comparator* cmp)
: Constructor(cmp),
internal_comparator_(cmp) {
memtable_ = new MemTable(internal_comparator_);
memtable_->Ref();
}
~MemTableConstructor() {
memtable_->Unref();
}
virtual Status FinishImpl(const Options& options, const KVMap& data) {
memtable_->Unref();
memtable_ = new MemTable(internal_comparator_);
memtable_->Ref();
int seq = 1;
for (KVMap::const_iterator it = data.begin();
it != data.end();
++it) {
memtable_->Add(seq, kTypeValue, it->first, it->second);
seq++;
}
return Status::OK();
}
virtual Iterator* NewIterator() const {
return new KeyConvertingIterator(memtable_->NewIterator());
}
private:
InternalKeyComparator internal_comparator_;
MemTable* memtable_;
};
class DBConstructor: public Constructor {
public:
explicit DBConstructor(const Comparator* cmp)
: Constructor(cmp),
comparator_(cmp) {
db_ = NULL;
NewDB();
}
~DBConstructor() {
delete db_;
}
virtual Status FinishImpl(const Options& options, const KVMap& data) {
delete db_;
db_ = NULL;
NewDB();
for (KVMap::const_iterator it = data.begin();
it != data.end();
++it) {
WriteBatch batch;
batch.Put(it->first, it->second);
ASSERT_TRUE(db_->Write(WriteOptions(), &batch).ok());
}
return Status::OK();
}
virtual Iterator* NewIterator() const {
return db_->NewIterator(ReadOptions());
}
virtual DB* db() const { return db_; }
private:
void NewDB() {
std::string name = test::TmpDir() + "/table_testdb";
Options options;
options.comparator = comparator_;
Status status = DestroyDB(name, options);
ASSERT_TRUE(status.ok()) << status.ToString();
options.create_if_missing = true;
options.error_if_exists = true;
options.write_buffer_size = 10000; // Something small to force merging
status = DB::Open(options, name, &db_);
ASSERT_TRUE(status.ok()) << status.ToString();
}
const Comparator* comparator_;
DB* db_;
};
enum TestType {
TABLE_TEST,
BLOCK_TEST,
MEMTABLE_TEST,
DB_TEST
};
struct TestArgs {
TestType type;
bool reverse_compare;
int restart_interval;
};
static const TestArgs kTestArgList[] = {
{ TABLE_TEST, false, 16 },
{ TABLE_TEST, false, 1 },
{ TABLE_TEST, false, 1024 },
{ TABLE_TEST, true, 16 },
{ TABLE_TEST, true, 1 },
{ TABLE_TEST, true, 1024 },
{ BLOCK_TEST, false, 16 },
{ BLOCK_TEST, false, 1 },
{ BLOCK_TEST, false, 1024 },
{ BLOCK_TEST, true, 16 },
{ BLOCK_TEST, true, 1 },
{ BLOCK_TEST, true, 1024 },
// Restart interval does not matter for memtables
{ MEMTABLE_TEST, false, 16 },
{ MEMTABLE_TEST, true, 16 },
// Do not bother with restart interval variations for DB
{ DB_TEST, false, 16 },
{ DB_TEST, true, 16 },
};
static const int kNumTestArgs = sizeof(kTestArgList) / sizeof(kTestArgList[0]);
class Harness {
public:
Harness() : constructor_(NULL) { }
void Init(const TestArgs& args) {
delete constructor_;
constructor_ = NULL;
options_ = Options();
options_.block_restart_interval = args.restart_interval;
// Use shorter block size for tests to exercise block boundary
// conditions more.
options_.block_size = 256;
if (args.reverse_compare) {
options_.comparator = &reverse_key_comparator;
}
switch (args.type) {
case TABLE_TEST:
constructor_ = new TableConstructor(options_.comparator);
break;
case BLOCK_TEST:
constructor_ = new BlockConstructor(options_.comparator);
break;
case MEMTABLE_TEST:
constructor_ = new MemTableConstructor(options_.comparator);
break;
case DB_TEST:
constructor_ = new DBConstructor(options_.comparator);
break;
}
}
~Harness() {
delete constructor_;
}
void Add(const std::string& key, const std::string& value) {
constructor_->Add(key, value);
}
void Test(Random* rnd) {
std::vector<std::string> keys;
KVMap data;
constructor_->Finish(options_, &keys, &data);
TestForwardScan(keys, data);
TestBackwardScan(keys, data);
TestRandomAccess(rnd, keys, data);
}
void TestForwardScan(const std::vector<std::string>& keys,
const KVMap& data) {
Iterator* iter = constructor_->NewIterator();
ASSERT_TRUE(!iter->Valid());
iter->SeekToFirst();
for (KVMap::const_iterator model_iter = data.begin();
model_iter != data.end();
++model_iter) {
ASSERT_EQ(ToString(data, model_iter), ToString(iter));
iter->Next();
}
ASSERT_TRUE(!iter->Valid());
delete iter;
}
void TestBackwardScan(const std::vector<std::string>& keys,
const KVMap& data) {
Iterator* iter = constructor_->NewIterator();
ASSERT_TRUE(!iter->Valid());
iter->SeekToLast();
for (KVMap::const_reverse_iterator model_iter = data.rbegin();
model_iter != data.rend();
++model_iter) {
ASSERT_EQ(ToString(data, model_iter), ToString(iter));
iter->Prev();
}
ASSERT_TRUE(!iter->Valid());
delete iter;
}
void TestRandomAccess(Random* rnd,
const std::vector<std::string>& keys,
const KVMap& data) {
static const bool kVerbose = false;
Iterator* iter = constructor_->NewIterator();
ASSERT_TRUE(!iter->Valid());
KVMap::const_iterator model_iter = data.begin();
if (kVerbose) fprintf(stderr, "---\n");
for (int i = 0; i < 200; i++) {
const int toss = rnd->Uniform(5);
switch (toss) {
case 0: {
if (iter->Valid()) {
if (kVerbose) fprintf(stderr, "Next\n");
iter->Next();
++model_iter;
ASSERT_EQ(ToString(data, model_iter), ToString(iter));
}
break;
}
case 1: {
if (kVerbose) fprintf(stderr, "SeekToFirst\n");
iter->SeekToFirst();
model_iter = data.begin();
ASSERT_EQ(ToString(data, model_iter), ToString(iter));
break;
}
case 2: {
std::string key = PickRandomKey(rnd, keys);
model_iter = data.lower_bound(key);
if (kVerbose) fprintf(stderr, "Seek '%s'\n",
EscapeString(key).c_str());
iter->Seek(Slice(key));
ASSERT_EQ(ToString(data, model_iter), ToString(iter));
break;
}
case 3: {
if (iter->Valid()) {
if (kVerbose) fprintf(stderr, "Prev\n");
iter->Prev();
if (model_iter == data.begin()) {
model_iter = data.end(); // Wrap around to invalid value
} else {
--model_iter;
}
ASSERT_EQ(ToString(data, model_iter), ToString(iter));
}
break;
}
case 4: {
if (kVerbose) fprintf(stderr, "SeekToLast\n");
iter->SeekToLast();
if (keys.empty()) {
model_iter = data.end();
} else {
std::string last = data.rbegin()->first;
model_iter = data.lower_bound(last);
}
ASSERT_EQ(ToString(data, model_iter), ToString(iter));
break;
}
}
}
delete iter;
}
std::string ToString(const KVMap& data, const KVMap::const_iterator& it) {
if (it == data.end()) {
return "END";
} else {
return "'" + it->first + "->" + it->second + "'";
}
}
std::string ToString(const KVMap& data,
const KVMap::const_reverse_iterator& it) {
if (it == data.rend()) {
return "END";
} else {
return "'" + it->first + "->" + it->second + "'";
}
}
std::string ToString(const Iterator* it) {
if (!it->Valid()) {
return "END";
} else {
return "'" + it->key().ToString() + "->" + it->value().ToString() + "'";
}
}
std::string PickRandomKey(Random* rnd, const std::vector<std::string>& keys) {
if (keys.empty()) {
return "foo";
} else {
const int index = rnd->Uniform(keys.size());
std::string result = keys[index];
switch (rnd->Uniform(3)) {
case 0:
// Return an existing key
break;
case 1: {
// Attempt to return something smaller than an existing key
if (result.size() > 0 && result[result.size()-1] > '\0') {
result[result.size()-1]--;
}
break;
}
case 2: {
// Return something larger than an existing key
Increment(options_.comparator, &result);
break;
}
}
return result;
}
}
// Returns NULL if not running against a DB
DB* db() const { return constructor_->db(); }
private:
Options options_;
Constructor* constructor_;
};
// Test the empty key
TEST(Harness, SimpleEmptyKey) {
for (int i = 0; i < kNumTestArgs; i++) {
Init(kTestArgList[i]);
Random rnd(test::RandomSeed() + 1);
Add("", "v");
Test(&rnd);
}
}
TEST(Harness, SimpleSingle) {
for (int i = 0; i < kNumTestArgs; i++) {
Init(kTestArgList[i]);
Random rnd(test::RandomSeed() + 2);
Add("abc", "v");
Test(&rnd);
}
}
TEST(Harness, SimpleMulti) {
for (int i = 0; i < kNumTestArgs; i++) {
Init(kTestArgList[i]);
Random rnd(test::RandomSeed() + 3);
Add("abc", "v");
Add("abcd", "v");
Add("ac", "v2");
Test(&rnd);
}
}
TEST(Harness, SimpleSpecialKey) {
for (int i = 0; i < kNumTestArgs; i++) {
Init(kTestArgList[i]);
Random rnd(test::RandomSeed() + 4);
Add("\xff\xff", "v3");
Test(&rnd);
}
}
TEST(Harness, Randomized) {
for (int i = 0; i < kNumTestArgs; i++) {
Init(kTestArgList[i]);
Random rnd(test::RandomSeed() + 5);
for (int num_entries = 0; num_entries < 2000;
num_entries += (num_entries < 50 ? 1 : 200)) {
if ((num_entries % 10) == 0) {
fprintf(stderr, "case %d of %d: num_entries = %d\n",
(i + 1), int(kNumTestArgs), num_entries);
}
for (int e = 0; e < num_entries; e++) {
std::string v;
Add(test::RandomKey(&rnd, rnd.Skewed(4)),
test::RandomString(&rnd, rnd.Skewed(5), &v).ToString());
}
Test(&rnd);
}
}
}
TEST(Harness, RandomizedLongDB) {
Random rnd(test::RandomSeed());
TestArgs args = { DB_TEST, false, 16 };
Init(args);
int num_entries = 100000;
for (int e = 0; e < num_entries; e++) {
std::string v;
Add(test::RandomKey(&rnd, rnd.Skewed(4)),
test::RandomString(&rnd, rnd.Skewed(5), &v).ToString());
}
Test(&rnd);
// We must have created enough data to force merging
int files = 0;
for (int level = 0; level < config::kNumLevels; level++) {
std::string value;
char name[100];
snprintf(name, sizeof(name), "leveldb.num-files-at-level%d", level);
ASSERT_TRUE(db()->GetProperty(name, &value));
files += atoi(value.c_str());
}
ASSERT_GT(files, 0);
}
class MemTableTest { };
TEST(MemTableTest, Simple) {
InternalKeyComparator cmp(BytewiseComparator());
MemTable* memtable = new MemTable(cmp);
memtable->Ref();
WriteBatch batch;
WriteBatchInternal::SetSequence(&batch, 100);
batch.Put(std::string("k1"), std::string("v1"));
batch.Put(std::string("k2"), std::string("v2"));
batch.Put(std::string("k3"), std::string("v3"));
batch.Put(std::string("largekey"), std::string("vlarge"));
ASSERT_TRUE(WriteBatchInternal::InsertInto(&batch, memtable).ok());
Iterator* iter = memtable->NewIterator();
iter->SeekToFirst();
while (iter->Valid()) {
fprintf(stderr, "key: '%s' -> '%s'\n",
iter->key().ToString().c_str(),
iter->value().ToString().c_str());
iter->Next();
}
delete iter;
memtable->Unref();
}
static bool Between(uint64_t val, uint64_t low, uint64_t high) {
bool result = (val >= low) && (val <= high);
if (!result) {
fprintf(stderr, "Value %llu is not in range [%llu, %llu]\n",
(unsigned long long)(val),
(unsigned long long)(low),
(unsigned long long)(high));
}
return result;
}
class TableTest { };
TEST(TableTest, ApproximateOffsetOfPlain) {
TableConstructor c(BytewiseComparator());
c.Add("k01", "hello");
c.Add("k02", "hello2");
c.Add("k03", std::string(10000, 'x'));
c.Add("k04", std::string(200000, 'x'));
c.Add("k05", std::string(300000, 'x'));
c.Add("k06", "hello3");
c.Add("k07", std::string(100000, 'x'));
std::vector<std::string> keys;
KVMap kvmap;
Options options;
options.block_size = 1024;
options.compression = kNoCompression;
c.Finish(options, &keys, &kvmap);
ASSERT_TRUE(Between(c.ApproximateOffsetOf("abc"), 0, 0));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k01"), 0, 0));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k01a"), 0, 0));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k02"), 0, 0));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k03"), 0, 0));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k04"), 10000, 11000));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k04a"), 210000, 211000));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k05"), 210000, 211000));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k06"), 510000, 511000));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k07"), 510000, 511000));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("xyz"), 610000, 612000));
}
static bool SnappyCompressionSupported() {
std::string out;
Slice in = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
return port::Snappy_Compress(in.data(), in.size(), &out);
}
TEST(TableTest, ApproximateOffsetOfCompressed) {
if (!SnappyCompressionSupported()) {
fprintf(stderr, "skipping compression tests\n");
return;
}
Random rnd(301);
TableConstructor c(BytewiseComparator());
std::string tmp;
c.Add("k01", "hello");
c.Add("k02", test::CompressibleString(&rnd, 0.25, 10000, &tmp));
c.Add("k03", "hello3");
c.Add("k04", test::CompressibleString(&rnd, 0.25, 10000, &tmp));
std::vector<std::string> keys;
KVMap kvmap;
Options options;
options.block_size = 1024;
options.compression = kSnappyCompression;
c.Finish(options, &keys, &kvmap);
ASSERT_TRUE(Between(c.ApproximateOffsetOf("abc"), 0, 0));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k01"), 0, 0));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k02"), 0, 0));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k03"), 2000, 3000));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("k04"), 2000, 3000));
ASSERT_TRUE(Between(c.ApproximateOffsetOf("xyz"), 4000, 6000));
}
} // namespace leveldb
int main(int argc, char** argv) {
return leveldb::test::RunAllTests();
}

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src/leveldb/table/two_level_iterator.cc
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@ -1,182 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/two_level_iterator.h"
#include "leveldb/table.h"
#include "table/block.h"
#include "table/format.h"
#include "table/iterator_wrapper.h"
namespace leveldb {
namespace {
typedef Iterator* (*BlockFunction)(void*, const ReadOptions&, const Slice&);
class TwoLevelIterator: public Iterator {
public:
TwoLevelIterator(
Iterator* index_iter,
BlockFunction block_function,
void* arg,
const ReadOptions& options);
virtual ~TwoLevelIterator();
virtual void Seek(const Slice& target);
virtual void SeekToFirst();
virtual void SeekToLast();
virtual void Next();
virtual void Prev();
virtual bool Valid() const {
return data_iter_.Valid();
}
virtual Slice key() const {
assert(Valid());
return data_iter_.key();
}
virtual Slice value() const {
assert(Valid());
return data_iter_.value();
}
virtual Status status() const {
// It'd be nice if status() returned a const Status& instead of a Status
if (!index_iter_.status().ok()) {
return index_iter_.status();
} else if (data_iter_.iter() != NULL && !data_iter_.status().ok()) {
return data_iter_.status();
} else {
return status_;
}
}
private:
void SaveError(const Status& s) {
if (status_.ok() && !s.ok()) status_ = s;
}
void SkipEmptyDataBlocksForward();
void SkipEmptyDataBlocksBackward();
void SetDataIterator(Iterator* data_iter);
void InitDataBlock();
BlockFunction block_function_;
void* arg_;
const ReadOptions options_;
Status status_;
IteratorWrapper index_iter_;
IteratorWrapper data_iter_; // May be NULL
// If data_iter_ is non-NULL, then "data_block_handle_" holds the
// "index_value" passed to block_function_ to create the data_iter_.
std::string data_block_handle_;
};
TwoLevelIterator::TwoLevelIterator(
Iterator* index_iter,
BlockFunction block_function,
void* arg,
const ReadOptions& options)
: block_function_(block_function),
arg_(arg),
options_(options),
index_iter_(index_iter),
data_iter_(NULL) {
}
TwoLevelIterator::~TwoLevelIterator() {
}
void TwoLevelIterator::Seek(const Slice& target) {
index_iter_.Seek(target);
InitDataBlock();
if (data_iter_.iter() != NULL) data_iter_.Seek(target);
SkipEmptyDataBlocksForward();
}
void TwoLevelIterator::SeekToFirst() {
index_iter_.SeekToFirst();
InitDataBlock();
if (data_iter_.iter() != NULL) data_iter_.SeekToFirst();
SkipEmptyDataBlocksForward();
}
void TwoLevelIterator::SeekToLast() {
index_iter_.SeekToLast();
InitDataBlock();
if (data_iter_.iter() != NULL) data_iter_.SeekToLast();
SkipEmptyDataBlocksBackward();
}
void TwoLevelIterator::Next() {
assert(Valid());
data_iter_.Next();
SkipEmptyDataBlocksForward();
}
void TwoLevelIterator::Prev() {
assert(Valid());
data_iter_.Prev();
SkipEmptyDataBlocksBackward();
}
void TwoLevelIterator::SkipEmptyDataBlocksForward() {
while (data_iter_.iter() == NULL || !data_iter_.Valid()) {
// Move to next block
if (!index_iter_.Valid()) {
SetDataIterator(NULL);
return;
}
index_iter_.Next();
InitDataBlock();
if (data_iter_.iter() != NULL) data_iter_.SeekToFirst();
}
}
void TwoLevelIterator::SkipEmptyDataBlocksBackward() {
while (data_iter_.iter() == NULL || !data_iter_.Valid()) {
// Move to next block
if (!index_iter_.Valid()) {
SetDataIterator(NULL);
return;
}
index_iter_.Prev();
InitDataBlock();
if (data_iter_.iter() != NULL) data_iter_.SeekToLast();
}
}
void TwoLevelIterator::SetDataIterator(Iterator* data_iter) {
if (data_iter_.iter() != NULL) SaveError(data_iter_.status());
data_iter_.Set(data_iter);
}
void TwoLevelIterator::InitDataBlock() {
if (!index_iter_.Valid()) {
SetDataIterator(NULL);
} else {
Slice handle = index_iter_.value();
if (data_iter_.iter() != NULL && handle.compare(data_block_handle_) == 0) {
// data_iter_ is already constructed with this iterator, so
// no need to change anything
} else {
Iterator* iter = (*block_function_)(arg_, options_, handle);
data_block_handle_.assign(handle.data(), handle.size());
SetDataIterator(iter);
}
}
}
} // namespace
Iterator* NewTwoLevelIterator(
Iterator* index_iter,
BlockFunction block_function,
void* arg,
const ReadOptions& options) {
return new TwoLevelIterator(index_iter, block_function, arg, options);
}
} // namespace leveldb

34
src/leveldb/table/two_level_iterator.h
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@ -1,34 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_TABLE_TWO_LEVEL_ITERATOR_H_
#define STORAGE_LEVELDB_TABLE_TWO_LEVEL_ITERATOR_H_
#include "leveldb/iterator.h"
namespace leveldb {
struct ReadOptions;
// Return a new two level iterator. A two-level iterator contains an
// index iterator whose values point to a sequence of blocks where
// each block is itself a sequence of key,value pairs. The returned
// two-level iterator yields the concatenation of all key/value pairs
// in the sequence of blocks. Takes ownership of "index_iter" and
// will delete it when no longer needed.
//
// Uses a supplied function to convert an index_iter value into
// an iterator over the contents of the corresponding block.
extern Iterator* NewTwoLevelIterator(
Iterator* index_iter,
Iterator* (*block_function)(
void* arg,
const ReadOptions& options,
const Slice& index_value),
void* arg,
const ReadOptions& options);
} // namespace leveldb
#endif // STORAGE_LEVELDB_TABLE_TWO_LEVEL_ITERATOR_H_

68
src/leveldb/util/arena.cc
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@ -1,68 +0,0 @@
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "util/arena.h"
#include <assert.h>
namespace leveldb {
static const int kBlockSize = 4096;
Arena::Arena() {
blocks_memory_ = 0;
alloc_ptr_ = NULL; // First allocation will allocate a block
alloc_bytes_remaining_ = 0;
}
Arena::~Arena() {
for (size_t i = 0; i < blocks_.size(); i++) {
delete[] blocks_[i];
}
}
char* Arena::AllocateFallback(size_t bytes) {
if (bytes > kBlockSize / 4) {
// Object is more than a quarter of our block size. Allocate it separately
// to avoid wasting too much space in leftover bytes.
char* result = AllocateNewBlock(bytes);
return result;
}
// We waste the remaining space in the current block.
alloc_ptr_ = AllocateNewBlock(kBlockSize);
alloc_bytes_remaining_ = kBlockSize;
char* result = alloc_ptr_;
alloc_ptr_ += bytes;
alloc_bytes_remaining_ -= bytes;
return result;
}
char* Arena::AllocateAligned(size_t bytes) {
const int align = sizeof(void*); // We'll align to pointer size
assert((align & (align-1)) == 0); // Pointer size should be a power of 2
size_t current_mod = reinterpret_cast<uintptr_t>(alloc_ptr_) & (align-1);
size_t slop = (current_mod == 0 ? 0 : align - current_mod);
size_t needed = bytes + slop;
char* result;
if (needed <= alloc_bytes_remaining_) {
result = alloc_ptr_ + slop;
alloc_ptr_ += needed;
alloc_bytes_remaining_ -= needed;
} else {
// AllocateFallback always returned aligned memory
result = AllocateFallback(bytes);
}
assert((reinterpret_cast<uintptr_t>(result) & (align-1)) == 0);
return result;
}
char* Arena::AllocateNewBlock(size_t block_bytes) {
char* result = new char[block_bytes];
blocks_memory_ += block_bytes;
blocks_.push_back(result);
return result;
}
} // namespace leveldb

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