'CsvStatsOutput' => __DIR__ . '/maintenance/language/StatOutputs.php',
'CurlHttpRequest' => __DIR__ . '/includes/HttpFunctions.php',
'DBAccessBase' => __DIR__ . '/includes/dao/DBAccessBase.php',
- 'DBAccessError' => __DIR__ . '/includes/db/LBFactory.php',
+ 'DBAccessError' => __DIR__ . '/includes/db/loadbalancer/LBFactory.php',
'DBAccessObjectUtils' => __DIR__ . '/includes/dao/DBAccessObjectUtils.php',
'DBConnRef' => __DIR__ . '/includes/db/DBConnRef.php',
'DBConnectionError' => __DIR__ . '/includes/db/DatabaseError.php',
'JsonContentHandler' => __DIR__ . '/includes/content/JsonContentHandler.php',
'KkConverter' => __DIR__ . '/languages/classes/LanguageKk.php',
'KuConverter' => __DIR__ . '/languages/classes/LanguageKu.php',
- 'LBFactory' => __DIR__ . '/includes/db/LBFactory.php',
- 'LBFactoryFake' => __DIR__ . '/includes/db/LBFactory.php',
- 'LBFactoryMulti' => __DIR__ . '/includes/db/LBFactoryMulti.php',
- 'LBFactorySimple' => __DIR__ . '/includes/db/LBFactory.php',
- 'LBFactorySingle' => __DIR__ . '/includes/db/LBFactorySingle.php',
+ 'LBFactory' => __DIR__ . '/includes/db/loadbalancer/LBFactory.php',
+ 'LBFactoryFake' => __DIR__ . '/includes/db/loadbalancer/LBFactoryFake.php',
+ 'LBFactoryMulti' => __DIR__ . '/includes/db/loadbalancer/LBFactoryMulti.php',
+ 'LBFactorySimple' => __DIR__ . '/includes/db/loadbalancer/LBFactorySimple.php',
+ 'LBFactorySingle' => __DIR__ . '/includes/db/loadbalancer/LBFactorySingle.php',
'LCStore' => __DIR__ . '/includes/cache/LocalisationCache.php',
'LCStoreCDB' => __DIR__ . '/includes/cache/LocalisationCache.php',
'LCStoreDB' => __DIR__ . '/includes/cache/LocalisationCache.php',
'ListDuplicatedFilesPage' => __DIR__ . '/includes/specials/SpecialListDuplicatedFiles.php',
'ListVariants' => __DIR__ . '/maintenance/language/listVariants.php',
'ListredirectsPage' => __DIR__ . '/includes/specials/SpecialListredirects.php',
- 'LoadBalancer' => __DIR__ . '/includes/db/LoadBalancer.php',
- 'LoadBalancerSingle' => __DIR__ . '/includes/db/LBFactorySingle.php',
- 'LoadMonitor' => __DIR__ . '/includes/db/LoadMonitor.php',
- 'LoadMonitorMySQL' => __DIR__ . '/includes/db/LoadMonitorMySQL.php',
- 'LoadMonitorNull' => __DIR__ . '/includes/db/LoadMonitor.php',
+ 'LoadBalancer' => __DIR__ . '/includes/db/loadbalancer/LoadBalancer.php',
+ 'LoadBalancerSingle' => __DIR__ . '/includes/db/loadbalancer/LBFactorySingle.php',
+ 'LoadMonitor' => __DIR__ . '/includes/db/loadbalancer/LoadMonitor.php',
+ 'LoadMonitorMySQL' => __DIR__ . '/includes/db/loadbalancer/LoadMonitorMySQL.php',
+ 'LoadMonitorNull' => __DIR__ . '/includes/db/loadbalancer/LoadMonitor.php',
'LocalFile' => __DIR__ . '/includes/filerepo/file/LocalFile.php',
'LocalFileDeleteBatch' => __DIR__ . '/includes/filerepo/file/LocalFile.php',
'LocalFileMoveBatch' => __DIR__ . '/includes/filerepo/file/LocalFile.php',
+++ /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
- */
-
-/**
- * An interface for generating database load balancers
- * @ingroup Database
- */
-abstract class LBFactory {
- /** @var LBFactory */
- private static $instance;
-
- /**
- * Disables all access to the load balancer, will cause all database access
- * to throw a DBAccessError
- */
- public static function disableBackend() {
- global $wgLBFactoryConf;
- self::$instance = new LBFactoryFake( $wgLBFactoryConf );
- }
-
- /**
- * Get an LBFactory instance
- *
- * @return LBFactory
- */
- public static function singleton() {
- global $wgLBFactoryConf;
-
- if ( is_null( self::$instance ) ) {
- $class = self::getLBFactoryClass( $wgLBFactoryConf );
-
- self::$instance = new $class( $wgLBFactoryConf );
- }
-
- return self::$instance;
- }
-
- /**
- * Returns the LBFactory class to use and the load balancer configuration.
- *
- * @param array $config (e.g. $wgLBFactoryConf)
- * @return string Class name
- */
- public static function getLBFactoryClass( array $config ) {
- // For configuration backward compatibility after removing
- // underscores from class names in MediaWiki 1.23.
- $bcClasses = array(
- 'LBFactory_Simple' => 'LBFactorySimple',
- 'LBFactory_Single' => 'LBFactorySingle',
- 'LBFactory_Multi' => 'LBFactoryMulti',
- 'LBFactory_Fake' => 'LBFactoryFake',
- );
-
- $class = $config['class'];
-
- if ( isset( $bcClasses[$class] ) ) {
- $class = $bcClasses[$class];
- wfDeprecated(
- '$wgLBFactoryConf must be updated. See RELEASE-NOTES for details',
- '1.23'
- );
- }
-
- return $class;
- }
-
- /**
- * Shut down, close connections and destroy the cached instance.
- */
- public static function destroyInstance() {
- if ( self::$instance ) {
- self::$instance->shutdown();
- self::$instance->forEachLBCallMethod( 'closeAll' );
- self::$instance = null;
- }
- }
-
- /**
- * Set the instance to be the given object
- *
- * @param LBFactory $instance
- */
- public static function setInstance( $instance ) {
- self::destroyInstance();
- self::$instance = $instance;
- }
-
- /**
- * Construct a factory based on a configuration array (typically from $wgLBFactoryConf)
- * @param array $conf
- */
- abstract public function __construct( array $conf );
-
- /**
- * Create a new load balancer object. The resulting object will be untracked,
- * not chronology-protected, and the caller is responsible for cleaning it up.
- *
- * @param bool|string $wiki Wiki ID, or false for the current wiki
- * @return LoadBalancer
- */
- abstract public function newMainLB( $wiki = false );
-
- /**
- * Get a cached (tracked) load balancer object.
- *
- * @param bool|string $wiki Wiki ID, or false for the current wiki
- * @return LoadBalancer
- */
- abstract public function getMainLB( $wiki = false );
-
- /**
- * Create a new load balancer for external storage. The resulting object will be
- * untracked, not chronology-protected, and the caller is responsible for
- * cleaning it up.
- *
- * @param string $cluster External storage cluster, or false for core
- * @param bool|string $wiki Wiki ID, or false for the current wiki
- * @return LoadBalancer
- */
- abstract protected function newExternalLB( $cluster, $wiki = false );
-
- /**
- * Get a cached (tracked) load balancer for external storage
- *
- * @param string $cluster External storage cluster, or false for core
- * @param bool|string $wiki Wiki ID, or false for the current wiki
- * @return LoadBalancer
- */
- abstract public function &getExternalLB( $cluster, $wiki = false );
-
- /**
- * Execute a function for each tracked load balancer
- * The callback is called with the load balancer as the first parameter,
- * and $params passed as the subsequent parameters.
- *
- * @param callable $callback
- * @param array $params
- */
- abstract public function forEachLB( $callback, array $params = array() );
-
- /**
- * Prepare all tracked load balancers for shutdown
- * STUB
- */
- public function shutdown() {
- }
-
- /**
- * Call a method of each tracked load balancer
- *
- * @param string $methodName
- * @param array $args
- */
- private function forEachLBCallMethod( $methodName, array $args = array() ) {
- $this->forEachLB( function ( LoadBalancer $loadBalancer, $methodName, array $args ) {
- call_user_func_array( array( $loadBalancer, $methodName ), $args );
- }, array( $methodName, $args ) );
- }
-
- /**
- * Commit on all connections. Done for two reasons:
- * 1. To commit changes to the masters.
- * 2. To release the snapshot on all connections, master and slave.
- */
- public function commitAll() {
- $this->forEachLBCallMethod( 'commitAll' );
- }
-
- /**
- * Commit changes on all master connections
- */
- public function commitMasterChanges() {
- $this->forEachLBCallMethod( 'commitMasterChanges' );
- }
-
- /**
- * Rollback changes on all master connections
- * @since 1.23
- */
- public function rollbackMasterChanges() {
- $this->forEachLBCallMethod( 'rollbackMasterChanges' );
- }
-
- /**
- * Detemine if any master connection has pending changes.
- * @since 1.23
- * @return bool
- */
- public function hasMasterChanges() {
- $ret = false;
- $this->forEachLB( function ( LoadBalancer $lb ) use ( &$ret ) {
- $ret = $ret || $lb->hasMasterChanges();
- } );
- return $ret;
- }
-}
-
-/**
- * A simple single-master LBFactory that gets its configuration from the b/c globals
- */
-class LBFactorySimple extends LBFactory {
- /** @var LoadBalancer */
- private $mainLB;
-
- /** @var LoadBalancer[] */
- private $extLBs = array();
-
- /** @var ChronologyProtector */
- private $chronProt;
-
- public function __construct( array $conf ) {
- $this->chronProt = new ChronologyProtector;
- }
-
- /**
- * @param bool|string $wiki
- * @return LoadBalancer
- */
- public function newMainLB( $wiki = false ) {
- global $wgDBservers;
- if ( $wgDBservers ) {
- $servers = $wgDBservers;
- } else {
- global $wgDBserver, $wgDBuser, $wgDBpassword, $wgDBname, $wgDBtype, $wgDebugDumpSql;
- global $wgDBssl, $wgDBcompress;
-
- $flags = DBO_DEFAULT;
- if ( $wgDebugDumpSql ) {
- $flags |= DBO_DEBUG;
- }
- if ( $wgDBssl ) {
- $flags |= DBO_SSL;
- }
- if ( $wgDBcompress ) {
- $flags |= DBO_COMPRESS;
- }
-
- $servers = array( array(
- 'host' => $wgDBserver,
- 'user' => $wgDBuser,
- 'password' => $wgDBpassword,
- 'dbname' => $wgDBname,
- 'type' => $wgDBtype,
- 'load' => 1,
- 'flags' => $flags
- ) );
- }
-
- return new LoadBalancer( array(
- 'servers' => $servers,
- ) );
- }
-
- /**
- * @param bool|string $wiki
- * @return LoadBalancer
- */
- public function getMainLB( $wiki = false ) {
- if ( !isset( $this->mainLB ) ) {
- $this->mainLB = $this->newMainLB( $wiki );
- $this->mainLB->parentInfo( array( 'id' => 'main' ) );
- $this->chronProt->initLB( $this->mainLB );
- }
-
- return $this->mainLB;
- }
-
- /**
- * @throws MWException
- * @param string $cluster
- * @param bool|string $wiki
- * @return LoadBalancer
- */
- protected function newExternalLB( $cluster, $wiki = false ) {
- global $wgExternalServers;
- if ( !isset( $wgExternalServers[$cluster] ) ) {
- throw new MWException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
- }
-
- return new LoadBalancer( array(
- 'servers' => $wgExternalServers[$cluster]
- ) );
- }
-
- /**
- * @param string $cluster
- * @param bool|string $wiki
- * @return array
- */
- public function &getExternalLB( $cluster, $wiki = false ) {
- if ( !isset( $this->extLBs[$cluster] ) ) {
- $this->extLBs[$cluster] = $this->newExternalLB( $cluster, $wiki );
- $this->extLBs[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
- $this->chronProt->initLB( $this->extLBs[$cluster] );
- }
-
- return $this->extLBs[$cluster];
- }
-
- /**
- * Execute a function for each tracked load balancer
- * The callback is called with the load balancer as the first parameter,
- * and $params passed as the subsequent parameters.
- *
- * @param callable $callback
- * @param array $params
- */
- public function forEachLB( $callback, array $params = array() ) {
- if ( isset( $this->mainLB ) ) {
- call_user_func_array( $callback, array_merge( array( $this->mainLB ), $params ) );
- }
- foreach ( $this->extLBs as $lb ) {
- call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
- }
- }
-
- public function shutdown() {
- if ( $this->mainLB ) {
- $this->chronProt->shutdownLB( $this->mainLB );
- }
- foreach ( $this->extLBs as $extLB ) {
- $this->chronProt->shutdownLB( $extLB );
- }
- $this->chronProt->shutdown();
- $this->commitMasterChanges();
- }
-}
-
-/**
- * LBFactory class that throws an error on any attempt to use it.
- * This will typically be done via wfGetDB().
- * Call LBFactory::disableBackend() to start using this, and
- * LBFactory::enableBackend() to return to normal behavior
- */
-class LBFactoryFake extends LBFactory {
- public function __construct( array $conf ) {
- }
-
- public function newMainLB( $wiki = false ) {
- throw new DBAccessError;
- }
-
- public function getMainLB( $wiki = false ) {
- throw new DBAccessError;
- }
-
- protected function newExternalLB( $cluster, $wiki = false ) {
- throw new DBAccessError;
- }
-
- public function &getExternalLB( $cluster, $wiki = false ) {
- throw new DBAccessError;
- }
-
- public function forEachLB( $callback, array $params = array() ) {
- }
-}
-
-/**
- * Exception class for attempted DB access
- */
-class DBAccessError extends MWException {
- public function __construct() {
- parent::__construct( "Mediawiki tried to access the database via wfGetDB(). " .
- "This is not allowed." );
- }
-}
+++ /dev/null
-<?php
-/**
- * Advanced generator of database load balancing objects for wiki farms.
- *
- * 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
- */
-
-/**
- * A multi-wiki, multi-master factory for Wikimedia and similar installations.
- * Ignores the old configuration globals
- *
- * Configuration:
- * sectionsByDB A map of database names to section names.
- *
- * sectionLoads A 2-d map. For each section, gives a map of server names to
- * load ratios. For example:
- * array(
- * 'section1' => array(
- * 'db1' => 100,
- * 'db2' => 100
- * )
- * )
- *
- * serverTemplate A server info associative array as documented for $wgDBservers.
- * The host, hostName and load entries will be overridden.
- *
- * groupLoadsBySection A 3-d map giving server load ratios for each section and group.
- * For example:
- * array(
- * 'section1' => array(
- * 'group1' => array(
- * 'db1' => 100,
- * 'db2' => 100
- * )
- * )
- * )
- *
- * groupLoadsByDB A 3-d map giving server load ratios by DB name.
- *
- * hostsByName A map of hostname to IP address.
- *
- * externalLoads A map of external storage cluster name to server load map.
- *
- * externalTemplateOverrides A set of server info keys overriding serverTemplate for external
- * storage.
- *
- * templateOverridesByServer A 2-d map overriding serverTemplate and
- * externalTemplateOverrides on a server-by-server basis. Applies
- * to both core and external storage.
- *
- * templateOverridesByCluster A 2-d map overriding the server info by external storage cluster.
- *
- * masterTemplateOverrides An override array for all master servers.
- *
- * readOnlyBySection A map of section name to read-only message.
- * Missing or false for read/write.
- *
- * @ingroup Database
- */
-class LBFactoryMulti extends LBFactory {
- // Required settings
-
- /** @var array A map of database names to section names */
- private $sectionsByDB;
-
- /**
- * @var array A 2-d map. For each section, gives a map of server names to
- * load ratios
- */
- private $sectionLoads;
-
- /**
- * @var array A server info associative array as documented for
- * $wgDBservers. The host, hostName and load entries will be
- * overridden
- */
- private $serverTemplate;
-
- // Optional settings
-
- /** @var array A 3-d map giving server load ratios for each section and group */
- private $groupLoadsBySection = array();
-
- /** @var array A 3-d map giving server load ratios by DB name */
- private $groupLoadsByDB = array();
-
- /** @var array A map of hostname to IP address */
- private $hostsByName = array();
-
- /** @var array A map of external storage cluster name to server load map */
- private $externalLoads = array();
-
- /**
- * @var array A set of server info keys overriding serverTemplate for
- * external storage
- */
- private $externalTemplateOverrides;
-
- /**
- * @var array A 2-d map overriding serverTemplate and
- * externalTemplateOverrides on a server-by-server basis. Applies to both
- * core and external storage
- */
- private $templateOverridesByServer;
-
- /** @var array A 2-d map overriding the server info by external storage cluster */
- private $templateOverridesByCluster;
-
- /** @var array An override array for all master servers */
- private $masterTemplateOverrides;
-
- /**
- * @var array|bool A map of section name to read-only message. Missing or
- * false for read/write
- */
- private $readOnlyBySection = array();
-
- // Other stuff
-
- /** @var array Load balancer factory configuration */
- private $conf;
-
- /** @var LoadBalancer[] */
- private $mainLBs = array();
-
- /** @var LoadBalancer[] */
- private $extLBs = array();
-
- /** @var string */
- private $lastWiki;
-
- /** @var string */
- private $lastSection;
-
- /**
- * @param array $conf
- * @throws MWException
- */
- public function __construct( array $conf ) {
- $this->chronProt = new ChronologyProtector;
- $this->conf = $conf;
- $required = array( 'sectionsByDB', 'sectionLoads', 'serverTemplate' );
- $optional = array( 'groupLoadsBySection', 'groupLoadsByDB', 'hostsByName',
- 'externalLoads', 'externalTemplateOverrides', 'templateOverridesByServer',
- 'templateOverridesByCluster', 'masterTemplateOverrides',
- 'readOnlyBySection' );
-
- foreach ( $required as $key ) {
- if ( !isset( $conf[$key] ) ) {
- throw new MWException( __CLASS__ . ": $key is required in configuration" );
- }
- $this->$key = $conf[$key];
- }
-
- foreach ( $optional as $key ) {
- if ( isset( $conf[$key] ) ) {
- $this->$key = $conf[$key];
- }
- }
-
- // Check for read-only mode
- $section = $this->getSectionForWiki();
- if ( !empty( $this->readOnlyBySection[$section] ) ) {
- global $wgReadOnly;
- $wgReadOnly = $this->readOnlyBySection[$section];
- }
- }
-
- /**
- * @param bool|string $wiki
- * @return string
- */
- private function getSectionForWiki( $wiki = false ) {
- if ( $this->lastWiki === $wiki ) {
- return $this->lastSection;
- }
- list( $dbName, ) = $this->getDBNameAndPrefix( $wiki );
- if ( isset( $this->sectionsByDB[$dbName] ) ) {
- $section = $this->sectionsByDB[$dbName];
- } else {
- $section = 'DEFAULT';
- }
- $this->lastSection = $section;
- $this->lastWiki = $wiki;
-
- return $section;
- }
-
- /**
- * @param bool|string $wiki
- * @return LoadBalancer
- */
- public function newMainLB( $wiki = false ) {
- list( $dbName, ) = $this->getDBNameAndPrefix( $wiki );
- $section = $this->getSectionForWiki( $wiki );
- $groupLoads = array();
- if ( isset( $this->groupLoadsByDB[$dbName] ) ) {
- $groupLoads = $this->groupLoadsByDB[$dbName];
- }
-
- if ( isset( $this->groupLoadsBySection[$section] ) ) {
- $groupLoads = array_merge_recursive( $groupLoads, $this->groupLoadsBySection[$section] );
- }
-
- return $this->newLoadBalancer(
- $this->serverTemplate,
- $this->sectionLoads[$section],
- $groupLoads
- );
- }
-
- /**
- * @param bool|string $wiki
- * @return LoadBalancer
- */
- public function getMainLB( $wiki = false ) {
- $section = $this->getSectionForWiki( $wiki );
- if ( !isset( $this->mainLBs[$section] ) ) {
- $lb = $this->newMainLB( $wiki );
- $lb->parentInfo( array( 'id' => "main-$section" ) );
- $this->chronProt->initLB( $lb );
- $this->mainLBs[$section] = $lb;
- }
-
- return $this->mainLBs[$section];
- }
-
- /**
- * @param string $cluster
- * @param bool|string $wiki
- * @throws MWException
- * @return LoadBalancer
- */
- protected function newExternalLB( $cluster, $wiki = false ) {
- if ( !isset( $this->externalLoads[$cluster] ) ) {
- throw new MWException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
- }
- $template = $this->serverTemplate;
- if ( isset( $this->externalTemplateOverrides ) ) {
- $template = $this->externalTemplateOverrides + $template;
- }
- if ( isset( $this->templateOverridesByCluster[$cluster] ) ) {
- $template = $this->templateOverridesByCluster[$cluster] + $template;
- }
-
- return $this->newLoadBalancer( $template, $this->externalLoads[$cluster], array() );
- }
-
- /**
- * @param string $cluster External storage cluster, or false for core
- * @param bool|string $wiki Wiki ID, or false for the current wiki
- * @return LoadBalancer
- */
- public function &getExternalLB( $cluster, $wiki = false ) {
- if ( !isset( $this->extLBs[$cluster] ) ) {
- $this->extLBs[$cluster] = $this->newExternalLB( $cluster, $wiki );
- $this->extLBs[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
- $this->chronProt->initLB( $this->extLBs[$cluster] );
- }
-
- return $this->extLBs[$cluster];
- }
-
- /**
- * Make a new load balancer object based on template and load array
- *
- * @param array $template
- * @param array $loads
- * @param array $groupLoads
- * @return LoadBalancer
- */
- private function newLoadBalancer( $template, $loads, $groupLoads ) {
- $servers = $this->makeServerArray( $template, $loads, $groupLoads );
- $lb = new LoadBalancer( array(
- 'servers' => $servers,
- ) );
-
- return $lb;
- }
-
- /**
- * Make a server array as expected by LoadBalancer::__construct, using a template and load array
- *
- * @param array $template
- * @param array $loads
- * @param array $groupLoads
- * @return array
- */
- private function makeServerArray( $template, $loads, $groupLoads ) {
- $servers = array();
- $master = true;
- $groupLoadsByServer = $this->reindexGroupLoads( $groupLoads );
- foreach ( $groupLoadsByServer as $server => $stuff ) {
- if ( !isset( $loads[$server] ) ) {
- $loads[$server] = 0;
- }
- }
- foreach ( $loads as $serverName => $load ) {
- $serverInfo = $template;
- if ( $master ) {
- $serverInfo['master'] = true;
- if ( isset( $this->masterTemplateOverrides ) ) {
- $serverInfo = $this->masterTemplateOverrides + $serverInfo;
- }
- $master = false;
- }
- if ( isset( $this->templateOverridesByServer[$serverName] ) ) {
- $serverInfo = $this->templateOverridesByServer[$serverName] + $serverInfo;
- }
- if ( isset( $groupLoadsByServer[$serverName] ) ) {
- $serverInfo['groupLoads'] = $groupLoadsByServer[$serverName];
- }
- if ( isset( $this->hostsByName[$serverName] ) ) {
- $serverInfo['host'] = $this->hostsByName[$serverName];
- } else {
- $serverInfo['host'] = $serverName;
- }
- $serverInfo['hostName'] = $serverName;
- $serverInfo['load'] = $load;
- $servers[] = $serverInfo;
- }
-
- return $servers;
- }
-
- /**
- * Take a group load array indexed by group then server, and reindex it by server then group
- * @param array $groupLoads
- * @return array
- */
- private function reindexGroupLoads( $groupLoads ) {
- $reindexed = array();
- foreach ( $groupLoads as $group => $loads ) {
- foreach ( $loads as $server => $load ) {
- $reindexed[$server][$group] = $load;
- }
- }
-
- return $reindexed;
- }
-
- /**
- * Get the database name and prefix based on the wiki ID
- * @param bool|string $wiki
- * @return array
- */
- private function getDBNameAndPrefix( $wiki = false ) {
- if ( $wiki === false ) {
- global $wgDBname, $wgDBprefix;
-
- return array( $wgDBname, $wgDBprefix );
- } else {
- return wfSplitWikiID( $wiki );
- }
- }
-
- /**
- * Execute a function for each tracked load balancer
- * The callback is called with the load balancer as the first parameter,
- * and $params passed as the subsequent parameters.
- * @param callable $callback
- * @param array $params
- */
- public function forEachLB( $callback, array $params = array() ) {
- foreach ( $this->mainLBs as $lb ) {
- call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
- }
- foreach ( $this->extLBs as $lb ) {
- call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
- }
- }
-
- public function shutdown() {
- foreach ( $this->mainLBs as $lb ) {
- $this->chronProt->shutdownLB( $lb );
- }
- foreach ( $this->extLBs as $extLB ) {
- $this->chronProt->shutdownLB( $extLB );
- }
- $this->chronProt->shutdown();
- $this->commitMasterChanges();
- }
-}
+++ /dev/null
-<?php
-/**
- * Simple generator of database connections that always returns the same object.
- *
- * 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
- */
-
-/**
- * An LBFactory class that always returns a single database object.
- */
-class LBFactorySingle extends LBFactory {
- /** @var LoadBalancerSingle */
- private $lb;
-
- /**
- * @param array $conf An associative array with one member:
- * - connection: The DatabaseBase connection object
- */
- public function __construct( array $conf ) {
- $this->lb = new LoadBalancerSingle( $conf );
- }
-
- /**
- * @param bool|string $wiki
- * @return LoadBalancerSingle
- */
- public function newMainLB( $wiki = false ) {
- return $this->lb;
- }
-
- /**
- * @param bool|string $wiki
- * @return LoadBalancerSingle
- */
- public function getMainLB( $wiki = false ) {
- return $this->lb;
- }
-
- /**
- * @param string $cluster External storage cluster, or false for core
- * @param bool|string $wiki Wiki ID, or false for the current wiki
- * @return LoadBalancerSingle
- */
- protected function newExternalLB( $cluster, $wiki = false ) {
- return $this->lb;
- }
-
- /**
- * @param string $cluster External storage cluster, or false for core
- * @param bool|string $wiki Wiki ID, or false for the current wiki
- * @return LoadBalancerSingle
- */
- public function &getExternalLB( $cluster, $wiki = false ) {
- return $this->lb;
- }
-
- /**
- * @param string|callable $callback
- * @param array $params
- */
- public function forEachLB( $callback, array $params = array() ) {
- call_user_func_array( $callback, array_merge( array( $this->lb ), $params ) );
- }
-}
-
-/**
- * Helper class for LBFactorySingle.
- */
-class LoadBalancerSingle extends LoadBalancer {
- /** @var DatabaseBase */
- private $db;
-
- /**
- * @param array $params
- */
- public function __construct( array $params ) {
- $this->db = $params['connection'];
- parent::__construct( array( 'servers' => array( array(
- 'type' => $this->db->getType(),
- 'host' => $this->db->getServer(),
- 'dbname' => $this->db->getDBname(),
- 'load' => 1,
- ) ) ) );
- }
-
- /**
- *
- * @param string $server
- * @param bool $dbNameOverride
- *
- * @return DatabaseBase
- */
- protected function reallyOpenConnection( $server, $dbNameOverride = false ) {
- return $this->db;
- }
-}
+++ /dev/null
-<?php
-/**
- * Database load balancing.
- *
- * 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 load balancing object
- *
- * @todo document
- * @ingroup Database
- */
-class LoadBalancer {
- /** @var array[] Map of (server index => server config array) */
- private $mServers;
- /** @var array[] Map of (local/foreignUsed/foreignFree => server index => DatabaseBase array) */
- private $mConns;
- /** @var array Map of (server index => weight) */
- private $mLoads;
- /** @var array[] Map of (group => server index => weight) */
- private $mGroupLoads;
- /** @var bool Whether to disregard slave lag as a factor in slave selection */
- private $mAllowLagged;
- /** @var integer Seconds to spend waiting on slave lag to resolve */
- private $mWaitTimeout;
-
- /** @var array LBFactory information */
- private $mParentInfo;
- /** @var string The LoadMonitor subclass name */
- private $mLoadMonitorClass;
- /** @var LoadMonitor */
- private $mLoadMonitor;
-
- /** @var bool|DatabaseBase Database connection that caused a problem */
- private $mErrorConnection;
- /** @var integer The generic (not query grouped) slave index (of $mServers) */
- private $mReadIndex;
- /** @var bool|DBMasterPos False if not set */
- private $mWaitForPos;
- /** @var bool Whether the generic reader fell back to a lagged slave */
- private $mLaggedSlaveMode;
- /** @var string The last DB selection or connection error */
- private $mLastError = 'Unknown error';
- /** @var integer Total connections opened */
- private $connsOpened = 0;
-
- /** @var integer Warn when this many connection are held */
- const CONN_HELD_WARN_THRESHOLD = 10;
-
- /**
- * @param array $params Array with keys:
- * servers Required. Array of server info structures.
- * loadMonitor Name of a class used to fetch server lag and load.
- * @throws MWException
- */
- public function __construct( array $params ) {
- if ( !isset( $params['servers'] ) ) {
- throw new MWException( __CLASS__ . ': missing servers parameter' );
- }
- $this->mServers = $params['servers'];
- $this->mWaitTimeout = 10;
-
- $this->mReadIndex = -1;
- $this->mWriteIndex = -1;
- $this->mConns = array(
- 'local' => array(),
- 'foreignUsed' => array(),
- 'foreignFree' => array() );
- $this->mLoads = array();
- $this->mWaitForPos = false;
- $this->mLaggedSlaveMode = false;
- $this->mErrorConnection = false;
- $this->mAllowLagged = false;
-
- if ( isset( $params['loadMonitor'] ) ) {
- $this->mLoadMonitorClass = $params['loadMonitor'];
- } else {
- $master = reset( $params['servers'] );
- if ( isset( $master['type'] ) && $master['type'] === 'mysql' ) {
- $this->mLoadMonitorClass = 'LoadMonitorMySQL';
- } else {
- $this->mLoadMonitorClass = 'LoadMonitorNull';
- }
- }
-
- foreach ( $params['servers'] as $i => $server ) {
- $this->mLoads[$i] = $server['load'];
- if ( isset( $server['groupLoads'] ) ) {
- foreach ( $server['groupLoads'] as $group => $ratio ) {
- if ( !isset( $this->mGroupLoads[$group] ) ) {
- $this->mGroupLoads[$group] = array();
- }
- $this->mGroupLoads[$group][$i] = $ratio;
- }
- }
- }
- }
-
- /**
- * Get a LoadMonitor instance
- *
- * @return LoadMonitor
- */
- private function getLoadMonitor() {
- if ( !isset( $this->mLoadMonitor ) ) {
- $class = $this->mLoadMonitorClass;
- $this->mLoadMonitor = new $class( $this );
- }
-
- return $this->mLoadMonitor;
- }
-
- /**
- * Get or set arbitrary data used by the parent object, usually an LBFactory
- * @param mixed $x
- * @return mixed
- */
- public function parentInfo( $x = null ) {
- return wfSetVar( $this->mParentInfo, $x );
- }
-
- /**
- * Given an array of non-normalised probabilities, this function will select
- * an element and return the appropriate key
- *
- * @deprecated since 1.21, use ArrayUtils::pickRandom()
- *
- * @param array $weights
- * @return bool|int|string
- */
- public function pickRandom( array $weights ) {
- return ArrayUtils::pickRandom( $weights );
- }
-
- /**
- * @param array $loads
- * @param bool|string $wiki Wiki to get non-lagged for
- * @param float $maxLag Restrict the maximum allowed lag to this many seconds
- * @return bool|int|string
- */
- private function getRandomNonLagged( array $loads, $wiki = false, $maxLag = INF ) {
- $lags = $this->getLagTimes( $wiki );
-
- # Unset excessively lagged servers
- foreach ( $lags as $i => $lag ) {
- if ( $i != 0 ) {
- $maxServerLag = $maxLag;
- if ( isset( $this->mServers[$i]['max lag'] ) ) {
- $maxServerLag = min( $maxServerLag, $this->mServers[$i]['max lag'] );
- }
- if ( $lag === false ) {
- wfDebugLog( 'replication', "Server #$i is not replicating" );
- unset( $loads[$i] );
- } elseif ( $lag > $maxServerLag ) {
- wfDebugLog( 'replication', "Server #$i is excessively lagged ($lag seconds)" );
- unset( $loads[$i] );
- }
- }
- }
-
- # Find out if all the slaves with non-zero load are lagged
- $sum = 0;
- foreach ( $loads as $load ) {
- $sum += $load;
- }
- if ( $sum == 0 ) {
- # No appropriate DB servers except maybe the master and some slaves with zero load
- # Do NOT use the master
- # Instead, this function will return false, triggering read-only mode,
- # and a lagged slave will be used instead.
- return false;
- }
-
- if ( count( $loads ) == 0 ) {
- return false;
- }
-
- #wfDebugLog( 'connect', var_export( $loads, true ) );
-
- # Return a random representative of the remainder
- return ArrayUtils::pickRandom( $loads );
- }
-
- /**
- * Get the index of the reader connection, which may be a slave
- * This takes into account load ratios and lag times. It should
- * always return a consistent index during a given invocation
- *
- * Side effect: opens connections to databases
- * @param string|bool $group Query group, or false for the generic reader
- * @param string|bool $wiki Wiki ID, or false for the current wiki
- * @throws MWException
- * @return bool|int|string
- */
- public function getReaderIndex( $group = false, $wiki = false ) {
- global $wgDBtype;
-
- # @todo FIXME: For now, only go through all this for mysql databases
- if ( $wgDBtype != 'mysql' ) {
- return $this->getWriterIndex();
- }
-
- if ( count( $this->mServers ) == 1 ) {
- # Skip the load balancing if there's only one server
- return 0;
- } elseif ( $group === false && $this->mReadIndex >= 0 ) {
- # Shortcut if generic reader exists already
- return $this->mReadIndex;
- }
-
- # Find the relevant load array
- if ( $group !== false ) {
- if ( isset( $this->mGroupLoads[$group] ) ) {
- $nonErrorLoads = $this->mGroupLoads[$group];
- } else {
- # No loads for this group, return false and the caller can use some other group
- wfDebug( __METHOD__ . ": no loads for group $group\n" );
-
- return false;
- }
- } else {
- $nonErrorLoads = $this->mLoads;
- }
-
- if ( !count( $nonErrorLoads ) ) {
- throw new MWException( "Empty server array given to LoadBalancer" );
- }
-
- # Scale the configured load ratios according to the dynamic load (if the load monitor supports it)
- $this->getLoadMonitor()->scaleLoads( $nonErrorLoads, $group, $wiki );
-
- $laggedSlaveMode = false;
-
- # No server found yet
- $i = false;
- # First try quickly looking through the available servers for a server that
- # meets our criteria
- $currentLoads = $nonErrorLoads;
- while ( count( $currentLoads ) ) {
- if ( $this->mAllowLagged || $laggedSlaveMode ) {
- $i = ArrayUtils::pickRandom( $currentLoads );
- } else {
- $i = false;
- if ( $this->mWaitForPos && $this->mWaitForPos->asOfTime() ) {
- # ChronologyProtecter causes mWaitForPos to be set via sessions.
- # This triggers doWait() after connect, so it's especially good to
- # avoid lagged servers so as to avoid just blocking in that method.
- $ago = microtime( true ) - $this->mWaitForPos->asOfTime();
- # Aim for <= 1 second of waiting (being too picky can backfire)
- $i = $this->getRandomNonLagged( $currentLoads, $wiki, $ago + 1 );
- }
- if ( $i === false ) {
- # Any server with less lag than it's 'max lag' param is preferable
- $i = $this->getRandomNonLagged( $currentLoads, $wiki );
- }
- if ( $i === false && count( $currentLoads ) != 0 ) {
- # All slaves lagged. Switch to read-only mode
- wfDebugLog( 'replication', "All slaves lagged. Switch to read-only mode" );
- $i = ArrayUtils::pickRandom( $currentLoads );
- $laggedSlaveMode = true;
- }
- }
-
- if ( $i === false ) {
- # pickRandom() returned false
- # This is permanent and means the configuration or the load monitor
- # wants us to return false.
- wfDebugLog( 'connect', __METHOD__ . ": pickRandom() returned false" );
-
- return false;
- }
-
- $serverName = $this->getServerName( $i );
- wfDebugLog( 'connect', __METHOD__ . ": Using reader #$i: $serverName..." );
-
- $conn = $this->openConnection( $i, $wiki );
- if ( !$conn ) {
- wfDebugLog( 'connect', __METHOD__ . ": Failed connecting to $i/$wiki" );
- unset( $nonErrorLoads[$i] );
- unset( $currentLoads[$i] );
- $i = false;
- continue;
- }
-
- // Decrement reference counter, we are finished with this connection.
- // It will be incremented for the caller later.
- if ( $wiki !== false ) {
- $this->reuseConnection( $conn );
- }
-
- # Return this server
- break;
- }
-
- # If all servers were down, quit now
- if ( !count( $nonErrorLoads ) ) {
- wfDebugLog( 'connect', "All servers down" );
- }
-
- if ( $i !== false ) {
- # Slave connection successful
- # Wait for the session master pos for a short time
- if ( $this->mWaitForPos && $i > 0 ) {
- if ( !$this->doWait( $i ) ) {
- $this->mServers[$i]['slave pos'] = $conn->getSlavePos();
- }
- }
- if ( $this->mReadIndex <= 0 && $this->mLoads[$i] > 0 && $group === false ) {
- $this->mReadIndex = $i;
- # Record if the generic reader index is in "lagged slave" mode
- if ( $laggedSlaveMode ) {
- $this->mLaggedSlaveMode = true;
- }
- }
- $serverName = $this->getServerName( $i );
- wfDebug( __METHOD__ . ": using server $serverName for group '$group'\n" );
- }
-
- return $i;
- }
-
- /**
- * Set the master wait position
- * If a DB_SLAVE connection has been opened already, waits
- * Otherwise sets a variable telling it to wait if such a connection is opened
- * @param DBMasterPos $pos
- */
- public function waitFor( $pos ) {
- $this->mWaitForPos = $pos;
- $i = $this->mReadIndex;
-
- if ( $i > 0 ) {
- if ( !$this->doWait( $i ) ) {
- $this->mServers[$i]['slave pos'] = $this->getAnyOpenConnection( $i )->getSlavePos();
- $this->mLaggedSlaveMode = true;
- }
- }
- }
-
- /**
- * Set the master wait position and wait for a "generic" slave to catch up to it
- *
- * This can be used a faster proxy for waitForAll()
- *
- * @param DBMasterPos $pos
- * @param int $timeout Max seconds to wait; default is mWaitTimeout
- * @return bool Success (able to connect and no timeouts reached)
- * @since 1.26
- */
- public function waitForOne( $pos, $timeout = null ) {
- $this->mWaitForPos = $pos;
-
- $i = $this->mReadIndex;
- if ( $i <= 0 ) {
- // Pick a generic slave if there isn't one yet
- $readLoads = $this->mLoads;
- unset( $readLoads[$this->getWriterIndex()] ); // slaves only
- $readLoads = array_filter( $readLoads ); // with non-zero load
- $i = ArrayUtils::pickRandom( $readLoads );
- }
-
- if ( $i > 0 ) {
- $ok = $this->doWait( $i, true, $timeout );
- } else {
- $ok = true; // no applicable loads
- }
-
- return $ok;
- }
-
- /**
- * Set the master wait position and wait for ALL slaves to catch up to it
- * @param DBMasterPos $pos
- * @param int $timeout Max seconds to wait; default is mWaitTimeout
- * @return bool Success (able to connect and no timeouts reached)
- */
- public function waitForAll( $pos, $timeout = null ) {
- $this->mWaitForPos = $pos;
- $serverCount = count( $this->mServers );
-
- $ok = true;
- for ( $i = 1; $i < $serverCount; $i++ ) {
- if ( $this->mLoads[$i] > 0 ) {
- $ok = $this->doWait( $i, true, $timeout ) && $ok;
- }
- }
-
- return $ok;
- }
-
- /**
- * Get any open connection to a given server index, local or foreign
- * Returns false if there is no connection open
- *
- * @param int $i
- * @return DatabaseBase|bool False on failure
- */
- public function getAnyOpenConnection( $i ) {
- foreach ( $this->mConns as $conns ) {
- if ( !empty( $conns[$i] ) ) {
- return reset( $conns[$i] );
- }
- }
-
- return false;
- }
-
- /**
- * Wait for a given slave to catch up to the master pos stored in $this
- * @param int $index Server index
- * @param bool $open Check the server even if a new connection has to be made
- * @param int $timeout Max seconds to wait; default is mWaitTimeout
- * @return bool
- */
- protected function doWait( $index, $open = false, $timeout = null ) {
- $close = false; // close the connection afterwards
-
- # Find a connection to wait on, creating one if needed and allowed
- $conn = $this->getAnyOpenConnection( $index );
- if ( !$conn ) {
- if ( !$open ) {
- wfDebug( __METHOD__ . ": no connection open\n" );
-
- return false;
- } else {
- $conn = $this->openConnection( $index, '' );
- if ( !$conn ) {
- wfDebug( __METHOD__ . ": failed to open connection\n" );
-
- return false;
- }
- // Avoid connection spam in waitForAll() when connections
- // are made just for the sake of doing this lag check.
- $close = true;
- }
- }
-
- wfDebug( __METHOD__ . ": Waiting for slave #$index to catch up...\n" );
- $timeout = $timeout ?: $this->mWaitTimeout;
- $result = $conn->masterPosWait( $this->mWaitForPos, $timeout );
-
- if ( $result == -1 || is_null( $result ) ) {
- # Timed out waiting for slave, use master instead
- $server = $server = $this->getServerName( $index );
- $msg = __METHOD__ . ": Timed out waiting on $server pos {$this->mWaitForPos}";
- wfDebug( "$msg\n" );
- wfDebugLog( 'DBPerformance', "$msg:\n" . wfBacktrace( true ) );
- $ok = false;
- } else {
- wfDebug( __METHOD__ . ": Done\n" );
- $ok = true;
- }
-
- if ( $close ) {
- $this->closeConnection( $conn );
- }
-
- return $ok;
- }
-
- /**
- * Get a connection by index
- * This is the main entry point for this class.
- *
- * @param int $i Server index
- * @param array|string|bool $groups Query group(s), or false for the generic reader
- * @param string|bool $wiki Wiki ID, or false for the current wiki
- *
- * @throws MWException
- * @return DatabaseBase
- */
- public function getConnection( $i, $groups = array(), $wiki = false ) {
- if ( $i === null || $i === false ) {
- throw new MWException( 'Attempt to call ' . __METHOD__ .
- ' with invalid server index' );
- }
-
- if ( $wiki === wfWikiID() ) {
- $wiki = false;
- }
-
- $groups = ( $groups === false || $groups === array() )
- ? array( false ) // check one "group": the generic pool
- : (array)$groups;
-
- $masterOnly = ( $i == DB_MASTER || $i == $this->getWriterIndex() );
- $oldConnsOpened = $this->connsOpened; // connections open now
-
- if ( $i == DB_MASTER ) {
- $i = $this->getWriterIndex();
- } else {
- # Try to find an available server in any the query groups (in order)
- foreach ( $groups as $group ) {
- $groupIndex = $this->getReaderIndex( $group, $wiki );
- if ( $groupIndex !== false ) {
- $i = $groupIndex;
- break;
- }
- }
- }
-
- # Operation-based index
- if ( $i == DB_SLAVE ) {
- $this->mLastError = 'Unknown error'; // reset error string
- # Try the general server pool if $groups are unavailable.
- $i = in_array( false, $groups, true )
- ? false // don't bother with this if that is what was tried above
- : $this->getReaderIndex( false, $wiki );
- # Couldn't find a working server in getReaderIndex()?
- if ( $i === false ) {
- $this->mLastError = 'No working slave server: ' . $this->mLastError;
-
- return $this->reportConnectionError();
- }
- }
-
- # Now we have an explicit index into the servers array
- $conn = $this->openConnection( $i, $wiki );
- if ( !$conn ) {
- return $this->reportConnectionError();
- }
-
- # Profile any new connections that happen
- if ( $this->connsOpened > $oldConnsOpened ) {
- $host = $conn->getServer();
- $dbname = $conn->getDBname();
- $trxProf = Profiler::instance()->getTransactionProfiler();
- $trxProf->recordConnection( $host, $dbname, $masterOnly );
- }
-
- return $conn;
- }
-
- /**
- * Mark a foreign connection as being available for reuse under a different
- * DB name or prefix. This mechanism is reference-counted, and must be called
- * the same number of times as getConnection() to work.
- *
- * @param DatabaseBase $conn
- * @throws MWException
- */
- public function reuseConnection( $conn ) {
- $serverIndex = $conn->getLBInfo( 'serverIndex' );
- $refCount = $conn->getLBInfo( 'foreignPoolRefCount' );
- if ( $serverIndex === null || $refCount === null ) {
- wfDebug( __METHOD__ . ": this connection was not opened as a foreign connection\n" );
-
- /**
- * This can happen in code like:
- * foreach ( $dbs as $db ) {
- * $conn = $lb->getConnection( DB_SLAVE, array(), $db );
- * ...
- * $lb->reuseConnection( $conn );
- * }
- * When a connection to the local DB is opened in this way, reuseConnection()
- * should be ignored
- */
-
- return;
- }
-
- $dbName = $conn->getDBname();
- $prefix = $conn->tablePrefix();
- if ( strval( $prefix ) !== '' ) {
- $wiki = "$dbName-$prefix";
- } else {
- $wiki = $dbName;
- }
- if ( $this->mConns['foreignUsed'][$serverIndex][$wiki] !== $conn ) {
- throw new MWException( __METHOD__ . ": connection not found, has " .
- "the connection been freed already?" );
- }
- $conn->setLBInfo( 'foreignPoolRefCount', --$refCount );
- if ( $refCount <= 0 ) {
- $this->mConns['foreignFree'][$serverIndex][$wiki] = $conn;
- unset( $this->mConns['foreignUsed'][$serverIndex][$wiki] );
- wfDebug( __METHOD__ . ": freed connection $serverIndex/$wiki\n" );
- } else {
- wfDebug( __METHOD__ . ": reference count for $serverIndex/$wiki reduced to $refCount\n" );
- }
- }
-
- /**
- * Get a database connection handle reference
- *
- * The handle's methods wrap simply wrap those of a DatabaseBase handle
- *
- * @see LoadBalancer::getConnection() for parameter information
- *
- * @param int $db
- * @param array|string|bool $groups Query group(s), or false for the generic reader
- * @param string|bool $wiki Wiki ID, or false for the current wiki
- * @return DBConnRef
- */
- public function getConnectionRef( $db, $groups = array(), $wiki = false ) {
- return new DBConnRef( $this, $this->getConnection( $db, $groups, $wiki ) );
- }
-
- /**
- * Get a database connection handle reference without connecting yet
- *
- * The handle's methods wrap simply wrap those of a DatabaseBase handle
- *
- * @see LoadBalancer::getConnection() for parameter information
- *
- * @param int $db
- * @param array|string|bool $groups Query group(s), or false for the generic reader
- * @param string|bool $wiki Wiki ID, or false for the current wiki
- * @return DBConnRef
- */
- public function getLazyConnectionRef( $db, $groups = array(), $wiki = false ) {
- return new DBConnRef( $this, array( $db, $groups, $wiki ) );
- }
-
- /**
- * Open a connection to the server given by the specified index
- * Index must be an actual index into the array.
- * If the server is already open, returns it.
- *
- * On error, returns false, and the connection which caused the
- * error will be available via $this->mErrorConnection.
- *
- * @param int $i Server index
- * @param string|bool $wiki Wiki ID, or false for the current wiki
- * @return DatabaseBase
- *
- * @access private
- */
- public function openConnection( $i, $wiki = false ) {
- if ( $wiki !== false ) {
- $conn = $this->openForeignConnection( $i, $wiki );
- } elseif ( isset( $this->mConns['local'][$i][0] ) ) {
- $conn = $this->mConns['local'][$i][0];
- } else {
- $server = $this->mServers[$i];
- $server['serverIndex'] = $i;
- $conn = $this->reallyOpenConnection( $server, false );
- $serverName = $this->getServerName( $i );
- if ( $conn->isOpen() ) {
- wfDebug( "Connected to database $i at $serverName\n" );
- $this->mConns['local'][$i][0] = $conn;
- } else {
- wfDebug( "Failed to connect to database $i at $serverName\n" );
- $this->mErrorConnection = $conn;
- $conn = false;
- }
- }
-
- if ( $conn && !$conn->isOpen() ) {
- // Connection was made but later unrecoverably lost for some reason.
- // Do not return a handle that will just throw exceptions on use,
- // but let the calling code (e.g. getReaderIndex) try another server.
- // See DatabaseMyslBase::ping() for how this can happen.
- $this->mErrorConnection = $conn;
- $conn = false;
- }
-
- return $conn;
- }
-
- /**
- * Open a connection to a foreign DB, or return one if it is already open.
- *
- * Increments a reference count on the returned connection which locks the
- * connection to the requested wiki. This reference count can be
- * decremented by calling reuseConnection().
- *
- * If a connection is open to the appropriate server already, but with the wrong
- * database, it will be switched to the right database and returned, as long as
- * it has been freed first with reuseConnection().
- *
- * On error, returns false, and the connection which caused the
- * error will be available via $this->mErrorConnection.
- *
- * @param int $i Server index
- * @param string $wiki Wiki ID to open
- * @return DatabaseBase
- */
- private function openForeignConnection( $i, $wiki ) {
- list( $dbName, $prefix ) = wfSplitWikiID( $wiki );
- if ( isset( $this->mConns['foreignUsed'][$i][$wiki] ) ) {
- // Reuse an already-used connection
- $conn = $this->mConns['foreignUsed'][$i][$wiki];
- wfDebug( __METHOD__ . ": reusing connection $i/$wiki\n" );
- } elseif ( isset( $this->mConns['foreignFree'][$i][$wiki] ) ) {
- // Reuse a free connection for the same wiki
- $conn = $this->mConns['foreignFree'][$i][$wiki];
- unset( $this->mConns['foreignFree'][$i][$wiki] );
- $this->mConns['foreignUsed'][$i][$wiki] = $conn;
- wfDebug( __METHOD__ . ": reusing free connection $i/$wiki\n" );
- } elseif ( !empty( $this->mConns['foreignFree'][$i] ) ) {
- // Reuse a connection from another wiki
- $conn = reset( $this->mConns['foreignFree'][$i] );
- $oldWiki = key( $this->mConns['foreignFree'][$i] );
-
- // The empty string as a DB name means "don't care".
- // DatabaseMysqlBase::open() already handle this on connection.
- if ( $dbName !== '' && !$conn->selectDB( $dbName ) ) {
- $this->mLastError = "Error selecting database $dbName on server " .
- $conn->getServer() . " from client host " . wfHostname() . "\n";
- $this->mErrorConnection = $conn;
- $conn = false;
- } else {
- $conn->tablePrefix( $prefix );
- unset( $this->mConns['foreignFree'][$i][$oldWiki] );
- $this->mConns['foreignUsed'][$i][$wiki] = $conn;
- wfDebug( __METHOD__ . ": reusing free connection from $oldWiki for $wiki\n" );
- }
- } else {
- // Open a new connection
- $server = $this->mServers[$i];
- $server['serverIndex'] = $i;
- $server['foreignPoolRefCount'] = 0;
- $server['foreign'] = true;
- $conn = $this->reallyOpenConnection( $server, $dbName );
- if ( !$conn->isOpen() ) {
- wfDebug( __METHOD__ . ": error opening connection for $i/$wiki\n" );
- $this->mErrorConnection = $conn;
- $conn = false;
- } else {
- $conn->tablePrefix( $prefix );
- $this->mConns['foreignUsed'][$i][$wiki] = $conn;
- wfDebug( __METHOD__ . ": opened new connection for $i/$wiki\n" );
- }
- }
-
- // Increment reference count
- if ( $conn ) {
- $refCount = $conn->getLBInfo( 'foreignPoolRefCount' );
- $conn->setLBInfo( 'foreignPoolRefCount', $refCount + 1 );
- }
-
- return $conn;
- }
-
- /**
- * Test if the specified index represents an open connection
- *
- * @param int $index Server index
- * @access private
- * @return bool
- */
- private function isOpen( $index ) {
- if ( !is_integer( $index ) ) {
- return false;
- }
-
- return (bool)$this->getAnyOpenConnection( $index );
- }
-
- /**
- * Really opens a connection. Uncached.
- * Returns a Database object whether or not the connection was successful.
- * @access private
- *
- * @param array $server
- * @param bool $dbNameOverride
- * @throws MWException
- * @return DatabaseBase
- */
- protected function reallyOpenConnection( $server, $dbNameOverride = false ) {
- if ( !is_array( $server ) ) {
- throw new MWException( 'You must update your load-balancing configuration. ' .
- 'See DefaultSettings.php entry for $wgDBservers.' );
- }
-
- if ( $dbNameOverride !== false ) {
- $server['dbname'] = $dbNameOverride;
- }
-
- // Log when many connection are made on requests
- if ( ++$this->connsOpened >= self::CONN_HELD_WARN_THRESHOLD ) {
- $masterAddr = $this->getServerName( 0 );
- wfDebugLog( 'DBPerformance', __METHOD__ . ": " .
- "{$this->connsOpened}+ connections made (master=$masterAddr)\n" .
- wfBacktrace( true ) );
- }
-
- # Create object
- try {
- $db = DatabaseBase::factory( $server['type'], $server );
- } catch ( DBConnectionError $e ) {
- // FIXME: This is probably the ugliest thing I have ever done to
- // PHP. I'm half-expecting it to segfault, just out of disgust. -- TS
- $db = $e->db;
- }
-
- $db->setLBInfo( $server );
- if ( isset( $server['fakeSlaveLag'] ) ) {
- $db->setFakeSlaveLag( $server['fakeSlaveLag'] );
- }
- if ( isset( $server['fakeMaster'] ) ) {
- $db->setFakeMaster( true );
- }
-
- return $db;
- }
-
- /**
- * @throws DBConnectionError
- * @return bool
- */
- private function reportConnectionError() {
- $conn = $this->mErrorConnection; // The connection which caused the error
- $context = array(
- 'method' => __METHOD__,
- 'last_error' => $this->mLastError,
- );
-
- if ( !is_object( $conn ) ) {
- // No last connection, probably due to all servers being too busy
- wfLogDBError(
- "LB failure with no last connection. Connection error: {last_error}",
- $context
- );
-
- // If all servers were busy, mLastError will contain something sensible
- throw new DBConnectionError( null, $this->mLastError );
- } else {
- $context['db_server'] = $conn->getProperty( 'mServer' );
- wfLogDBError(
- "Connection error: {last_error} ({db_server})",
- $context
- );
- $conn->reportConnectionError( "{$this->mLastError} ({$context['db_server']})" ); // throws DBConnectionError
- }
-
- return false; /* not reached */
- }
-
- /**
- * @return int
- * @since 1.26
- */
- public function getWriterIndex() {
- return 0;
- }
-
- /**
- * Returns true if the specified index is a valid server index
- *
- * @param string $i
- * @return bool
- */
- public function haveIndex( $i ) {
- return array_key_exists( $i, $this->mServers );
- }
-
- /**
- * Returns true if the specified index is valid and has non-zero load
- *
- * @param string $i
- * @return bool
- */
- public function isNonZeroLoad( $i ) {
- return array_key_exists( $i, $this->mServers ) && $this->mLoads[$i] != 0;
- }
-
- /**
- * Get the number of defined servers (not the number of open connections)
- *
- * @return int
- */
- public function getServerCount() {
- return count( $this->mServers );
- }
-
- /**
- * Get the host name or IP address of the server with the specified index
- * Prefer a readable name if available.
- * @param string $i
- * @return string
- */
- public function getServerName( $i ) {
- if ( isset( $this->mServers[$i]['hostName'] ) ) {
- $name = $this->mServers[$i]['hostName'];
- } elseif ( isset( $this->mServers[$i]['host'] ) ) {
- $name = $this->mServers[$i]['host'];
- } else {
- $name = '';
- }
-
- return ( $name != '' ) ? $name : 'localhost';
- }
-
- /**
- * Return the server info structure for a given index, or false if the index is invalid.
- * @param int $i
- * @return array|bool
- */
- public function getServerInfo( $i ) {
- if ( isset( $this->mServers[$i] ) ) {
- return $this->mServers[$i];
- } else {
- return false;
- }
- }
-
- /**
- * Sets the server info structure for the given index. Entry at index $i
- * is created if it doesn't exist
- * @param int $i
- * @param array $serverInfo
- */
- public function setServerInfo( $i, array $serverInfo ) {
- $this->mServers[$i] = $serverInfo;
- }
-
- /**
- * Get the current master position for chronology control purposes
- * @return mixed
- */
- public function getMasterPos() {
- # If this entire request was served from a slave without opening a connection to the
- # master (however unlikely that may be), then we can fetch the position from the slave.
- $masterConn = $this->getAnyOpenConnection( 0 );
- if ( !$masterConn ) {
- $serverCount = count( $this->mServers );
- for ( $i = 1; $i < $serverCount; $i++ ) {
- $conn = $this->getAnyOpenConnection( $i );
- if ( $conn ) {
- wfDebug( "Master pos fetched from slave\n" );
-
- return $conn->getSlavePos();
- }
- }
- } else {
- wfDebug( "Master pos fetched from master\n" );
-
- return $masterConn->getMasterPos();
- }
-
- return false;
- }
-
- /**
- * Close all open connections
- */
- public function closeAll() {
- foreach ( $this->mConns as $conns2 ) {
- foreach ( $conns2 as $conns3 ) {
- /** @var DatabaseBase $conn */
- foreach ( $conns3 as $conn ) {
- $conn->close();
- }
- }
- }
- $this->mConns = array(
- 'local' => array(),
- 'foreignFree' => array(),
- 'foreignUsed' => array(),
- );
- $this->connsOpened = 0;
- }
-
- /**
- * Close a connection
- * Using this function makes sure the LoadBalancer knows the connection is closed.
- * If you use $conn->close() directly, the load balancer won't update its state.
- * @param DatabaseBase $conn
- */
- public function closeConnection( $conn ) {
- $done = false;
- foreach ( $this->mConns as $i1 => $conns2 ) {
- foreach ( $conns2 as $i2 => $conns3 ) {
- foreach ( $conns3 as $i3 => $candidateConn ) {
- if ( $conn === $candidateConn ) {
- $conn->close();
- unset( $this->mConns[$i1][$i2][$i3] );
- --$this->connsOpened;
- $done = true;
- break;
- }
- }
- }
- }
- if ( !$done ) {
- $conn->close();
- }
- }
-
- /**
- * Commit transactions on all open connections
- */
- public function commitAll() {
- foreach ( $this->mConns as $conns2 ) {
- foreach ( $conns2 as $conns3 ) {
- /** @var DatabaseBase[] $conns3 */
- foreach ( $conns3 as $conn ) {
- if ( $conn->trxLevel() ) {
- $conn->commit( __METHOD__, 'flush' );
- }
- }
- }
- }
- }
-
- /**
- * Issue COMMIT only on master, only if queries were done on connection
- */
- public function commitMasterChanges() {
- $masterIndex = $this->getWriterIndex();
- foreach ( $this->mConns as $conns2 ) {
- if ( empty( $conns2[$masterIndex] ) ) {
- continue;
- }
- /** @var DatabaseBase $conn */
- foreach ( $conns2[$masterIndex] as $conn ) {
- if ( $conn->trxLevel() && $conn->writesOrCallbacksPending() ) {
- $conn->commit( __METHOD__, 'flush' );
- }
- }
- }
- }
-
- /**
- * Issue ROLLBACK only on master, only if queries were done on connection
- * @since 1.23
- */
- public function rollbackMasterChanges() {
- $failedServers = array();
-
- $masterIndex = $this->getWriterIndex();
- foreach ( $this->mConns as $conns2 ) {
- if ( empty( $conns2[$masterIndex] ) ) {
- continue;
- }
- /** @var DatabaseBase $conn */
- foreach ( $conns2[$masterIndex] as $conn ) {
- if ( $conn->trxLevel() && $conn->writesOrCallbacksPending() ) {
- try {
- $conn->rollback( __METHOD__, 'flush' );
- } catch ( DBError $e ) {
- MWExceptionHandler::logException( $e );
- $failedServers[] = $conn->getServer();
- }
- }
- }
- }
-
- if ( $failedServers ) {
- throw new DBExpectedError( null, "Rollback failed on server(s) " .
- implode( ', ', array_unique( $failedServers ) ) );
- }
- }
-
- /**
- * @return bool Whether a master connection is already open
- * @since 1.24
- */
- public function hasMasterConnection() {
- return $this->isOpen( $this->getWriterIndex() );
- }
-
- /**
- * Determine if there are pending changes in a transaction by this thread
- * @since 1.23
- * @return bool
- */
- public function hasMasterChanges() {
- $masterIndex = $this->getWriterIndex();
- foreach ( $this->mConns as $conns2 ) {
- if ( empty( $conns2[$masterIndex] ) ) {
- continue;
- }
- /** @var DatabaseBase $conn */
- foreach ( $conns2[$masterIndex] as $conn ) {
- if ( $conn->trxLevel() && $conn->writesOrCallbacksPending() ) {
- return true;
- }
- }
- }
- return false;
- }
-
- /**
- * Get the timestamp of the latest write query done by this thread
- * @since 1.25
- * @return float|bool UNIX timestamp or false
- */
- public function lastMasterChangeTimestamp() {
- $lastTime = false;
- $masterIndex = $this->getWriterIndex();
- foreach ( $this->mConns as $conns2 ) {
- if ( empty( $conns2[$masterIndex] ) ) {
- continue;
- }
- /** @var DatabaseBase $conn */
- foreach ( $conns2[$masterIndex] as $conn ) {
- $lastTime = max( $lastTime, $conn->lastDoneWrites() );
- }
- }
- return $lastTime;
- }
-
- /**
- * Check if this load balancer object had any recent or still
- * pending writes issued against it by this PHP thread
- *
- * @param float $age How many seconds ago is "recent" [defaults to mWaitTimeout]
- * @return bool
- * @since 1.25
- */
- public function hasOrMadeRecentMasterChanges( $age = null ) {
- $age = ( $age === null ) ? $this->mWaitTimeout : $age;
-
- return ( $this->hasMasterChanges()
- || $this->lastMasterChangeTimestamp() > microtime( true ) - $age );
- }
-
- /**
- * @param mixed $value
- * @return mixed
- */
- public function waitTimeout( $value = null ) {
- return wfSetVar( $this->mWaitTimeout, $value );
- }
-
- /**
- * @return bool Whether the generic connection for reads is highly "lagged"
- */
- public function getLaggedSlaveMode() {
- # Get a generic reader connection
- $this->getConnection( DB_SLAVE );
-
- return $this->mLaggedSlaveMode;
- }
-
- /**
- * Disables/enables lag checks
- * @param null|bool $mode
- * @return bool
- */
- public function allowLagged( $mode = null ) {
- if ( $mode === null ) {
- return $this->mAllowLagged;
- }
- $this->mAllowLagged = $mode;
-
- return $this->mAllowLagged;
- }
-
- /**
- * @return bool
- */
- public function pingAll() {
- $success = true;
- foreach ( $this->mConns as $conns2 ) {
- foreach ( $conns2 as $conns3 ) {
- /** @var DatabaseBase[] $conns3 */
- foreach ( $conns3 as $conn ) {
- if ( !$conn->ping() ) {
- $success = false;
- }
- }
- }
- }
-
- return $success;
- }
-
- /**
- * Call a function with each open connection object
- * @param callable $callback
- * @param array $params
- */
- public function forEachOpenConnection( $callback, array $params = array() ) {
- foreach ( $this->mConns as $conns2 ) {
- foreach ( $conns2 as $conns3 ) {
- foreach ( $conns3 as $conn ) {
- $mergedParams = array_merge( array( $conn ), $params );
- call_user_func_array( $callback, $mergedParams );
- }
- }
- }
- }
-
- /**
- * Get the hostname and lag time of the most-lagged slave
- *
- * This is useful for maintenance scripts that need to throttle their updates.
- * May attempt to open connections to slaves on the default DB. If there is
- * no lag, the maximum lag will be reported as -1.
- *
- * @param bool|string $wiki Wiki ID, or false for the default database
- * @return array ( host, max lag, index of max lagged host )
- */
- public function getMaxLag( $wiki = false ) {
- $maxLag = -1;
- $host = '';
- $maxIndex = 0;
-
- if ( $this->getServerCount() <= 1 ) {
- return array( $host, $maxLag, $maxIndex ); // no replication = no lag
- }
-
- $lagTimes = $this->getLagTimes( $wiki );
- foreach ( $lagTimes as $i => $lag ) {
- if ( $lag > $maxLag ) {
- $maxLag = $lag;
- $host = $this->mServers[$i]['host'];
- $maxIndex = $i;
- }
- }
-
- return array( $host, $maxLag, $maxIndex );
- }
-
- /**
- * Get lag time for each server
- *
- * Results are cached for a short time in memcached/process cache
- *
- * @param string|bool $wiki
- * @return int[] Map of (server index => seconds)
- */
- public function getLagTimes( $wiki = false ) {
- if ( $this->getServerCount() <= 1 ) {
- return array( 0 => 0 ); // no replication = no lag
- }
-
- # Send the request to the load monitor
- return $this->getLoadMonitor()->getLagTimes( array_keys( $this->mServers ), $wiki );
- }
-
- /**
- * Get the lag in seconds for a given connection, or zero if this load
- * balancer does not have replication enabled.
- *
- * This should be used in preference to Database::getLag() in cases where
- * replication may not be in use, since there is no way to determine if
- * replication is in use at the connection level without running
- * potentially restricted queries such as SHOW SLAVE STATUS. Using this
- * function instead of Database::getLag() avoids a fatal error in this
- * case on many installations.
- *
- * @param DatabaseBase $conn
- * @return int
- */
- public function safeGetLag( $conn ) {
- if ( $this->getServerCount() == 1 ) {
- return 0;
- } else {
- return $conn->getLag();
- }
- }
-
- /**
- * Clear the cache for slag lag delay times
- *
- * This is only used for testing
- */
- public function clearLagTimeCache() {
- $this->getLoadMonitor()->clearCaches();
- }
-}
+++ /dev/null
-<?php
-/**
- * Database load monitoring.
- *
- * 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
- */
-
-/**
- * An interface for database load monitoring
- *
- * @ingroup Database
- */
-interface LoadMonitor {
- /**
- * Construct a new LoadMonitor with a given LoadBalancer parent
- *
- * @param LoadBalancer $parent
- */
- public function __construct( $parent );
-
- /**
- * Perform pre-connection load ratio adjustment.
- * @param array $loads
- * @param string|bool $group The selected query group. Default: false
- * @param string|bool $wiki Default: false
- */
- public function scaleLoads( &$loads, $group = false, $wiki = false );
-
- /**
- * Return an estimate of replication lag for each server
- *
- * @param array $serverIndexes
- * @param string $wiki
- *
- * @return array Map of (server index => seconds)
- */
- public function getLagTimes( $serverIndexes, $wiki );
-}
-
-class LoadMonitorNull implements LoadMonitor {
- public function __construct( $parent ) {
- }
-
- public function scaleLoads( &$loads, $group = false, $wiki = false ) {
- }
-
- public function getLagTimes( $serverIndexes, $wiki ) {
- return array_fill_keys( $serverIndexes, 0 );
- }
-}
+++ /dev/null
-<?php
-/**
- * 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
- */
-
-/**
- * Basic MySQL load monitor with no external dependencies
- * Uses memcached to cache the replication lag for a short time
- *
- * @ingroup Database
- */
-class LoadMonitorMySQL implements LoadMonitor {
- /** @var LoadBalancer */
- public $parent;
- /** @var BagOStuff */
- protected $srvCache;
- /** @var BagOStuff */
- protected $mainCache;
-
- public function __construct( $parent ) {
- $this->parent = $parent;
-
- $this->srvCache = ObjectCache::newAccelerator( 'hash' );
- $this->mainCache = wfGetMainCache();
- }
-
- public function scaleLoads( &$loads, $group = false, $wiki = false ) {
- }
-
- public function getLagTimes( $serverIndexes, $wiki ) {
- if ( count( $serverIndexes ) == 1 && reset( $serverIndexes ) == 0 ) {
- # Single server only, just return zero without caching
- return array( 0 => 0 );
- }
-
- $key = $this->getLagTimeCacheKey();
- # Randomize TTLs to reduce stampedes (4.0 - 5.0 sec)
- $ttl = mt_rand( 4e6, 5e6 ) / 1e6;
- # Keep keys around longer as fallbacks
- $staleTTL = 60;
-
- # (a) Check the local APC cache
- $value = $this->srvCache->get( $key );
- if ( $value && $value['timestamp'] > ( microtime( true ) - $ttl ) ) {
- wfDebugLog( 'replication', __FUNCTION__ . ": got lag times ($key) from local cache" );
- return $value['lagTimes']; // cache hit
- }
- $staleValue = $value ?: false;
-
- # (b) Check the shared cache and backfill APC
- $value = $this->mainCache->get( $key );
- if ( $value && $value['timestamp'] > ( microtime( true ) - $ttl ) ) {
- $this->srvCache->set( $key, $value, $staleTTL );
- wfDebugLog( 'replication', __FUNCTION__ . ": got lag times ($key) from main cache" );
-
- return $value['lagTimes']; // cache hit
- }
- $staleValue = $value ?: $staleValue;
-
- # (c) Cache key missing or expired; regenerate and backfill
- if ( $this->mainCache->lock( $key, 0, 10 ) ) {
- # Let this process alone update the cache value
- $cache = $this->mainCache;
- /** @noinspection PhpUnusedLocalVariableInspection */
- $unlocker = new ScopedCallback( function () use ( $cache, $key ) {
- $cache->unlock( $key );
- } );
- } elseif ( $staleValue ) {
- # Could not acquire lock but an old cache exists, so use it
- return $staleValue['lagTimes'];
- }
-
- $lagTimes = array();
- foreach ( $serverIndexes as $i ) {
- if ( $i == 0 ) { # Master
- $lagTimes[$i] = 0;
- } elseif ( false !== ( $conn = $this->parent->getAnyOpenConnection( $i ) ) ) {
- $lagTimes[$i] = $conn->getLag();
- } elseif ( false !== ( $conn = $this->parent->openConnection( $i, $wiki ) ) ) {
- $lagTimes[$i] = $conn->getLag();
- # Close the connection to avoid sleeper connections piling up.
- # Note that the caller will pick one of these DBs and reconnect,
- # which is slightly inefficient, but this only matters for the lag
- # time cache miss cache, which is far less common that cache hits.
- $this->parent->closeConnection( $conn );
- }
- }
-
- # Add a timestamp key so we know when it was cached
- $value = array( 'lagTimes' => $lagTimes, 'timestamp' => microtime( true ) );
- $this->mainCache->set( $key, $value, $staleTTL );
- $this->srvCache->set( $key, $value, $staleTTL );
- wfDebugLog( 'replication', __FUNCTION__ . ": re-calculated lag times ($key)" );
-
- return $value['lagTimes'];
- }
-
- public function clearCaches() {
- $key = $this->getLagTimeCacheKey();
- $this->srvCache->delete( $key );
- $this->mainCache->delete( $key );
- }
-
- private function getLagTimeCacheKey() {
- # Lag is per-server, not per-DB, so key on the master DB name
- return wfGlobalCacheKey( 'lag-times', $this->parent->getServerName( 0 ) );
- }
-}
--- /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
+ */
+
+/**
+ * An interface for generating database load balancers
+ * @ingroup Database
+ */
+abstract class LBFactory {
+ /** @var LBFactory */
+ private static $instance;
+
+ /**
+ * Disables all access to the load balancer, will cause all database access
+ * to throw a DBAccessError
+ */
+ public static function disableBackend() {
+ global $wgLBFactoryConf;
+ self::$instance = new LBFactoryFake( $wgLBFactoryConf );
+ }
+
+ /**
+ * Get an LBFactory instance
+ *
+ * @return LBFactory
+ */
+ public static function singleton() {
+ global $wgLBFactoryConf;
+
+ if ( is_null( self::$instance ) ) {
+ $class = self::getLBFactoryClass( $wgLBFactoryConf );
+
+ self::$instance = new $class( $wgLBFactoryConf );
+ }
+
+ return self::$instance;
+ }
+
+ /**
+ * Returns the LBFactory class to use and the load balancer configuration.
+ *
+ * @param array $config (e.g. $wgLBFactoryConf)
+ * @return string Class name
+ */
+ public static function getLBFactoryClass( array $config ) {
+ // For configuration backward compatibility after removing
+ // underscores from class names in MediaWiki 1.23.
+ $bcClasses = array(
+ 'LBFactory_Simple' => 'LBFactorySimple',
+ 'LBFactory_Single' => 'LBFactorySingle',
+ 'LBFactory_Multi' => 'LBFactoryMulti',
+ 'LBFactory_Fake' => 'LBFactoryFake',
+ );
+
+ $class = $config['class'];
+
+ if ( isset( $bcClasses[$class] ) ) {
+ $class = $bcClasses[$class];
+ wfDeprecated(
+ '$wgLBFactoryConf must be updated. See RELEASE-NOTES for details',
+ '1.23'
+ );
+ }
+
+ return $class;
+ }
+
+ /**
+ * Shut down, close connections and destroy the cached instance.
+ */
+ public static function destroyInstance() {
+ if ( self::$instance ) {
+ self::$instance->shutdown();
+ self::$instance->forEachLBCallMethod( 'closeAll' );
+ self::$instance = null;
+ }
+ }
+
+ /**
+ * Set the instance to be the given object
+ *
+ * @param LBFactory $instance
+ */
+ public static function setInstance( $instance ) {
+ self::destroyInstance();
+ self::$instance = $instance;
+ }
+
+ /**
+ * Construct a factory based on a configuration array (typically from $wgLBFactoryConf)
+ * @param array $conf
+ */
+ abstract public function __construct( array $conf );
+
+ /**
+ * Create a new load balancer object. The resulting object will be untracked,
+ * not chronology-protected, and the caller is responsible for cleaning it up.
+ *
+ * @param bool|string $wiki Wiki ID, or false for the current wiki
+ * @return LoadBalancer
+ */
+ abstract public function newMainLB( $wiki = false );
+
+ /**
+ * Get a cached (tracked) load balancer object.
+ *
+ * @param bool|string $wiki Wiki ID, or false for the current wiki
+ * @return LoadBalancer
+ */
+ abstract public function getMainLB( $wiki = false );
+
+ /**
+ * Create a new load balancer for external storage. The resulting object will be
+ * untracked, not chronology-protected, and the caller is responsible for
+ * cleaning it up.
+ *
+ * @param string $cluster External storage cluster, or false for core
+ * @param bool|string $wiki Wiki ID, or false for the current wiki
+ * @return LoadBalancer
+ */
+ abstract protected function newExternalLB( $cluster, $wiki = false );
+
+ /**
+ * Get a cached (tracked) load balancer for external storage
+ *
+ * @param string $cluster External storage cluster, or false for core
+ * @param bool|string $wiki Wiki ID, or false for the current wiki
+ * @return LoadBalancer
+ */
+ abstract public function &getExternalLB( $cluster, $wiki = false );
+
+ /**
+ * Execute a function for each tracked load balancer
+ * The callback is called with the load balancer as the first parameter,
+ * and $params passed as the subsequent parameters.
+ *
+ * @param callable $callback
+ * @param array $params
+ */
+ abstract public function forEachLB( $callback, array $params = array() );
+
+ /**
+ * Prepare all tracked load balancers for shutdown
+ * STUB
+ */
+ public function shutdown() {
+ }
+
+ /**
+ * Call a method of each tracked load balancer
+ *
+ * @param string $methodName
+ * @param array $args
+ */
+ private function forEachLBCallMethod( $methodName, array $args = array() ) {
+ $this->forEachLB( function ( LoadBalancer $loadBalancer, $methodName, array $args ) {
+ call_user_func_array( array( $loadBalancer, $methodName ), $args );
+ }, array( $methodName, $args ) );
+ }
+
+ /**
+ * Commit on all connections. Done for two reasons:
+ * 1. To commit changes to the masters.
+ * 2. To release the snapshot on all connections, master and slave.
+ */
+ public function commitAll() {
+ $this->forEachLBCallMethod( 'commitAll' );
+ }
+
+ /**
+ * Commit changes on all master connections
+ */
+ public function commitMasterChanges() {
+ $this->forEachLBCallMethod( 'commitMasterChanges' );
+ }
+
+ /**
+ * Rollback changes on all master connections
+ * @since 1.23
+ */
+ public function rollbackMasterChanges() {
+ $this->forEachLBCallMethod( 'rollbackMasterChanges' );
+ }
+
+ /**
+ * Detemine if any master connection has pending changes.
+ * @since 1.23
+ * @return bool
+ */
+ public function hasMasterChanges() {
+ $ret = false;
+ $this->forEachLB( function ( LoadBalancer $lb ) use ( &$ret ) {
+ $ret = $ret || $lb->hasMasterChanges();
+ } );
+ return $ret;
+ }
+}
+
+/**
+ * Exception class for attempted DB access
+ */
+class DBAccessError extends MWException {
+ public function __construct() {
+ parent::__construct( "Mediawiki tried to access the database via wfGetDB(). " .
+ "This is not allowed." );
+ }
+}
--- /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
+ */
+
+/**
+ * LBFactory class that throws an error on any attempt to use it.
+ * This will typically be done via wfGetDB().
+ * Call LBFactory::disableBackend() to start using this, and
+ * LBFactory::enableBackend() to return to normal behavior
+ */
+class LBFactoryFake extends LBFactory {
+ public function __construct( array $conf ) {
+ }
+
+ public function newMainLB( $wiki = false ) {
+ throw new DBAccessError;
+ }
+
+ public function getMainLB( $wiki = false ) {
+ throw new DBAccessError;
+ }
+
+ protected function newExternalLB( $cluster, $wiki = false ) {
+ throw new DBAccessError;
+ }
+
+ public function &getExternalLB( $cluster, $wiki = false ) {
+ throw new DBAccessError;
+ }
+
+ public function forEachLB( $callback, array $params = array() ) {
+ }
+}
--- /dev/null
+<?php
+/**
+ * Advanced generator of database load balancing objects for wiki farms.
+ *
+ * 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
+ */
+
+/**
+ * A multi-wiki, multi-master factory for Wikimedia and similar installations.
+ * Ignores the old configuration globals
+ *
+ * Configuration:
+ * sectionsByDB A map of database names to section names.
+ *
+ * sectionLoads A 2-d map. For each section, gives a map of server names to
+ * load ratios. For example:
+ * array(
+ * 'section1' => array(
+ * 'db1' => 100,
+ * 'db2' => 100
+ * )
+ * )
+ *
+ * serverTemplate A server info associative array as documented for $wgDBservers.
+ * The host, hostName and load entries will be overridden.
+ *
+ * groupLoadsBySection A 3-d map giving server load ratios for each section and group.
+ * For example:
+ * array(
+ * 'section1' => array(
+ * 'group1' => array(
+ * 'db1' => 100,
+ * 'db2' => 100
+ * )
+ * )
+ * )
+ *
+ * groupLoadsByDB A 3-d map giving server load ratios by DB name.
+ *
+ * hostsByName A map of hostname to IP address.
+ *
+ * externalLoads A map of external storage cluster name to server load map.
+ *
+ * externalTemplateOverrides A set of server info keys overriding serverTemplate for external
+ * storage.
+ *
+ * templateOverridesByServer A 2-d map overriding serverTemplate and
+ * externalTemplateOverrides on a server-by-server basis. Applies
+ * to both core and external storage.
+ *
+ * templateOverridesByCluster A 2-d map overriding the server info by external storage cluster.
+ *
+ * masterTemplateOverrides An override array for all master servers.
+ *
+ * readOnlyBySection A map of section name to read-only message.
+ * Missing or false for read/write.
+ *
+ * @ingroup Database
+ */
+class LBFactoryMulti extends LBFactory {
+ // Required settings
+
+ /** @var array A map of database names to section names */
+ private $sectionsByDB;
+
+ /**
+ * @var array A 2-d map. For each section, gives a map of server names to
+ * load ratios
+ */
+ private $sectionLoads;
+
+ /**
+ * @var array A server info associative array as documented for
+ * $wgDBservers. The host, hostName and load entries will be
+ * overridden
+ */
+ private $serverTemplate;
+
+ // Optional settings
+
+ /** @var array A 3-d map giving server load ratios for each section and group */
+ private $groupLoadsBySection = array();
+
+ /** @var array A 3-d map giving server load ratios by DB name */
+ private $groupLoadsByDB = array();
+
+ /** @var array A map of hostname to IP address */
+ private $hostsByName = array();
+
+ /** @var array A map of external storage cluster name to server load map */
+ private $externalLoads = array();
+
+ /**
+ * @var array A set of server info keys overriding serverTemplate for
+ * external storage
+ */
+ private $externalTemplateOverrides;
+
+ /**
+ * @var array A 2-d map overriding serverTemplate and
+ * externalTemplateOverrides on a server-by-server basis. Applies to both
+ * core and external storage
+ */
+ private $templateOverridesByServer;
+
+ /** @var array A 2-d map overriding the server info by external storage cluster */
+ private $templateOverridesByCluster;
+
+ /** @var array An override array for all master servers */
+ private $masterTemplateOverrides;
+
+ /**
+ * @var array|bool A map of section name to read-only message. Missing or
+ * false for read/write
+ */
+ private $readOnlyBySection = array();
+
+ // Other stuff
+
+ /** @var array Load balancer factory configuration */
+ private $conf;
+
+ /** @var LoadBalancer[] */
+ private $mainLBs = array();
+
+ /** @var LoadBalancer[] */
+ private $extLBs = array();
+
+ /** @var string */
+ private $lastWiki;
+
+ /** @var string */
+ private $lastSection;
+
+ /**
+ * @param array $conf
+ * @throws MWException
+ */
+ public function __construct( array $conf ) {
+ $this->chronProt = new ChronologyProtector;
+ $this->conf = $conf;
+ $required = array( 'sectionsByDB', 'sectionLoads', 'serverTemplate' );
+ $optional = array( 'groupLoadsBySection', 'groupLoadsByDB', 'hostsByName',
+ 'externalLoads', 'externalTemplateOverrides', 'templateOverridesByServer',
+ 'templateOverridesByCluster', 'masterTemplateOverrides',
+ 'readOnlyBySection' );
+
+ foreach ( $required as $key ) {
+ if ( !isset( $conf[$key] ) ) {
+ throw new MWException( __CLASS__ . ": $key is required in configuration" );
+ }
+ $this->$key = $conf[$key];
+ }
+
+ foreach ( $optional as $key ) {
+ if ( isset( $conf[$key] ) ) {
+ $this->$key = $conf[$key];
+ }
+ }
+
+ // Check for read-only mode
+ $section = $this->getSectionForWiki();
+ if ( !empty( $this->readOnlyBySection[$section] ) ) {
+ global $wgReadOnly;
+ $wgReadOnly = $this->readOnlyBySection[$section];
+ }
+ }
+
+ /**
+ * @param bool|string $wiki
+ * @return string
+ */
+ private function getSectionForWiki( $wiki = false ) {
+ if ( $this->lastWiki === $wiki ) {
+ return $this->lastSection;
+ }
+ list( $dbName, ) = $this->getDBNameAndPrefix( $wiki );
+ if ( isset( $this->sectionsByDB[$dbName] ) ) {
+ $section = $this->sectionsByDB[$dbName];
+ } else {
+ $section = 'DEFAULT';
+ }
+ $this->lastSection = $section;
+ $this->lastWiki = $wiki;
+
+ return $section;
+ }
+
+ /**
+ * @param bool|string $wiki
+ * @return LoadBalancer
+ */
+ public function newMainLB( $wiki = false ) {
+ list( $dbName, ) = $this->getDBNameAndPrefix( $wiki );
+ $section = $this->getSectionForWiki( $wiki );
+ $groupLoads = array();
+ if ( isset( $this->groupLoadsByDB[$dbName] ) ) {
+ $groupLoads = $this->groupLoadsByDB[$dbName];
+ }
+
+ if ( isset( $this->groupLoadsBySection[$section] ) ) {
+ $groupLoads = array_merge_recursive( $groupLoads, $this->groupLoadsBySection[$section] );
+ }
+
+ return $this->newLoadBalancer(
+ $this->serverTemplate,
+ $this->sectionLoads[$section],
+ $groupLoads
+ );
+ }
+
+ /**
+ * @param bool|string $wiki
+ * @return LoadBalancer
+ */
+ public function getMainLB( $wiki = false ) {
+ $section = $this->getSectionForWiki( $wiki );
+ if ( !isset( $this->mainLBs[$section] ) ) {
+ $lb = $this->newMainLB( $wiki );
+ $lb->parentInfo( array( 'id' => "main-$section" ) );
+ $this->chronProt->initLB( $lb );
+ $this->mainLBs[$section] = $lb;
+ }
+
+ return $this->mainLBs[$section];
+ }
+
+ /**
+ * @param string $cluster
+ * @param bool|string $wiki
+ * @throws MWException
+ * @return LoadBalancer
+ */
+ protected function newExternalLB( $cluster, $wiki = false ) {
+ if ( !isset( $this->externalLoads[$cluster] ) ) {
+ throw new MWException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
+ }
+ $template = $this->serverTemplate;
+ if ( isset( $this->externalTemplateOverrides ) ) {
+ $template = $this->externalTemplateOverrides + $template;
+ }
+ if ( isset( $this->templateOverridesByCluster[$cluster] ) ) {
+ $template = $this->templateOverridesByCluster[$cluster] + $template;
+ }
+
+ return $this->newLoadBalancer( $template, $this->externalLoads[$cluster], array() );
+ }
+
+ /**
+ * @param string $cluster External storage cluster, or false for core
+ * @param bool|string $wiki Wiki ID, or false for the current wiki
+ * @return LoadBalancer
+ */
+ public function &getExternalLB( $cluster, $wiki = false ) {
+ if ( !isset( $this->extLBs[$cluster] ) ) {
+ $this->extLBs[$cluster] = $this->newExternalLB( $cluster, $wiki );
+ $this->extLBs[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
+ $this->chronProt->initLB( $this->extLBs[$cluster] );
+ }
+
+ return $this->extLBs[$cluster];
+ }
+
+ /**
+ * Make a new load balancer object based on template and load array
+ *
+ * @param array $template
+ * @param array $loads
+ * @param array $groupLoads
+ * @return LoadBalancer
+ */
+ private function newLoadBalancer( $template, $loads, $groupLoads ) {
+ $servers = $this->makeServerArray( $template, $loads, $groupLoads );
+ $lb = new LoadBalancer( array(
+ 'servers' => $servers,
+ ) );
+
+ return $lb;
+ }
+
+ /**
+ * Make a server array as expected by LoadBalancer::__construct, using a template and load array
+ *
+ * @param array $template
+ * @param array $loads
+ * @param array $groupLoads
+ * @return array
+ */
+ private function makeServerArray( $template, $loads, $groupLoads ) {
+ $servers = array();
+ $master = true;
+ $groupLoadsByServer = $this->reindexGroupLoads( $groupLoads );
+ foreach ( $groupLoadsByServer as $server => $stuff ) {
+ if ( !isset( $loads[$server] ) ) {
+ $loads[$server] = 0;
+ }
+ }
+ foreach ( $loads as $serverName => $load ) {
+ $serverInfo = $template;
+ if ( $master ) {
+ $serverInfo['master'] = true;
+ if ( isset( $this->masterTemplateOverrides ) ) {
+ $serverInfo = $this->masterTemplateOverrides + $serverInfo;
+ }
+ $master = false;
+ }
+ if ( isset( $this->templateOverridesByServer[$serverName] ) ) {
+ $serverInfo = $this->templateOverridesByServer[$serverName] + $serverInfo;
+ }
+ if ( isset( $groupLoadsByServer[$serverName] ) ) {
+ $serverInfo['groupLoads'] = $groupLoadsByServer[$serverName];
+ }
+ if ( isset( $this->hostsByName[$serverName] ) ) {
+ $serverInfo['host'] = $this->hostsByName[$serverName];
+ } else {
+ $serverInfo['host'] = $serverName;
+ }
+ $serverInfo['hostName'] = $serverName;
+ $serverInfo['load'] = $load;
+ $servers[] = $serverInfo;
+ }
+
+ return $servers;
+ }
+
+ /**
+ * Take a group load array indexed by group then server, and reindex it by server then group
+ * @param array $groupLoads
+ * @return array
+ */
+ private function reindexGroupLoads( $groupLoads ) {
+ $reindexed = array();
+ foreach ( $groupLoads as $group => $loads ) {
+ foreach ( $loads as $server => $load ) {
+ $reindexed[$server][$group] = $load;
+ }
+ }
+
+ return $reindexed;
+ }
+
+ /**
+ * Get the database name and prefix based on the wiki ID
+ * @param bool|string $wiki
+ * @return array
+ */
+ private function getDBNameAndPrefix( $wiki = false ) {
+ if ( $wiki === false ) {
+ global $wgDBname, $wgDBprefix;
+
+ return array( $wgDBname, $wgDBprefix );
+ } else {
+ return wfSplitWikiID( $wiki );
+ }
+ }
+
+ /**
+ * Execute a function for each tracked load balancer
+ * The callback is called with the load balancer as the first parameter,
+ * and $params passed as the subsequent parameters.
+ * @param callable $callback
+ * @param array $params
+ */
+ public function forEachLB( $callback, array $params = array() ) {
+ foreach ( $this->mainLBs as $lb ) {
+ call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
+ }
+ foreach ( $this->extLBs as $lb ) {
+ call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
+ }
+ }
+
+ public function shutdown() {
+ foreach ( $this->mainLBs as $lb ) {
+ $this->chronProt->shutdownLB( $lb );
+ }
+ foreach ( $this->extLBs as $extLB ) {
+ $this->chronProt->shutdownLB( $extLB );
+ }
+ $this->chronProt->shutdown();
+ $this->commitMasterChanges();
+ }
+}
--- /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
+ */
+
+/**
+ * A simple single-master LBFactory that gets its configuration from the b/c globals
+ */
+class LBFactorySimple extends LBFactory {
+ /** @var LoadBalancer */
+ private $mainLB;
+
+ /** @var LoadBalancer[] */
+ private $extLBs = array();
+
+ /** @var ChronologyProtector */
+ private $chronProt;
+
+ public function __construct( array $conf ) {
+ $this->chronProt = new ChronologyProtector;
+ }
+
+ /**
+ * @param bool|string $wiki
+ * @return LoadBalancer
+ */
+ public function newMainLB( $wiki = false ) {
+ global $wgDBservers;
+ if ( $wgDBservers ) {
+ $servers = $wgDBservers;
+ } else {
+ global $wgDBserver, $wgDBuser, $wgDBpassword, $wgDBname, $wgDBtype, $wgDebugDumpSql;
+ global $wgDBssl, $wgDBcompress;
+
+ $flags = DBO_DEFAULT;
+ if ( $wgDebugDumpSql ) {
+ $flags |= DBO_DEBUG;
+ }
+ if ( $wgDBssl ) {
+ $flags |= DBO_SSL;
+ }
+ if ( $wgDBcompress ) {
+ $flags |= DBO_COMPRESS;
+ }
+
+ $servers = array( array(
+ 'host' => $wgDBserver,
+ 'user' => $wgDBuser,
+ 'password' => $wgDBpassword,
+ 'dbname' => $wgDBname,
+ 'type' => $wgDBtype,
+ 'load' => 1,
+ 'flags' => $flags
+ ) );
+ }
+
+ return new LoadBalancer( array(
+ 'servers' => $servers,
+ ) );
+ }
+
+ /**
+ * @param bool|string $wiki
+ * @return LoadBalancer
+ */
+ public function getMainLB( $wiki = false ) {
+ if ( !isset( $this->mainLB ) ) {
+ $this->mainLB = $this->newMainLB( $wiki );
+ $this->mainLB->parentInfo( array( 'id' => 'main' ) );
+ $this->chronProt->initLB( $this->mainLB );
+ }
+
+ return $this->mainLB;
+ }
+
+ /**
+ * @throws MWException
+ * @param string $cluster
+ * @param bool|string $wiki
+ * @return LoadBalancer
+ */
+ protected function newExternalLB( $cluster, $wiki = false ) {
+ global $wgExternalServers;
+ if ( !isset( $wgExternalServers[$cluster] ) ) {
+ throw new MWException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
+ }
+
+ return new LoadBalancer( array(
+ 'servers' => $wgExternalServers[$cluster]
+ ) );
+ }
+
+ /**
+ * @param string $cluster
+ * @param bool|string $wiki
+ * @return array
+ */
+ public function &getExternalLB( $cluster, $wiki = false ) {
+ if ( !isset( $this->extLBs[$cluster] ) ) {
+ $this->extLBs[$cluster] = $this->newExternalLB( $cluster, $wiki );
+ $this->extLBs[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
+ $this->chronProt->initLB( $this->extLBs[$cluster] );
+ }
+
+ return $this->extLBs[$cluster];
+ }
+
+ /**
+ * Execute a function for each tracked load balancer
+ * The callback is called with the load balancer as the first parameter,
+ * and $params passed as the subsequent parameters.
+ *
+ * @param callable $callback
+ * @param array $params
+ */
+ public function forEachLB( $callback, array $params = array() ) {
+ if ( isset( $this->mainLB ) ) {
+ call_user_func_array( $callback, array_merge( array( $this->mainLB ), $params ) );
+ }
+ foreach ( $this->extLBs as $lb ) {
+ call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
+ }
+ }
+
+ public function shutdown() {
+ if ( $this->mainLB ) {
+ $this->chronProt->shutdownLB( $this->mainLB );
+ }
+ foreach ( $this->extLBs as $extLB ) {
+ $this->chronProt->shutdownLB( $extLB );
+ }
+ $this->chronProt->shutdown();
+ $this->commitMasterChanges();
+ }
+}
--- /dev/null
+<?php
+/**
+ * Simple generator of database connections that always returns the same object.
+ *
+ * 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
+ */
+
+/**
+ * An LBFactory class that always returns a single database object.
+ */
+class LBFactorySingle extends LBFactory {
+ /** @var LoadBalancerSingle */
+ private $lb;
+
+ /**
+ * @param array $conf An associative array with one member:
+ * - connection: The DatabaseBase connection object
+ */
+ public function __construct( array $conf ) {
+ $this->lb = new LoadBalancerSingle( $conf );
+ }
+
+ /**
+ * @param bool|string $wiki
+ * @return LoadBalancerSingle
+ */
+ public function newMainLB( $wiki = false ) {
+ return $this->lb;
+ }
+
+ /**
+ * @param bool|string $wiki
+ * @return LoadBalancerSingle
+ */
+ public function getMainLB( $wiki = false ) {
+ return $this->lb;
+ }
+
+ /**
+ * @param string $cluster External storage cluster, or false for core
+ * @param bool|string $wiki Wiki ID, or false for the current wiki
+ * @return LoadBalancerSingle
+ */
+ protected function newExternalLB( $cluster, $wiki = false ) {
+ return $this->lb;
+ }
+
+ /**
+ * @param string $cluster External storage cluster, or false for core
+ * @param bool|string $wiki Wiki ID, or false for the current wiki
+ * @return LoadBalancerSingle
+ */
+ public function &getExternalLB( $cluster, $wiki = false ) {
+ return $this->lb;
+ }
+
+ /**
+ * @param string|callable $callback
+ * @param array $params
+ */
+ public function forEachLB( $callback, array $params = array() ) {
+ call_user_func_array( $callback, array_merge( array( $this->lb ), $params ) );
+ }
+}
+
+/**
+ * Helper class for LBFactorySingle.
+ */
+class LoadBalancerSingle extends LoadBalancer {
+ /** @var DatabaseBase */
+ private $db;
+
+ /**
+ * @param array $params
+ */
+ public function __construct( array $params ) {
+ $this->db = $params['connection'];
+ parent::__construct( array( 'servers' => array( array(
+ 'type' => $this->db->getType(),
+ 'host' => $this->db->getServer(),
+ 'dbname' => $this->db->getDBname(),
+ 'load' => 1,
+ ) ) ) );
+ }
+
+ /**
+ *
+ * @param string $server
+ * @param bool $dbNameOverride
+ *
+ * @return DatabaseBase
+ */
+ protected function reallyOpenConnection( $server, $dbNameOverride = false ) {
+ return $this->db;
+ }
+}
--- /dev/null
+<?php
+/**
+ * Database load balancing.
+ *
+ * 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 load balancing object
+ *
+ * @todo document
+ * @ingroup Database
+ */
+class LoadBalancer {
+ /** @var array[] Map of (server index => server config array) */
+ private $mServers;
+ /** @var array[] Map of (local/foreignUsed/foreignFree => server index => DatabaseBase array) */
+ private $mConns;
+ /** @var array Map of (server index => weight) */
+ private $mLoads;
+ /** @var array[] Map of (group => server index => weight) */
+ private $mGroupLoads;
+ /** @var bool Whether to disregard slave lag as a factor in slave selection */
+ private $mAllowLagged;
+ /** @var integer Seconds to spend waiting on slave lag to resolve */
+ private $mWaitTimeout;
+
+ /** @var array LBFactory information */
+ private $mParentInfo;
+ /** @var string The LoadMonitor subclass name */
+ private $mLoadMonitorClass;
+ /** @var LoadMonitor */
+ private $mLoadMonitor;
+
+ /** @var bool|DatabaseBase Database connection that caused a problem */
+ private $mErrorConnection;
+ /** @var integer The generic (not query grouped) slave index (of $mServers) */
+ private $mReadIndex;
+ /** @var bool|DBMasterPos False if not set */
+ private $mWaitForPos;
+ /** @var bool Whether the generic reader fell back to a lagged slave */
+ private $mLaggedSlaveMode;
+ /** @var string The last DB selection or connection error */
+ private $mLastError = 'Unknown error';
+ /** @var integer Total connections opened */
+ private $connsOpened = 0;
+
+ /** @var integer Warn when this many connection are held */
+ const CONN_HELD_WARN_THRESHOLD = 10;
+
+ /**
+ * @param array $params Array with keys:
+ * servers Required. Array of server info structures.
+ * loadMonitor Name of a class used to fetch server lag and load.
+ * @throws MWException
+ */
+ public function __construct( array $params ) {
+ if ( !isset( $params['servers'] ) ) {
+ throw new MWException( __CLASS__ . ': missing servers parameter' );
+ }
+ $this->mServers = $params['servers'];
+ $this->mWaitTimeout = 10;
+
+ $this->mReadIndex = -1;
+ $this->mWriteIndex = -1;
+ $this->mConns = array(
+ 'local' => array(),
+ 'foreignUsed' => array(),
+ 'foreignFree' => array() );
+ $this->mLoads = array();
+ $this->mWaitForPos = false;
+ $this->mLaggedSlaveMode = false;
+ $this->mErrorConnection = false;
+ $this->mAllowLagged = false;
+
+ if ( isset( $params['loadMonitor'] ) ) {
+ $this->mLoadMonitorClass = $params['loadMonitor'];
+ } else {
+ $master = reset( $params['servers'] );
+ if ( isset( $master['type'] ) && $master['type'] === 'mysql' ) {
+ $this->mLoadMonitorClass = 'LoadMonitorMySQL';
+ } else {
+ $this->mLoadMonitorClass = 'LoadMonitorNull';
+ }
+ }
+
+ foreach ( $params['servers'] as $i => $server ) {
+ $this->mLoads[$i] = $server['load'];
+ if ( isset( $server['groupLoads'] ) ) {
+ foreach ( $server['groupLoads'] as $group => $ratio ) {
+ if ( !isset( $this->mGroupLoads[$group] ) ) {
+ $this->mGroupLoads[$group] = array();
+ }
+ $this->mGroupLoads[$group][$i] = $ratio;
+ }
+ }
+ }
+ }
+
+ /**
+ * Get a LoadMonitor instance
+ *
+ * @return LoadMonitor
+ */
+ private function getLoadMonitor() {
+ if ( !isset( $this->mLoadMonitor ) ) {
+ $class = $this->mLoadMonitorClass;
+ $this->mLoadMonitor = new $class( $this );
+ }
+
+ return $this->mLoadMonitor;
+ }
+
+ /**
+ * Get or set arbitrary data used by the parent object, usually an LBFactory
+ * @param mixed $x
+ * @return mixed
+ */
+ public function parentInfo( $x = null ) {
+ return wfSetVar( $this->mParentInfo, $x );
+ }
+
+ /**
+ * Given an array of non-normalised probabilities, this function will select
+ * an element and return the appropriate key
+ *
+ * @deprecated since 1.21, use ArrayUtils::pickRandom()
+ *
+ * @param array $weights
+ * @return bool|int|string
+ */
+ public function pickRandom( array $weights ) {
+ return ArrayUtils::pickRandom( $weights );
+ }
+
+ /**
+ * @param array $loads
+ * @param bool|string $wiki Wiki to get non-lagged for
+ * @param float $maxLag Restrict the maximum allowed lag to this many seconds
+ * @return bool|int|string
+ */
+ private function getRandomNonLagged( array $loads, $wiki = false, $maxLag = INF ) {
+ $lags = $this->getLagTimes( $wiki );
+
+ # Unset excessively lagged servers
+ foreach ( $lags as $i => $lag ) {
+ if ( $i != 0 ) {
+ $maxServerLag = $maxLag;
+ if ( isset( $this->mServers[$i]['max lag'] ) ) {
+ $maxServerLag = min( $maxServerLag, $this->mServers[$i]['max lag'] );
+ }
+ if ( $lag === false ) {
+ wfDebugLog( 'replication', "Server #$i is not replicating" );
+ unset( $loads[$i] );
+ } elseif ( $lag > $maxServerLag ) {
+ wfDebugLog( 'replication', "Server #$i is excessively lagged ($lag seconds)" );
+ unset( $loads[$i] );
+ }
+ }
+ }
+
+ # Find out if all the slaves with non-zero load are lagged
+ $sum = 0;
+ foreach ( $loads as $load ) {
+ $sum += $load;
+ }
+ if ( $sum == 0 ) {
+ # No appropriate DB servers except maybe the master and some slaves with zero load
+ # Do NOT use the master
+ # Instead, this function will return false, triggering read-only mode,
+ # and a lagged slave will be used instead.
+ return false;
+ }
+
+ if ( count( $loads ) == 0 ) {
+ return false;
+ }
+
+ #wfDebugLog( 'connect', var_export( $loads, true ) );
+
+ # Return a random representative of the remainder
+ return ArrayUtils::pickRandom( $loads );
+ }
+
+ /**
+ * Get the index of the reader connection, which may be a slave
+ * This takes into account load ratios and lag times. It should
+ * always return a consistent index during a given invocation
+ *
+ * Side effect: opens connections to databases
+ * @param string|bool $group Query group, or false for the generic reader
+ * @param string|bool $wiki Wiki ID, or false for the current wiki
+ * @throws MWException
+ * @return bool|int|string
+ */
+ public function getReaderIndex( $group = false, $wiki = false ) {
+ global $wgDBtype;
+
+ # @todo FIXME: For now, only go through all this for mysql databases
+ if ( $wgDBtype != 'mysql' ) {
+ return $this->getWriterIndex();
+ }
+
+ if ( count( $this->mServers ) == 1 ) {
+ # Skip the load balancing if there's only one server
+ return 0;
+ } elseif ( $group === false && $this->mReadIndex >= 0 ) {
+ # Shortcut if generic reader exists already
+ return $this->mReadIndex;
+ }
+
+ # Find the relevant load array
+ if ( $group !== false ) {
+ if ( isset( $this->mGroupLoads[$group] ) ) {
+ $nonErrorLoads = $this->mGroupLoads[$group];
+ } else {
+ # No loads for this group, return false and the caller can use some other group
+ wfDebug( __METHOD__ . ": no loads for group $group\n" );
+
+ return false;
+ }
+ } else {
+ $nonErrorLoads = $this->mLoads;
+ }
+
+ if ( !count( $nonErrorLoads ) ) {
+ throw new MWException( "Empty server array given to LoadBalancer" );
+ }
+
+ # Scale the configured load ratios according to the dynamic load (if the load monitor supports it)
+ $this->getLoadMonitor()->scaleLoads( $nonErrorLoads, $group, $wiki );
+
+ $laggedSlaveMode = false;
+
+ # No server found yet
+ $i = false;
+ # First try quickly looking through the available servers for a server that
+ # meets our criteria
+ $currentLoads = $nonErrorLoads;
+ while ( count( $currentLoads ) ) {
+ if ( $this->mAllowLagged || $laggedSlaveMode ) {
+ $i = ArrayUtils::pickRandom( $currentLoads );
+ } else {
+ $i = false;
+ if ( $this->mWaitForPos && $this->mWaitForPos->asOfTime() ) {
+ # ChronologyProtecter causes mWaitForPos to be set via sessions.
+ # This triggers doWait() after connect, so it's especially good to
+ # avoid lagged servers so as to avoid just blocking in that method.
+ $ago = microtime( true ) - $this->mWaitForPos->asOfTime();
+ # Aim for <= 1 second of waiting (being too picky can backfire)
+ $i = $this->getRandomNonLagged( $currentLoads, $wiki, $ago + 1 );
+ }
+ if ( $i === false ) {
+ # Any server with less lag than it's 'max lag' param is preferable
+ $i = $this->getRandomNonLagged( $currentLoads, $wiki );
+ }
+ if ( $i === false && count( $currentLoads ) != 0 ) {
+ # All slaves lagged. Switch to read-only mode
+ wfDebugLog( 'replication', "All slaves lagged. Switch to read-only mode" );
+ $i = ArrayUtils::pickRandom( $currentLoads );
+ $laggedSlaveMode = true;
+ }
+ }
+
+ if ( $i === false ) {
+ # pickRandom() returned false
+ # This is permanent and means the configuration or the load monitor
+ # wants us to return false.
+ wfDebugLog( 'connect', __METHOD__ . ": pickRandom() returned false" );
+
+ return false;
+ }
+
+ $serverName = $this->getServerName( $i );
+ wfDebugLog( 'connect', __METHOD__ . ": Using reader #$i: $serverName..." );
+
+ $conn = $this->openConnection( $i, $wiki );
+ if ( !$conn ) {
+ wfDebugLog( 'connect', __METHOD__ . ": Failed connecting to $i/$wiki" );
+ unset( $nonErrorLoads[$i] );
+ unset( $currentLoads[$i] );
+ $i = false;
+ continue;
+ }
+
+ // Decrement reference counter, we are finished with this connection.
+ // It will be incremented for the caller later.
+ if ( $wiki !== false ) {
+ $this->reuseConnection( $conn );
+ }
+
+ # Return this server
+ break;
+ }
+
+ # If all servers were down, quit now
+ if ( !count( $nonErrorLoads ) ) {
+ wfDebugLog( 'connect', "All servers down" );
+ }
+
+ if ( $i !== false ) {
+ # Slave connection successful
+ # Wait for the session master pos for a short time
+ if ( $this->mWaitForPos && $i > 0 ) {
+ if ( !$this->doWait( $i ) ) {
+ $this->mServers[$i]['slave pos'] = $conn->getSlavePos();
+ }
+ }
+ if ( $this->mReadIndex <= 0 && $this->mLoads[$i] > 0 && $group === false ) {
+ $this->mReadIndex = $i;
+ # Record if the generic reader index is in "lagged slave" mode
+ if ( $laggedSlaveMode ) {
+ $this->mLaggedSlaveMode = true;
+ }
+ }
+ $serverName = $this->getServerName( $i );
+ wfDebug( __METHOD__ . ": using server $serverName for group '$group'\n" );
+ }
+
+ return $i;
+ }
+
+ /**
+ * Set the master wait position
+ * If a DB_SLAVE connection has been opened already, waits
+ * Otherwise sets a variable telling it to wait if such a connection is opened
+ * @param DBMasterPos $pos
+ */
+ public function waitFor( $pos ) {
+ $this->mWaitForPos = $pos;
+ $i = $this->mReadIndex;
+
+ if ( $i > 0 ) {
+ if ( !$this->doWait( $i ) ) {
+ $this->mServers[$i]['slave pos'] = $this->getAnyOpenConnection( $i )->getSlavePos();
+ $this->mLaggedSlaveMode = true;
+ }
+ }
+ }
+
+ /**
+ * Set the master wait position and wait for a "generic" slave to catch up to it
+ *
+ * This can be used a faster proxy for waitForAll()
+ *
+ * @param DBMasterPos $pos
+ * @param int $timeout Max seconds to wait; default is mWaitTimeout
+ * @return bool Success (able to connect and no timeouts reached)
+ * @since 1.26
+ */
+ public function waitForOne( $pos, $timeout = null ) {
+ $this->mWaitForPos = $pos;
+
+ $i = $this->mReadIndex;
+ if ( $i <= 0 ) {
+ // Pick a generic slave if there isn't one yet
+ $readLoads = $this->mLoads;
+ unset( $readLoads[$this->getWriterIndex()] ); // slaves only
+ $readLoads = array_filter( $readLoads ); // with non-zero load
+ $i = ArrayUtils::pickRandom( $readLoads );
+ }
+
+ if ( $i > 0 ) {
+ $ok = $this->doWait( $i, true, $timeout );
+ } else {
+ $ok = true; // no applicable loads
+ }
+
+ return $ok;
+ }
+
+ /**
+ * Set the master wait position and wait for ALL slaves to catch up to it
+ * @param DBMasterPos $pos
+ * @param int $timeout Max seconds to wait; default is mWaitTimeout
+ * @return bool Success (able to connect and no timeouts reached)
+ */
+ public function waitForAll( $pos, $timeout = null ) {
+ $this->mWaitForPos = $pos;
+ $serverCount = count( $this->mServers );
+
+ $ok = true;
+ for ( $i = 1; $i < $serverCount; $i++ ) {
+ if ( $this->mLoads[$i] > 0 ) {
+ $ok = $this->doWait( $i, true, $timeout ) && $ok;
+ }
+ }
+
+ return $ok;
+ }
+
+ /**
+ * Get any open connection to a given server index, local or foreign
+ * Returns false if there is no connection open
+ *
+ * @param int $i
+ * @return DatabaseBase|bool False on failure
+ */
+ public function getAnyOpenConnection( $i ) {
+ foreach ( $this->mConns as $conns ) {
+ if ( !empty( $conns[$i] ) ) {
+ return reset( $conns[$i] );
+ }
+ }
+
+ return false;
+ }
+
+ /**
+ * Wait for a given slave to catch up to the master pos stored in $this
+ * @param int $index Server index
+ * @param bool $open Check the server even if a new connection has to be made
+ * @param int $timeout Max seconds to wait; default is mWaitTimeout
+ * @return bool
+ */
+ protected function doWait( $index, $open = false, $timeout = null ) {
+ $close = false; // close the connection afterwards
+
+ # Find a connection to wait on, creating one if needed and allowed
+ $conn = $this->getAnyOpenConnection( $index );
+ if ( !$conn ) {
+ if ( !$open ) {
+ wfDebug( __METHOD__ . ": no connection open\n" );
+
+ return false;
+ } else {
+ $conn = $this->openConnection( $index, '' );
+ if ( !$conn ) {
+ wfDebug( __METHOD__ . ": failed to open connection\n" );
+
+ return false;
+ }
+ // Avoid connection spam in waitForAll() when connections
+ // are made just for the sake of doing this lag check.
+ $close = true;
+ }
+ }
+
+ wfDebug( __METHOD__ . ": Waiting for slave #$index to catch up...\n" );
+ $timeout = $timeout ?: $this->mWaitTimeout;
+ $result = $conn->masterPosWait( $this->mWaitForPos, $timeout );
+
+ if ( $result == -1 || is_null( $result ) ) {
+ # Timed out waiting for slave, use master instead
+ $server = $server = $this->getServerName( $index );
+ $msg = __METHOD__ . ": Timed out waiting on $server pos {$this->mWaitForPos}";
+ wfDebug( "$msg\n" );
+ wfDebugLog( 'DBPerformance', "$msg:\n" . wfBacktrace( true ) );
+ $ok = false;
+ } else {
+ wfDebug( __METHOD__ . ": Done\n" );
+ $ok = true;
+ }
+
+ if ( $close ) {
+ $this->closeConnection( $conn );
+ }
+
+ return $ok;
+ }
+
+ /**
+ * Get a connection by index
+ * This is the main entry point for this class.
+ *
+ * @param int $i Server index
+ * @param array|string|bool $groups Query group(s), or false for the generic reader
+ * @param string|bool $wiki Wiki ID, or false for the current wiki
+ *
+ * @throws MWException
+ * @return DatabaseBase
+ */
+ public function getConnection( $i, $groups = array(), $wiki = false ) {
+ if ( $i === null || $i === false ) {
+ throw new MWException( 'Attempt to call ' . __METHOD__ .
+ ' with invalid server index' );
+ }
+
+ if ( $wiki === wfWikiID() ) {
+ $wiki = false;
+ }
+
+ $groups = ( $groups === false || $groups === array() )
+ ? array( false ) // check one "group": the generic pool
+ : (array)$groups;
+
+ $masterOnly = ( $i == DB_MASTER || $i == $this->getWriterIndex() );
+ $oldConnsOpened = $this->connsOpened; // connections open now
+
+ if ( $i == DB_MASTER ) {
+ $i = $this->getWriterIndex();
+ } else {
+ # Try to find an available server in any the query groups (in order)
+ foreach ( $groups as $group ) {
+ $groupIndex = $this->getReaderIndex( $group, $wiki );
+ if ( $groupIndex !== false ) {
+ $i = $groupIndex;
+ break;
+ }
+ }
+ }
+
+ # Operation-based index
+ if ( $i == DB_SLAVE ) {
+ $this->mLastError = 'Unknown error'; // reset error string
+ # Try the general server pool if $groups are unavailable.
+ $i = in_array( false, $groups, true )
+ ? false // don't bother with this if that is what was tried above
+ : $this->getReaderIndex( false, $wiki );
+ # Couldn't find a working server in getReaderIndex()?
+ if ( $i === false ) {
+ $this->mLastError = 'No working slave server: ' . $this->mLastError;
+
+ return $this->reportConnectionError();
+ }
+ }
+
+ # Now we have an explicit index into the servers array
+ $conn = $this->openConnection( $i, $wiki );
+ if ( !$conn ) {
+ return $this->reportConnectionError();
+ }
+
+ # Profile any new connections that happen
+ if ( $this->connsOpened > $oldConnsOpened ) {
+ $host = $conn->getServer();
+ $dbname = $conn->getDBname();
+ $trxProf = Profiler::instance()->getTransactionProfiler();
+ $trxProf->recordConnection( $host, $dbname, $masterOnly );
+ }
+
+ return $conn;
+ }
+
+ /**
+ * Mark a foreign connection as being available for reuse under a different
+ * DB name or prefix. This mechanism is reference-counted, and must be called
+ * the same number of times as getConnection() to work.
+ *
+ * @param DatabaseBase $conn
+ * @throws MWException
+ */
+ public function reuseConnection( $conn ) {
+ $serverIndex = $conn->getLBInfo( 'serverIndex' );
+ $refCount = $conn->getLBInfo( 'foreignPoolRefCount' );
+ if ( $serverIndex === null || $refCount === null ) {
+ wfDebug( __METHOD__ . ": this connection was not opened as a foreign connection\n" );
+
+ /**
+ * This can happen in code like:
+ * foreach ( $dbs as $db ) {
+ * $conn = $lb->getConnection( DB_SLAVE, array(), $db );
+ * ...
+ * $lb->reuseConnection( $conn );
+ * }
+ * When a connection to the local DB is opened in this way, reuseConnection()
+ * should be ignored
+ */
+
+ return;
+ }
+
+ $dbName = $conn->getDBname();
+ $prefix = $conn->tablePrefix();
+ if ( strval( $prefix ) !== '' ) {
+ $wiki = "$dbName-$prefix";
+ } else {
+ $wiki = $dbName;
+ }
+ if ( $this->mConns['foreignUsed'][$serverIndex][$wiki] !== $conn ) {
+ throw new MWException( __METHOD__ . ": connection not found, has " .
+ "the connection been freed already?" );
+ }
+ $conn->setLBInfo( 'foreignPoolRefCount', --$refCount );
+ if ( $refCount <= 0 ) {
+ $this->mConns['foreignFree'][$serverIndex][$wiki] = $conn;
+ unset( $this->mConns['foreignUsed'][$serverIndex][$wiki] );
+ wfDebug( __METHOD__ . ": freed connection $serverIndex/$wiki\n" );
+ } else {
+ wfDebug( __METHOD__ . ": reference count for $serverIndex/$wiki reduced to $refCount\n" );
+ }
+ }
+
+ /**
+ * Get a database connection handle reference
+ *
+ * The handle's methods wrap simply wrap those of a DatabaseBase handle
+ *
+ * @see LoadBalancer::getConnection() for parameter information
+ *
+ * @param int $db
+ * @param array|string|bool $groups Query group(s), or false for the generic reader
+ * @param string|bool $wiki Wiki ID, or false for the current wiki
+ * @return DBConnRef
+ */
+ public function getConnectionRef( $db, $groups = array(), $wiki = false ) {
+ return new DBConnRef( $this, $this->getConnection( $db, $groups, $wiki ) );
+ }
+
+ /**
+ * Get a database connection handle reference without connecting yet
+ *
+ * The handle's methods wrap simply wrap those of a DatabaseBase handle
+ *
+ * @see LoadBalancer::getConnection() for parameter information
+ *
+ * @param int $db
+ * @param array|string|bool $groups Query group(s), or false for the generic reader
+ * @param string|bool $wiki Wiki ID, or false for the current wiki
+ * @return DBConnRef
+ */
+ public function getLazyConnectionRef( $db, $groups = array(), $wiki = false ) {
+ return new DBConnRef( $this, array( $db, $groups, $wiki ) );
+ }
+
+ /**
+ * Open a connection to the server given by the specified index
+ * Index must be an actual index into the array.
+ * If the server is already open, returns it.
+ *
+ * On error, returns false, and the connection which caused the
+ * error will be available via $this->mErrorConnection.
+ *
+ * @param int $i Server index
+ * @param string|bool $wiki Wiki ID, or false for the current wiki
+ * @return DatabaseBase
+ *
+ * @access private
+ */
+ public function openConnection( $i, $wiki = false ) {
+ if ( $wiki !== false ) {
+ $conn = $this->openForeignConnection( $i, $wiki );
+ } elseif ( isset( $this->mConns['local'][$i][0] ) ) {
+ $conn = $this->mConns['local'][$i][0];
+ } else {
+ $server = $this->mServers[$i];
+ $server['serverIndex'] = $i;
+ $conn = $this->reallyOpenConnection( $server, false );
+ $serverName = $this->getServerName( $i );
+ if ( $conn->isOpen() ) {
+ wfDebug( "Connected to database $i at $serverName\n" );
+ $this->mConns['local'][$i][0] = $conn;
+ } else {
+ wfDebug( "Failed to connect to database $i at $serverName\n" );
+ $this->mErrorConnection = $conn;
+ $conn = false;
+ }
+ }
+
+ if ( $conn && !$conn->isOpen() ) {
+ // Connection was made but later unrecoverably lost for some reason.
+ // Do not return a handle that will just throw exceptions on use,
+ // but let the calling code (e.g. getReaderIndex) try another server.
+ // See DatabaseMyslBase::ping() for how this can happen.
+ $this->mErrorConnection = $conn;
+ $conn = false;
+ }
+
+ return $conn;
+ }
+
+ /**
+ * Open a connection to a foreign DB, or return one if it is already open.
+ *
+ * Increments a reference count on the returned connection which locks the
+ * connection to the requested wiki. This reference count can be
+ * decremented by calling reuseConnection().
+ *
+ * If a connection is open to the appropriate server already, but with the wrong
+ * database, it will be switched to the right database and returned, as long as
+ * it has been freed first with reuseConnection().
+ *
+ * On error, returns false, and the connection which caused the
+ * error will be available via $this->mErrorConnection.
+ *
+ * @param int $i Server index
+ * @param string $wiki Wiki ID to open
+ * @return DatabaseBase
+ */
+ private function openForeignConnection( $i, $wiki ) {
+ list( $dbName, $prefix ) = wfSplitWikiID( $wiki );
+ if ( isset( $this->mConns['foreignUsed'][$i][$wiki] ) ) {
+ // Reuse an already-used connection
+ $conn = $this->mConns['foreignUsed'][$i][$wiki];
+ wfDebug( __METHOD__ . ": reusing connection $i/$wiki\n" );
+ } elseif ( isset( $this->mConns['foreignFree'][$i][$wiki] ) ) {
+ // Reuse a free connection for the same wiki
+ $conn = $this->mConns['foreignFree'][$i][$wiki];
+ unset( $this->mConns['foreignFree'][$i][$wiki] );
+ $this->mConns['foreignUsed'][$i][$wiki] = $conn;
+ wfDebug( __METHOD__ . ": reusing free connection $i/$wiki\n" );
+ } elseif ( !empty( $this->mConns['foreignFree'][$i] ) ) {
+ // Reuse a connection from another wiki
+ $conn = reset( $this->mConns['foreignFree'][$i] );
+ $oldWiki = key( $this->mConns['foreignFree'][$i] );
+
+ // The empty string as a DB name means "don't care".
+ // DatabaseMysqlBase::open() already handle this on connection.
+ if ( $dbName !== '' && !$conn->selectDB( $dbName ) ) {
+ $this->mLastError = "Error selecting database $dbName on server " .
+ $conn->getServer() . " from client host " . wfHostname() . "\n";
+ $this->mErrorConnection = $conn;
+ $conn = false;
+ } else {
+ $conn->tablePrefix( $prefix );
+ unset( $this->mConns['foreignFree'][$i][$oldWiki] );
+ $this->mConns['foreignUsed'][$i][$wiki] = $conn;
+ wfDebug( __METHOD__ . ": reusing free connection from $oldWiki for $wiki\n" );
+ }
+ } else {
+ // Open a new connection
+ $server = $this->mServers[$i];
+ $server['serverIndex'] = $i;
+ $server['foreignPoolRefCount'] = 0;
+ $server['foreign'] = true;
+ $conn = $this->reallyOpenConnection( $server, $dbName );
+ if ( !$conn->isOpen() ) {
+ wfDebug( __METHOD__ . ": error opening connection for $i/$wiki\n" );
+ $this->mErrorConnection = $conn;
+ $conn = false;
+ } else {
+ $conn->tablePrefix( $prefix );
+ $this->mConns['foreignUsed'][$i][$wiki] = $conn;
+ wfDebug( __METHOD__ . ": opened new connection for $i/$wiki\n" );
+ }
+ }
+
+ // Increment reference count
+ if ( $conn ) {
+ $refCount = $conn->getLBInfo( 'foreignPoolRefCount' );
+ $conn->setLBInfo( 'foreignPoolRefCount', $refCount + 1 );
+ }
+
+ return $conn;
+ }
+
+ /**
+ * Test if the specified index represents an open connection
+ *
+ * @param int $index Server index
+ * @access private
+ * @return bool
+ */
+ private function isOpen( $index ) {
+ if ( !is_integer( $index ) ) {
+ return false;
+ }
+
+ return (bool)$this->getAnyOpenConnection( $index );
+ }
+
+ /**
+ * Really opens a connection. Uncached.
+ * Returns a Database object whether or not the connection was successful.
+ * @access private
+ *
+ * @param array $server
+ * @param bool $dbNameOverride
+ * @throws MWException
+ * @return DatabaseBase
+ */
+ protected function reallyOpenConnection( $server, $dbNameOverride = false ) {
+ if ( !is_array( $server ) ) {
+ throw new MWException( 'You must update your load-balancing configuration. ' .
+ 'See DefaultSettings.php entry for $wgDBservers.' );
+ }
+
+ if ( $dbNameOverride !== false ) {
+ $server['dbname'] = $dbNameOverride;
+ }
+
+ // Log when many connection are made on requests
+ if ( ++$this->connsOpened >= self::CONN_HELD_WARN_THRESHOLD ) {
+ $masterAddr = $this->getServerName( 0 );
+ wfDebugLog( 'DBPerformance', __METHOD__ . ": " .
+ "{$this->connsOpened}+ connections made (master=$masterAddr)\n" .
+ wfBacktrace( true ) );
+ }
+
+ # Create object
+ try {
+ $db = DatabaseBase::factory( $server['type'], $server );
+ } catch ( DBConnectionError $e ) {
+ // FIXME: This is probably the ugliest thing I have ever done to
+ // PHP. I'm half-expecting it to segfault, just out of disgust. -- TS
+ $db = $e->db;
+ }
+
+ $db->setLBInfo( $server );
+ if ( isset( $server['fakeSlaveLag'] ) ) {
+ $db->setFakeSlaveLag( $server['fakeSlaveLag'] );
+ }
+ if ( isset( $server['fakeMaster'] ) ) {
+ $db->setFakeMaster( true );
+ }
+
+ return $db;
+ }
+
+ /**
+ * @throws DBConnectionError
+ * @return bool
+ */
+ private function reportConnectionError() {
+ $conn = $this->mErrorConnection; // The connection which caused the error
+ $context = array(
+ 'method' => __METHOD__,
+ 'last_error' => $this->mLastError,
+ );
+
+ if ( !is_object( $conn ) ) {
+ // No last connection, probably due to all servers being too busy
+ wfLogDBError(
+ "LB failure with no last connection. Connection error: {last_error}",
+ $context
+ );
+
+ // If all servers were busy, mLastError will contain something sensible
+ throw new DBConnectionError( null, $this->mLastError );
+ } else {
+ $context['db_server'] = $conn->getProperty( 'mServer' );
+ wfLogDBError(
+ "Connection error: {last_error} ({db_server})",
+ $context
+ );
+ $conn->reportConnectionError( "{$this->mLastError} ({$context['db_server']})" ); // throws DBConnectionError
+ }
+
+ return false; /* not reached */
+ }
+
+ /**
+ * @return int
+ * @since 1.26
+ */
+ public function getWriterIndex() {
+ return 0;
+ }
+
+ /**
+ * Returns true if the specified index is a valid server index
+ *
+ * @param string $i
+ * @return bool
+ */
+ public function haveIndex( $i ) {
+ return array_key_exists( $i, $this->mServers );
+ }
+
+ /**
+ * Returns true if the specified index is valid and has non-zero load
+ *
+ * @param string $i
+ * @return bool
+ */
+ public function isNonZeroLoad( $i ) {
+ return array_key_exists( $i, $this->mServers ) && $this->mLoads[$i] != 0;
+ }
+
+ /**
+ * Get the number of defined servers (not the number of open connections)
+ *
+ * @return int
+ */
+ public function getServerCount() {
+ return count( $this->mServers );
+ }
+
+ /**
+ * Get the host name or IP address of the server with the specified index
+ * Prefer a readable name if available.
+ * @param string $i
+ * @return string
+ */
+ public function getServerName( $i ) {
+ if ( isset( $this->mServers[$i]['hostName'] ) ) {
+ $name = $this->mServers[$i]['hostName'];
+ } elseif ( isset( $this->mServers[$i]['host'] ) ) {
+ $name = $this->mServers[$i]['host'];
+ } else {
+ $name = '';
+ }
+
+ return ( $name != '' ) ? $name : 'localhost';
+ }
+
+ /**
+ * Return the server info structure for a given index, or false if the index is invalid.
+ * @param int $i
+ * @return array|bool
+ */
+ public function getServerInfo( $i ) {
+ if ( isset( $this->mServers[$i] ) ) {
+ return $this->mServers[$i];
+ } else {
+ return false;
+ }
+ }
+
+ /**
+ * Sets the server info structure for the given index. Entry at index $i
+ * is created if it doesn't exist
+ * @param int $i
+ * @param array $serverInfo
+ */
+ public function setServerInfo( $i, array $serverInfo ) {
+ $this->mServers[$i] = $serverInfo;
+ }
+
+ /**
+ * Get the current master position for chronology control purposes
+ * @return mixed
+ */
+ public function getMasterPos() {
+ # If this entire request was served from a slave without opening a connection to the
+ # master (however unlikely that may be), then we can fetch the position from the slave.
+ $masterConn = $this->getAnyOpenConnection( 0 );
+ if ( !$masterConn ) {
+ $serverCount = count( $this->mServers );
+ for ( $i = 1; $i < $serverCount; $i++ ) {
+ $conn = $this->getAnyOpenConnection( $i );
+ if ( $conn ) {
+ wfDebug( "Master pos fetched from slave\n" );
+
+ return $conn->getSlavePos();
+ }
+ }
+ } else {
+ wfDebug( "Master pos fetched from master\n" );
+
+ return $masterConn->getMasterPos();
+ }
+
+ return false;
+ }
+
+ /**
+ * Close all open connections
+ */
+ public function closeAll() {
+ foreach ( $this->mConns as $conns2 ) {
+ foreach ( $conns2 as $conns3 ) {
+ /** @var DatabaseBase $conn */
+ foreach ( $conns3 as $conn ) {
+ $conn->close();
+ }
+ }
+ }
+ $this->mConns = array(
+ 'local' => array(),
+ 'foreignFree' => array(),
+ 'foreignUsed' => array(),
+ );
+ $this->connsOpened = 0;
+ }
+
+ /**
+ * Close a connection
+ * Using this function makes sure the LoadBalancer knows the connection is closed.
+ * If you use $conn->close() directly, the load balancer won't update its state.
+ * @param DatabaseBase $conn
+ */
+ public function closeConnection( $conn ) {
+ $done = false;
+ foreach ( $this->mConns as $i1 => $conns2 ) {
+ foreach ( $conns2 as $i2 => $conns3 ) {
+ foreach ( $conns3 as $i3 => $candidateConn ) {
+ if ( $conn === $candidateConn ) {
+ $conn->close();
+ unset( $this->mConns[$i1][$i2][$i3] );
+ --$this->connsOpened;
+ $done = true;
+ break;
+ }
+ }
+ }
+ }
+ if ( !$done ) {
+ $conn->close();
+ }
+ }
+
+ /**
+ * Commit transactions on all open connections
+ */
+ public function commitAll() {
+ foreach ( $this->mConns as $conns2 ) {
+ foreach ( $conns2 as $conns3 ) {
+ /** @var DatabaseBase[] $conns3 */
+ foreach ( $conns3 as $conn ) {
+ if ( $conn->trxLevel() ) {
+ $conn->commit( __METHOD__, 'flush' );
+ }
+ }
+ }
+ }
+ }
+
+ /**
+ * Issue COMMIT only on master, only if queries were done on connection
+ */
+ public function commitMasterChanges() {
+ $masterIndex = $this->getWriterIndex();
+ foreach ( $this->mConns as $conns2 ) {
+ if ( empty( $conns2[$masterIndex] ) ) {
+ continue;
+ }
+ /** @var DatabaseBase $conn */
+ foreach ( $conns2[$masterIndex] as $conn ) {
+ if ( $conn->trxLevel() && $conn->writesOrCallbacksPending() ) {
+ $conn->commit( __METHOD__, 'flush' );
+ }
+ }
+ }
+ }
+
+ /**
+ * Issue ROLLBACK only on master, only if queries were done on connection
+ * @since 1.23
+ */
+ public function rollbackMasterChanges() {
+ $failedServers = array();
+
+ $masterIndex = $this->getWriterIndex();
+ foreach ( $this->mConns as $conns2 ) {
+ if ( empty( $conns2[$masterIndex] ) ) {
+ continue;
+ }
+ /** @var DatabaseBase $conn */
+ foreach ( $conns2[$masterIndex] as $conn ) {
+ if ( $conn->trxLevel() && $conn->writesOrCallbacksPending() ) {
+ try {
+ $conn->rollback( __METHOD__, 'flush' );
+ } catch ( DBError $e ) {
+ MWExceptionHandler::logException( $e );
+ $failedServers[] = $conn->getServer();
+ }
+ }
+ }
+ }
+
+ if ( $failedServers ) {
+ throw new DBExpectedError( null, "Rollback failed on server(s) " .
+ implode( ', ', array_unique( $failedServers ) ) );
+ }
+ }
+
+ /**
+ * @return bool Whether a master connection is already open
+ * @since 1.24
+ */
+ public function hasMasterConnection() {
+ return $this->isOpen( $this->getWriterIndex() );
+ }
+
+ /**
+ * Determine if there are pending changes in a transaction by this thread
+ * @since 1.23
+ * @return bool
+ */
+ public function hasMasterChanges() {
+ $masterIndex = $this->getWriterIndex();
+ foreach ( $this->mConns as $conns2 ) {
+ if ( empty( $conns2[$masterIndex] ) ) {
+ continue;
+ }
+ /** @var DatabaseBase $conn */
+ foreach ( $conns2[$masterIndex] as $conn ) {
+ if ( $conn->trxLevel() && $conn->writesOrCallbacksPending() ) {
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Get the timestamp of the latest write query done by this thread
+ * @since 1.25
+ * @return float|bool UNIX timestamp or false
+ */
+ public function lastMasterChangeTimestamp() {
+ $lastTime = false;
+ $masterIndex = $this->getWriterIndex();
+ foreach ( $this->mConns as $conns2 ) {
+ if ( empty( $conns2[$masterIndex] ) ) {
+ continue;
+ }
+ /** @var DatabaseBase $conn */
+ foreach ( $conns2[$masterIndex] as $conn ) {
+ $lastTime = max( $lastTime, $conn->lastDoneWrites() );
+ }
+ }
+ return $lastTime;
+ }
+
+ /**
+ * Check if this load balancer object had any recent or still
+ * pending writes issued against it by this PHP thread
+ *
+ * @param float $age How many seconds ago is "recent" [defaults to mWaitTimeout]
+ * @return bool
+ * @since 1.25
+ */
+ public function hasOrMadeRecentMasterChanges( $age = null ) {
+ $age = ( $age === null ) ? $this->mWaitTimeout : $age;
+
+ return ( $this->hasMasterChanges()
+ || $this->lastMasterChangeTimestamp() > microtime( true ) - $age );
+ }
+
+ /**
+ * @param mixed $value
+ * @return mixed
+ */
+ public function waitTimeout( $value = null ) {
+ return wfSetVar( $this->mWaitTimeout, $value );
+ }
+
+ /**
+ * @return bool Whether the generic connection for reads is highly "lagged"
+ */
+ public function getLaggedSlaveMode() {
+ # Get a generic reader connection
+ $this->getConnection( DB_SLAVE );
+
+ return $this->mLaggedSlaveMode;
+ }
+
+ /**
+ * Disables/enables lag checks
+ * @param null|bool $mode
+ * @return bool
+ */
+ public function allowLagged( $mode = null ) {
+ if ( $mode === null ) {
+ return $this->mAllowLagged;
+ }
+ $this->mAllowLagged = $mode;
+
+ return $this->mAllowLagged;
+ }
+
+ /**
+ * @return bool
+ */
+ public function pingAll() {
+ $success = true;
+ foreach ( $this->mConns as $conns2 ) {
+ foreach ( $conns2 as $conns3 ) {
+ /** @var DatabaseBase[] $conns3 */
+ foreach ( $conns3 as $conn ) {
+ if ( !$conn->ping() ) {
+ $success = false;
+ }
+ }
+ }
+ }
+
+ return $success;
+ }
+
+ /**
+ * Call a function with each open connection object
+ * @param callable $callback
+ * @param array $params
+ */
+ public function forEachOpenConnection( $callback, array $params = array() ) {
+ foreach ( $this->mConns as $conns2 ) {
+ foreach ( $conns2 as $conns3 ) {
+ foreach ( $conns3 as $conn ) {
+ $mergedParams = array_merge( array( $conn ), $params );
+ call_user_func_array( $callback, $mergedParams );
+ }
+ }
+ }
+ }
+
+ /**
+ * Get the hostname and lag time of the most-lagged slave
+ *
+ * This is useful for maintenance scripts that need to throttle their updates.
+ * May attempt to open connections to slaves on the default DB. If there is
+ * no lag, the maximum lag will be reported as -1.
+ *
+ * @param bool|string $wiki Wiki ID, or false for the default database
+ * @return array ( host, max lag, index of max lagged host )
+ */
+ public function getMaxLag( $wiki = false ) {
+ $maxLag = -1;
+ $host = '';
+ $maxIndex = 0;
+
+ if ( $this->getServerCount() <= 1 ) {
+ return array( $host, $maxLag, $maxIndex ); // no replication = no lag
+ }
+
+ $lagTimes = $this->getLagTimes( $wiki );
+ foreach ( $lagTimes as $i => $lag ) {
+ if ( $lag > $maxLag ) {
+ $maxLag = $lag;
+ $host = $this->mServers[$i]['host'];
+ $maxIndex = $i;
+ }
+ }
+
+ return array( $host, $maxLag, $maxIndex );
+ }
+
+ /**
+ * Get lag time for each server
+ *
+ * Results are cached for a short time in memcached/process cache
+ *
+ * @param string|bool $wiki
+ * @return int[] Map of (server index => seconds)
+ */
+ public function getLagTimes( $wiki = false ) {
+ if ( $this->getServerCount() <= 1 ) {
+ return array( 0 => 0 ); // no replication = no lag
+ }
+
+ # Send the request to the load monitor
+ return $this->getLoadMonitor()->getLagTimes( array_keys( $this->mServers ), $wiki );
+ }
+
+ /**
+ * Get the lag in seconds for a given connection, or zero if this load
+ * balancer does not have replication enabled.
+ *
+ * This should be used in preference to Database::getLag() in cases where
+ * replication may not be in use, since there is no way to determine if
+ * replication is in use at the connection level without running
+ * potentially restricted queries such as SHOW SLAVE STATUS. Using this
+ * function instead of Database::getLag() avoids a fatal error in this
+ * case on many installations.
+ *
+ * @param DatabaseBase $conn
+ * @return int
+ */
+ public function safeGetLag( $conn ) {
+ if ( $this->getServerCount() == 1 ) {
+ return 0;
+ } else {
+ return $conn->getLag();
+ }
+ }
+
+ /**
+ * Clear the cache for slag lag delay times
+ *
+ * This is only used for testing
+ */
+ public function clearLagTimeCache() {
+ $this->getLoadMonitor()->clearCaches();
+ }
+}
--- /dev/null
+<?php
+/**
+ * Database load monitoring.
+ *
+ * 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
+ */
+
+/**
+ * An interface for database load monitoring
+ *
+ * @ingroup Database
+ */
+interface LoadMonitor {
+ /**
+ * Construct a new LoadMonitor with a given LoadBalancer parent
+ *
+ * @param LoadBalancer $parent
+ */
+ public function __construct( $parent );
+
+ /**
+ * Perform pre-connection load ratio adjustment.
+ * @param array $loads
+ * @param string|bool $group The selected query group. Default: false
+ * @param string|bool $wiki Default: false
+ */
+ public function scaleLoads( &$loads, $group = false, $wiki = false );
+
+ /**
+ * Return an estimate of replication lag for each server
+ *
+ * @param array $serverIndexes
+ * @param string $wiki
+ *
+ * @return array Map of (server index => seconds)
+ */
+ public function getLagTimes( $serverIndexes, $wiki );
+}
+
+class LoadMonitorNull implements LoadMonitor {
+ public function __construct( $parent ) {
+ }
+
+ public function scaleLoads( &$loads, $group = false, $wiki = false ) {
+ }
+
+ public function getLagTimes( $serverIndexes, $wiki ) {
+ return array_fill_keys( $serverIndexes, 0 );
+ }
+}
--- /dev/null
+<?php
+/**
+ * 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
+ */
+
+/**
+ * Basic MySQL load monitor with no external dependencies
+ * Uses memcached to cache the replication lag for a short time
+ *
+ * @ingroup Database
+ */
+class LoadMonitorMySQL implements LoadMonitor {
+ /** @var LoadBalancer */
+ public $parent;
+ /** @var BagOStuff */
+ protected $srvCache;
+ /** @var BagOStuff */
+ protected $mainCache;
+
+ public function __construct( $parent ) {
+ $this->parent = $parent;
+
+ $this->srvCache = ObjectCache::newAccelerator( 'hash' );
+ $this->mainCache = wfGetMainCache();
+ }
+
+ public function scaleLoads( &$loads, $group = false, $wiki = false ) {
+ }
+
+ public function getLagTimes( $serverIndexes, $wiki ) {
+ if ( count( $serverIndexes ) == 1 && reset( $serverIndexes ) == 0 ) {
+ # Single server only, just return zero without caching
+ return array( 0 => 0 );
+ }
+
+ $key = $this->getLagTimeCacheKey();
+ # Randomize TTLs to reduce stampedes (4.0 - 5.0 sec)
+ $ttl = mt_rand( 4e6, 5e6 ) / 1e6;
+ # Keep keys around longer as fallbacks
+ $staleTTL = 60;
+
+ # (a) Check the local APC cache
+ $value = $this->srvCache->get( $key );
+ if ( $value && $value['timestamp'] > ( microtime( true ) - $ttl ) ) {
+ wfDebugLog( 'replication', __FUNCTION__ . ": got lag times ($key) from local cache" );
+ return $value['lagTimes']; // cache hit
+ }
+ $staleValue = $value ?: false;
+
+ # (b) Check the shared cache and backfill APC
+ $value = $this->mainCache->get( $key );
+ if ( $value && $value['timestamp'] > ( microtime( true ) - $ttl ) ) {
+ $this->srvCache->set( $key, $value, $staleTTL );
+ wfDebugLog( 'replication', __FUNCTION__ . ": got lag times ($key) from main cache" );
+
+ return $value['lagTimes']; // cache hit
+ }
+ $staleValue = $value ?: $staleValue;
+
+ # (c) Cache key missing or expired; regenerate and backfill
+ if ( $this->mainCache->lock( $key, 0, 10 ) ) {
+ # Let this process alone update the cache value
+ $cache = $this->mainCache;
+ /** @noinspection PhpUnusedLocalVariableInspection */
+ $unlocker = new ScopedCallback( function () use ( $cache, $key ) {
+ $cache->unlock( $key );
+ } );
+ } elseif ( $staleValue ) {
+ # Could not acquire lock but an old cache exists, so use it
+ return $staleValue['lagTimes'];
+ }
+
+ $lagTimes = array();
+ foreach ( $serverIndexes as $i ) {
+ if ( $i == 0 ) { # Master
+ $lagTimes[$i] = 0;
+ } elseif ( false !== ( $conn = $this->parent->getAnyOpenConnection( $i ) ) ) {
+ $lagTimes[$i] = $conn->getLag();
+ } elseif ( false !== ( $conn = $this->parent->openConnection( $i, $wiki ) ) ) {
+ $lagTimes[$i] = $conn->getLag();
+ # Close the connection to avoid sleeper connections piling up.
+ # Note that the caller will pick one of these DBs and reconnect,
+ # which is slightly inefficient, but this only matters for the lag
+ # time cache miss cache, which is far less common that cache hits.
+ $this->parent->closeConnection( $conn );
+ }
+ }
+
+ # Add a timestamp key so we know when it was cached
+ $value = array( 'lagTimes' => $lagTimes, 'timestamp' => microtime( true ) );
+ $this->mainCache->set( $key, $value, $staleTTL );
+ $this->srvCache->set( $key, $value, $staleTTL );
+ wfDebugLog( 'replication', __FUNCTION__ . ": re-calculated lag times ($key)" );
+
+ return $value['lagTimes'];
+ }
+
+ public function clearCaches() {
+ $key = $this->getLagTimeCacheKey();
+ $this->srvCache->delete( $key );
+ $this->mainCache->delete( $key );
+ }
+
+ private function getLagTimeCacheKey() {
+ # Lag is per-server, not per-DB, so key on the master DB name
+ return wfGlobalCacheKey( 'lag-times', $this->parent->getServerName( 0 ) );
+ }
+}
dépôts / lhc / web / wiklou.git / commitdiff