BRNSystems/minetest
1
0
Fork 0
forked from Mirrorlandia_minetest/minetest
Code Pull Requests 1 Activity

Handle SQLITE_BUSY errors gracefully

Browse Source 
This allows other applications (e.g. minetestmapper) to interrogate
the database while minetest is running, without causing an almost
certain minetest crash.
This commit is contained in:
Rogier 2015-12-23 11:38:50 +01:00 committed by est31
parent 848b050a56
commit c6bb6f99d1
2 changed files with 64 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
src/database-sqlite3.cpp
View File

@ -31,10 +31,19 @@ SQLite format specification:
#include "filesys.h"
#include "exceptions.h"
#include "settings.h"
#include "porting.h"
#include "util/string.h"
#include <cassert>
// When to print messages when the database is being held locked by another process
// Note: I've seen occasional delays of over 250ms while running minetestmapper.
#define BUSY_INFO_TRESHOLD 100 // Print first informational message after 100ms.
#define BUSY_WARNING_TRESHOLD 250 // Print warning message after 250ms. Lag is increased.
#define BUSY_ERROR_TRESHOLD 1000 // Print error message after 1000ms. Significant lag.
#define BUSY_FATAL_TRESHOLD 3000 // Allow SQLITE_BUSY to be returned, which will cause a minetest crash.
#define BUSY_ERROR_INTERVAL 10000 // Safety net: report again every 10 seconds
#define SQLRES(s, r) \
if ((s) != (r)) { \
@ -56,6 +65,51 @@ SQLite format specification:
sqlite3_errmsg(m_database)); \
}
int Database_SQLite3::busyHandler(void *data, int count)
{
s64 &first_time = reinterpret_cast<s64 *>(data)[0];
s64 &prev_time = reinterpret_cast<s64 *>(data)[1];
s64 cur_time = getTimeMs();
if (count == 0) {
first_time = cur_time;
prev_time = first_time;
} else {
while (cur_time < prev_time)
cur_time += s64(1)<<32;
}
if (cur_time - first_time < BUSY_INFO_TRESHOLD) {
; // do nothing
} else if (cur_time - first_time >= BUSY_INFO_TRESHOLD &&
prev_time - first_time < BUSY_INFO_TRESHOLD) {
infostream << "SQLite3 database has been locked for "
<< cur_time - first_time << " ms." << std::endl;
} else if (cur_time - first_time >= BUSY_WARNING_TRESHOLD &&
prev_time - first_time < BUSY_WARNING_TRESHOLD) {
warningstream << "Sqlite3 database has been locked for "
<< cur_time - first_time << " ms." << std::endl;
} else if (cur_time - first_time >= BUSY_ERROR_TRESHOLD &&
prev_time - first_time < BUSY_ERROR_TRESHOLD) {
errorstream << "SQLite3 database has been locked for "
<< cur_time - first_time << " ms; this causes lag." << std::endl;
} else if (cur_time - first_time >= BUSY_FATAL_TRESHOLD &&
prev_time - first_time < BUSY_FATAL_TRESHOLD) {
errorstream << "Sqlite3 database has been locked for "
<< cur_time - first_time << " ms - giving up!" << std::endl;
} else if ((cur_time - first_time) / BUSY_ERROR_INTERVAL !=
(prev_time - first_time) / BUSY_ERROR_INTERVAL) {
// Safety net: keep reporting every BUSY_ERROR_INTERVAL
errorstream << "SQLite3 database has been locked for "
<< (cur_time - first_time) / 1000 << " seconds!" << std::endl;
}
prev_time = cur_time;
// Make sqlite transaction fail if delay exceeds BUSY_FATAL_TRESHOLD
return cur_time - first_time < BUSY_FATAL_TRESHOLD;
}
Database_SQLite3::Database_SQLite3(const std::string &savedir) :
m_initialized(false),
@ -107,6 +161,12 @@ void Database_SQLite3::openDatabase()
throw FileNotGoodException("Cannot open database file");
}
if (sqlite3_busy_handler(m_database, sqlite3BusyHandler, busy_handler_data) != SQLITE_OK) {
errorstream << "SQLite3 database failed to set busy handler: "
<< sqlite3_errmsg(m_database) << std::endl;
throw FileNotGoodException("Failed to set busy handler for sqlite connection");
}
if (needs_create) {
createDatabase();
}

4
src/database-sqlite3.h
View File

@ -63,6 +63,10 @@ private:
sqlite3_stmt *m_stmt_delete;
sqlite3_stmt *m_stmt_begin;
sqlite3_stmt *m_stmt_end;
s64 m_busy_handler_data[2];
static int busyHandler(void *data, int count);
};
#endif