--- /dev/null
+<?php
+/**
+ * Generator of database load balancing objects.
+ *
+ * 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
+ */
+
+/**
+ * Class for ensuring a consistent ordering of events as seen by the user, despite replication.
+ * Kind of like Hawking's [[Chronology Protection Agency]].
+ */
+class ChronologyProtector {
+ var $startupPos;
+ var $shutdownPos = array();
+
+ /**
+ * Initialise a LoadBalancer to give it appropriate chronology protection.
+ *
+ * @param $lb LoadBalancer
+ */
+ function initLB( $lb ) {
+ if ( $this->startupPos === null ) {
+ if ( !empty( $_SESSION[__CLASS__] ) ) {
+ $this->startupPos = $_SESSION[__CLASS__];
+ }
+ }
+ if ( !$this->startupPos ) {
+ return;
+ }
+ $masterName = $lb->getServerName( 0 );
+
+ if ( $lb->getServerCount() > 1 && !empty( $this->startupPos[$masterName] ) ) {
+ $info = $lb->parentInfo();
+ $pos = $this->startupPos[$masterName];
+ wfDebug( __METHOD__ . ": LB " . $info['id'] . " waiting for master pos $pos\n" );
+ $lb->waitFor( $this->startupPos[$masterName] );
+ }
+ }
+
+ /**
+ * Notify the ChronologyProtector that the LoadBalancer is about to shut
+ * down. Saves replication positions.
+ *
+ * @param $lb LoadBalancer
+ */
+ function shutdownLB( $lb ) {
+ // Don't start a session, don't bother with non-replicated setups
+ if ( strval( session_id() ) == '' || $lb->getServerCount() <= 1 ) {
+ return;
+ }
+ $masterName = $lb->getServerName( 0 );
+ if ( isset( $this->shutdownPos[$masterName] ) ) {
+ // Already done
+ return;
+ }
+ // Only save the position if writes have been done on the connection
+ $db = $lb->getAnyOpenConnection( 0 );
+ $info = $lb->parentInfo();
+ if ( !$db || !$db->doneWrites() ) {
+ wfDebug( __METHOD__ . ": LB {$info['id']}, no writes done\n" );
+ return;
+ }
+ $pos = $db->getMasterPos();
+ wfDebug( __METHOD__ . ": LB {$info['id']} has master pos $pos\n" );
+ $this->shutdownPos[$masterName] = $pos;
+ }
+
+ /**
+ * Notify the ChronologyProtector that the LBFactory is done calling shutdownLB() for now.
+ * May commit chronology data to persistent storage.
+ */
+ function shutdown() {
+ if ( session_id() != '' && count( $this->shutdownPos ) ) {
+ wfDebug( __METHOD__ . ": saving master pos for " .
+ count( $this->shutdownPos ) . " master(s)\n" );
+ $_SESSION[__CLASS__] = $this->shutdownPos;
+ }
+ }
+}
parent::__construct( "Mediawiki tried to access the database via wfGetDB(). This is not allowed." );
}
}
-
-/**
- * Class for ensuring a consistent ordering of events as seen by the user, despite replication.
- * Kind of like Hawking's [[Chronology Protection Agency]].
- */
-class ChronologyProtector {
- var $startupPos;
- var $shutdownPos = array();
-
- /**
- * Initialise a LoadBalancer to give it appropriate chronology protection.
- *
- * @param $lb LoadBalancer
- */
- function initLB( $lb ) {
- if ( $this->startupPos === null ) {
- if ( !empty( $_SESSION[__CLASS__] ) ) {
- $this->startupPos = $_SESSION[__CLASS__];
- }
- }
- if ( !$this->startupPos ) {
- return;
- }
- $masterName = $lb->getServerName( 0 );
-
- if ( $lb->getServerCount() > 1 && !empty( $this->startupPos[$masterName] ) ) {
- $info = $lb->parentInfo();
- $pos = $this->startupPos[$masterName];
- wfDebug( __METHOD__ . ": LB " . $info['id'] . " waiting for master pos $pos\n" );
- $lb->waitFor( $this->startupPos[$masterName] );
- }
- }
-
- /**
- * Notify the ChronologyProtector that the LoadBalancer is about to shut
- * down. Saves replication positions.
- *
- * @param $lb LoadBalancer
- */
- function shutdownLB( $lb ) {
- // Don't start a session, don't bother with non-replicated setups
- if ( strval( session_id() ) == '' || $lb->getServerCount() <= 1 ) {
- return;
- }
- $masterName = $lb->getServerName( 0 );
- if ( isset( $this->shutdownPos[$masterName] ) ) {
- // Already done
- return;
- }
- // Only save the position if writes have been done on the connection
- $db = $lb->getAnyOpenConnection( 0 );
- $info = $lb->parentInfo();
- if ( !$db || !$db->doneWrites() ) {
- wfDebug( __METHOD__ . ": LB {$info['id']}, no writes done\n" );
- return;
- }
- $pos = $db->getMasterPos();
- wfDebug( __METHOD__ . ": LB {$info['id']} has master pos $pos\n" );
- $this->shutdownPos[$masterName] = $pos;
- }
-
- /**
- * Notify the ChronologyProtector that the LBFactory is done calling shutdownLB() for now.
- * May commit chronology data to persistent storage.
- */
- function shutdown() {
- if ( session_id() != '' && count( $this->shutdownPos ) ) {
- wfDebug( __METHOD__ . ": saving master pos for " .
- count( $this->shutdownPos ) . " master(s)\n" );
- $_SESSION[__CLASS__] = $this->shutdownPos;
- }
- }
-}