wiki.techinc.nl/includes/db/DatabaseMysql.php
Aaron Schulz 3675f1d447 Make Database disconnect and error suppression more robust
* Disallow $ignoreErrors in query() on deadlocks, since that would otherwise
  silently rollback all changes from any other callers.
* Move recoverability checks for disconnects to canRecoverFromDisconnect().
* The first write of a DBO_TRX transaction is now considered recoverable.
* Run onTransactionResolution() callbacks on disconnect/deadlock rollback.
  Some DeferrableUpdate need this to know to abort.
* Disallow $ignoreErrors on disconnects considered unrecoverable. This
  makes it so that query() callers cannot cause writes from other callers
  to be silently lost, which is hard to reason about.
* Moved ping() logic to simple reconnect() method and ping() simply do
  a dummy SELECT, which triggeres reconnection if safe. Previously,
  ping() might cause subtle partial transaction loss.
* Remove ping() from strencode(), which would cause partial transaction
  loss where it actually reached.
* Remove mysqlPing() per https://bugs.php.net/bug.php?id=52561.

Bug: T142079
Change-Id: Ifb7f772ae849d67c0d92240a115c3f392e252937
2016-08-11 07:26:33 +00:00

204 lines
4.7 KiB
PHP

<?php
/**
* This is the MySQL database abstraction layer.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup Database
*/
/**
* Database abstraction object for PHP extension mysql.
*
* @ingroup Database
* @see Database
*/
class DatabaseMysql extends DatabaseMysqlBase {
/**
* @param string $sql
* @return resource False on error
*/
protected function doQuery( $sql ) {
$conn = $this->getBindingHandle();
if ( $this->bufferResults() ) {
$ret = mysql_query( $sql, $conn );
} else {
$ret = mysql_unbuffered_query( $sql, $conn );
}
return $ret;
}
/**
* @param string $realServer
* @return bool|resource MySQL Database connection or false on failure to connect
* @throws DBConnectionError
*/
protected function mysqlConnect( $realServer ) {
# Avoid a suppressed fatal error, which is very hard to track down
if ( !extension_loaded( 'mysql' ) ) {
throw new DBConnectionError(
$this,
"MySQL functions missing, have you compiled PHP with the --with-mysql option?\n"
);
}
$connFlags = 0;
if ( $this->mFlags & DBO_SSL ) {
$connFlags |= MYSQL_CLIENT_SSL;
}
if ( $this->mFlags & DBO_COMPRESS ) {
$connFlags |= MYSQL_CLIENT_COMPRESS;
}
if ( ini_get( 'mysql.connect_timeout' ) <= 3 ) {
$numAttempts = 2;
} else {
$numAttempts = 1;
}
$conn = false;
# The kernel's default SYN retransmission period is far too slow for us,
# so we use a short timeout plus a manual retry. Retrying means that a small
# but finite rate of SYN packet loss won't cause user-visible errors.
for ( $i = 0; $i < $numAttempts && !$conn; $i++ ) {
if ( $i > 1 ) {
usleep( 1000 );
}
if ( $this->mFlags & DBO_PERSISTENT ) {
$conn = mysql_pconnect( $realServer, $this->mUser, $this->mPassword, $connFlags );
} else {
# Create a new connection...
$conn = mysql_connect( $realServer, $this->mUser, $this->mPassword, true, $connFlags );
}
}
return $conn;
}
/**
* @param string $charset
* @return bool
*/
protected function mysqlSetCharset( $charset ) {
$conn = $this->getBindingHandle();
if ( function_exists( 'mysql_set_charset' ) ) {
return mysql_set_charset( $charset, $conn );
} else {
return $this->query( 'SET NAMES ' . $charset, __METHOD__ );
}
}
/**
* @return bool
*/
protected function closeConnection() {
$conn = $this->getBindingHandle();
return mysql_close( $conn );
}
/**
* @return int
*/
function insertId() {
$conn = $this->getBindingHandle();
return mysql_insert_id( $conn );
}
/**
* @return int
*/
function lastErrno() {
if ( $this->mConn ) {
return mysql_errno( $this->mConn );
} else {
return mysql_errno();
}
}
/**
* @return int
*/
function affectedRows() {
$conn = $this->getBindingHandle();
return mysql_affected_rows( $conn );
}
/**
* @param string $db
* @return bool
*/
function selectDB( $db ) {
$conn = $this->getBindingHandle();
$this->mDBname = $db;
return mysql_select_db( $db, $conn );
}
protected function mysqlFreeResult( $res ) {
return mysql_free_result( $res );
}
protected function mysqlFetchObject( $res ) {
return mysql_fetch_object( $res );
}
protected function mysqlFetchArray( $res ) {
return mysql_fetch_array( $res );
}
protected function mysqlNumRows( $res ) {
return mysql_num_rows( $res );
}
protected function mysqlNumFields( $res ) {
return mysql_num_fields( $res );
}
protected function mysqlFetchField( $res, $n ) {
return mysql_fetch_field( $res, $n );
}
protected function mysqlFieldName( $res, $n ) {
return mysql_field_name( $res, $n );
}
protected function mysqlFieldType( $res, $n ) {
return mysql_field_type( $res, $n );
}
protected function mysqlDataSeek( $res, $row ) {
return mysql_data_seek( $res, $row );
}
protected function mysqlError( $conn = null ) {
return ( $conn !== null ) ? mysql_error( $conn ) : mysql_error(); // avoid warning
}
protected function mysqlRealEscapeString( $s ) {
$conn = $this->getBindingHandle();
return mysql_real_escape_string( $s, $conn );
}
}