+++ /dev/null
-<?php
-/**
- * Database load balancing
- *
- * @file
- * @ingroup Database
- */
-
-/**
- * Database load balancing object
- *
- * @todo document
- * @ingroup Database
- */
-class LoadBalancer {
- /* private */ var $mServers, $mConns, $mLoads, $mGroupLoads;
- /* private */ var $mErrorConnection;
- /* private */ var $mReadIndex, $mAllowLagged;
- /* private */ var $mWaitForPos, $mWaitTimeout;
- /* private */ var $mLaggedSlaveMode, $mLastError = 'Unknown error';
- /* private */ var $mParentInfo, $mLagTimes;
- /* private */ var $mLoadMonitorClass, $mLoadMonitor;
-
- /**
- * @param $params Array with keys:
- * servers Required. Array of server info structures.
- * masterWaitTimeout Replication lag wait timeout
- * loadMonitor Name of a class used to fetch server lag and load.
- */
- function __construct( $params )
- {
- if ( !isset( $params['servers'] ) ) {
- throw new MWException( __CLASS__.': missing servers parameter' );
- }
- $this->mServers = $params['servers'];
-
- if ( isset( $params['waitTimeout'] ) ) {
- $this->mWaitTimeout = $params['waitTimeout'];
- } else {
- $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;
- $this->mLoadMonitorClass = isset( $params['loadMonitor'] )
- ? $params['loadMonitor'] : 'LoadMonitor_MySQL';
-
- 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
- */
- 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
- */
- 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
- */
- function pickRandom( $weights )
- {
- if ( !is_array( $weights ) || count( $weights ) == 0 ) {
- return false;
- }
-
- $sum = array_sum( $weights );
- if ( $sum == 0 ) {
- # No loads on any of them
- # In previous versions, this triggered an unweighted random selection,
- # but this feature has been removed as of April 2006 to allow for strict
- # separation of query groups.
- return false;
- }
- $max = mt_getrandmax();
- $rand = mt_rand(0, $max) / $max * $sum;
-
- $sum = 0;
- foreach ( $weights as $i => $w ) {
- $sum += $w;
- if ( $sum >= $rand ) {
- break;
- }
- }
- return $i;
- }
-
- function getRandomNonLagged( $loads, $wiki = false ) {
- # Unset excessively lagged servers
- $lags = $this->getLagTimes( $wiki );
- foreach ( $lags as $i => $lag ) {
- if ( $i != 0 ) {
- if ( $lag === false ) {
- wfDebug( "Server #$i is not replicating\n" );
- unset( $loads[$i] );
- } elseif ( isset( $this->mServers[$i]['max lag'] ) && $lag > $this->mServers[$i]['max lag'] ) {
- wfDebug( "Server #$i is excessively lagged ($lag seconds)\n" );
- 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 $this->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
- */
- function getReaderIndex( $group = false, $wiki = false ) {
- global $wgReadOnly, $wgDBClusterTimeout, $wgDBAvgStatusPoll, $wgDBtype;
-
- # FIXME: For now, only go through all this for mysql databases
- if ($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 and $this->mReadIndex >= 0 ) {
- # Shortcut if generic reader exists already
- return $this->mReadIndex;
- }
-
- wfProfileIn( __METHOD__ );
-
- $totalElapsed = 0;
-
- # convert from seconds to microseconds
- $timeout = $wgDBClusterTimeout * 1e6;
-
- # 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" );
- wfProfileOut( __METHOD__ );
- return false;
- }
- } else {
- $nonErrorLoads = $this->mLoads;
- }
-
- if ( !$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;
-
- # First try quickly looking through the available servers for a server that
- # meets our criteria
- do {
- $totalThreadsConnected = 0;
- $overloadedServers = 0;
- $currentLoads = $nonErrorLoads;
- while ( count( $currentLoads ) ) {
- if ( $wgReadOnly || $this->mAllowLagged || $laggedSlaveMode ) {
- $i = $this->pickRandom( $currentLoads );
- } else {
- $i = $this->getRandomNonLagged( $currentLoads, $wiki );
- if ( $i === false && count( $currentLoads ) != 0 ) {
- # All slaves lagged. Switch to read-only mode
- $wgReadOnly = 'The database has been automatically locked ' .
- 'while the slave database servers catch up to the master';
- $i = $this->pickRandom( $currentLoads );
- $laggedSlaveMode = true;
- }
- }
-
- if ( $i === false ) {
- # pickRandom() returned false
- # This is permanent and means the configuration or the load monitor
- # wants us to return false.
- wfDebugLog( 'connect', __METHOD__.": pickRandom() returned false\n" );
- wfProfileOut( __METHOD__ );
- return false;
- }
-
- wfDebugLog( 'connect', __METHOD__.": Using reader #$i: {$this->mServers[$i]['host']}...\n" );
- $conn = $this->openConnection( $i, $wiki );
-
- if ( !$conn ) {
- wfDebugLog( 'connect', __METHOD__.": Failed connecting to $i/$wiki\n" );
- unset( $nonErrorLoads[$i] );
- unset( $currentLoads[$i] );
- continue;
- }
-
- // Perform post-connection backoff
- $threshold = isset( $this->mServers[$i]['max threads'] )
- ? $this->mServers[$i]['max threads'] : false;
- $backoff = $this->getLoadMonitor()->postConnectionBackoff( $conn, $threshold );
-
- // Decrement reference counter, we are finished with this connection.
- // It will be incremented for the caller later.
- if ( $wiki !== false ) {
- $this->reuseConnection( $conn );
- }
-
- if ( $backoff ) {
- # Post-connection overload, don't use this server for now
- $totalThreadsConnected += $backoff;
- $overloadedServers++;
- unset( $currentLoads[$i] );
- } else {
- # Return this server
- break 2;
- }
- }
-
- # No server found yet
- $i = false;
-
- # If all servers were down, quit now
- if ( !count( $nonErrorLoads ) ) {
- wfDebugLog( 'connect', "All servers down\n" );
- break;
- }
-
- # Some servers must have been overloaded
- if ( $overloadedServers == 0 ) {
- throw new MWException( __METHOD__.": unexpectedly found no overloaded servers" );
- }
- # Back off for a while
- # Scale the sleep time by the number of connected threads, to produce a
- # roughly constant global poll rate
- $avgThreads = $totalThreadsConnected / $overloadedServers;
- $totalElapsed += $this->sleep( $wgDBAvgStatusPoll * $avgThreads );
- } while ( $totalElapsed < $timeout );
-
- if ( $totalElapsed >= $timeout ) {
- wfDebugLog( 'connect', "All servers busy\n" );
- $this->mErrorConnection = false;
- $this->mLastError = 'All servers busy';
- }
-
- 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 && $i !== false ) {
- $this->mReadIndex = $i;
- }
- }
- wfProfileOut( __METHOD__ );
- return $i;
- }
-
- /**
- * Wait for a specified number of microseconds, and return the period waited
- */
- function sleep( $t ) {
- wfProfileIn( __METHOD__ );
- wfDebug( __METHOD__.": waiting $t us\n" );
- usleep( $t );
- wfProfileOut( __METHOD__ );
- return $t;
- }
-
- /**
- * 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
- */
- public function waitFor( $pos ) {
- wfProfileIn( __METHOD__ );
- $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;
- }
- }
- wfProfileOut( __METHOD__ );
- }
-
- /**
- * Set the master wait position and wait for ALL slaves to catch up to it
- */
- public function waitForAll( $pos ) {
- wfProfileIn( __METHOD__ );
- $this->mWaitForPos = $pos;
- for ( $i = 1; $i < count( $this->mServers ); $i++ ) {
- $this->doWait( $i );
- }
- wfProfileOut( __METHOD__ );
- }
-
- /**
- * Get any open connection to a given server index, local or foreign
- * Returns false if there is no connection open
- */
- 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
- */
- function doWait( $index ) {
- # Find a connection to wait on
- $conn = $this->getAnyOpenConnection( $index );
- if ( !$conn ) {
- wfDebug( __METHOD__ . ": no connection open\n" );
- return false;
- }
-
- wfDebug( __METHOD__.": Waiting for slave #$index to catch up...\n" );
- $result = $conn->masterPosWait( $this->mWaitForPos, $this->mWaitTimeout );
-
- if ( $result == -1 || is_null( $result ) ) {
- # Timed out waiting for slave, use master instead
- wfDebug( __METHOD__.": Timed out waiting for slave #$index pos {$this->mWaitForPos}\n" );
- return false;
- } else {
- wfDebug( __METHOD__.": Done\n" );
- return true;
- }
- }
-
- /**
- * Get a connection by index
- * This is the main entry point for this class.
- *
- * @param $i Integer: server index
- * @param $groups Array: query groups
- * @param $wiki String: wiki ID
- *
- * @return DatabaseBase
- */
- public function &getConnection( $i, $groups = array(), $wiki = false ) {
- wfProfileIn( __METHOD__ );
-
- if ( $i == DB_LAST ) {
- throw new MWException( 'Attempt to call ' . __METHOD__ . ' with deprecated server index DB_LAST' );
- } elseif ( $i === null || $i === false ) {
- throw new MWException( 'Attempt to call ' . __METHOD__ . ' with invalid server index' );
- }
-
- if ( $wiki === wfWikiID() ) {
- $wiki = false;
- }
-
- # Query groups
- if ( $i == DB_MASTER ) {
- $i = $this->getWriterIndex();
- } elseif ( !is_array( $groups ) ) {
- $groupIndex = $this->getReaderIndex( $groups, $wiki );
- if ( $groupIndex !== false ) {
- $serverName = $this->getServerName( $groupIndex );
- wfDebug( __METHOD__.": using server $serverName for group $groups\n" );
- $i = $groupIndex;
- }
- } else {
- foreach ( $groups as $group ) {
- $groupIndex = $this->getReaderIndex( $group, $wiki );
- if ( $groupIndex !== false ) {
- $serverName = $this->getServerName( $groupIndex );
- wfDebug( __METHOD__.": using server $serverName for group $group\n" );
- $i = $groupIndex;
- break;
- }
- }
- }
-
- # Operation-based index
- if ( $i == DB_SLAVE ) {
- $i = $this->getReaderIndex( false, $wiki );
- # Couldn't find a working server in getReaderIndex()?
- if ( $i === false ) {
- $this->mLastError = 'No working slave server: ' . $this->mLastError;
- $this->reportConnectionError( $this->mErrorConnection );
- wfProfileOut( __METHOD__ );
- return false;
- }
- }
-
- # Now we have an explicit index into the servers array
- $conn = $this->openConnection( $i, $wiki );
- if ( !$conn ) {
- $this->reportConnectionError( $this->mErrorConnection );
- }
-
- wfProfileOut( __METHOD__ );
- 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.
- */
- public function reuseConnection( $conn ) {
- $serverIndex = $conn->getLBInfo('serverIndex');
- $refCount = $conn->getLBInfo('foreignPoolRefCount');
- $dbName = $conn->getDBname();
- $prefix = $conn->tablePrefix();
- if ( strval( $prefix ) !== '' ) {
- $wiki = "$dbName-$prefix";
- } else {
- $wiki = $dbName;
- }
- 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;
- }
- 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" );
- }
- }
-
- /**
- * 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 $i Integer: server index
- * @param $wiki String: wiki ID to open
- * @return DatabaseBase
- *
- * @access private
- */
- function openConnection( $i, $wiki = false ) {
- wfProfileIn( __METHOD__ );
- if ( $wiki !== false ) {
- $conn = $this->openForeignConnection( $i, $wiki );
- wfProfileOut( __METHOD__);
- return $conn;
- }
- if ( 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 );
- if ( $conn->isOpen() ) {
- $this->mConns['local'][$i][0] = $conn;
- } else {
- wfDebug( "Failed to connect to database $i at {$this->mServers[$i]['host']}\n" );
- $this->mErrorConnection = $conn;
- $conn = false;
- }
- }
- wfProfileOut( __METHOD__ );
- 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 $i Integer: server index
- * @param $wiki String: wiki ID to open
- * @return DatabaseBase
- */
- function openForeignConnection( $i, $wiki ) {
- wfProfileIn(__METHOD__);
- 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] );
-
- if ( !$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;
- $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 );
- }
- wfProfileOut(__METHOD__);
- return $conn;
- }
-
- /**
- * Test if the specified index represents an open connection
- *
- * @param $index Integer: server index
- * @access 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
- */
- 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.' );
- }
-
- $host = $server['host'];
- $dbname = $server['dbname'];
-
- if ( $dbNameOverride !== false ) {
- $server['dbname'] = $dbname = $dbNameOverride;
- }
-
- # Create object
- wfDebug( "Connecting to $host $dbname...\n" );
- try {
- $db = DatabaseBase::newFromType( $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;
- }
- if ( $db->isOpen() ) {
- wfDebug( "Connected to $host $dbname.\n" );
- } else {
- wfDebug( "Connection failed to $host $dbname.\n" );
- }
- $db->setLBInfo( $server );
- if ( isset( $server['fakeSlaveLag'] ) ) {
- $db->setFakeSlaveLag( $server['fakeSlaveLag'] );
- }
- if ( isset( $server['fakeMaster'] ) ) {
- $db->setFakeMaster( true );
- }
- return $db;
- }
-
- function reportConnectionError( &$conn ) {
- wfProfileIn( __METHOD__ );
-
- if ( !is_object( $conn ) ) {
- // No last connection, probably due to all servers being too busy
- wfLogDBError( "LB failure with no last connection\n" );
- $conn = new Database;
- // If all servers were busy, mLastError will contain something sensible
- throw new DBConnectionError( $conn, $this->mLastError );
- } else {
- $server = $conn->getProperty( 'mServer' );
- wfLogDBError( "Connection error: {$this->mLastError} ({$server})\n" );
- $conn->reportConnectionError( "{$this->mLastError} ({$server})" );
- }
- wfProfileOut( __METHOD__ );
- }
-
- function getWriterIndex() {
- return 0;
- }
-
- /**
- * Returns true if the specified index is a valid server index
- */
- function haveIndex( $i ) {
- return array_key_exists( $i, $this->mServers );
- }
-
- /**
- * Returns true if the specified index is valid and has non-zero load
- */
- 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)
- */
- 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.
- */
- function getServerName( $i ) {
- if ( isset( $this->mServers[$i]['hostName'] ) ) {
- return $this->mServers[$i]['hostName'];
- } elseif ( isset( $this->mServers[$i]['host'] ) ) {
- return $this->mServers[$i]['host'];
- } else {
- return '';
- }
- }
-
- /**
- * Return the server info structure for a given index, or false if the index is invalid.
- */
- function getServerInfo( $i ) {
- if ( isset( $this->mServers[$i] ) ) {
- return $this->mServers[$i];
- } else {
- return false;
- }
- }
-
- /**
- * Get the current master position for chronology control purposes
- * @return mixed
- */
- 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 ) {
- for ( $i = 1; $i < count( $this->mServers ); $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
- */
- function closeAll() {
- foreach ( $this->mConns as $conns2 ) {
- foreach ( $conns2 as $conns3 ) {
- foreach ( $conns3 as $conn ) {
- $conn->close();
- }
- }
- }
- $this->mConns = array(
- 'local' => array(),
- 'foreignFree' => array(),
- 'foreignUsed' => array(),
- );
- }
-
- /**
- * Deprecated function, typo in function name
- */
- function closeConnecton( $conn ) {
- $this->closeConnection( $conn );
- }
-
- /**
- * 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 $conn
- * @return void
- */
- 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] );
- $done = true;
- break;
- }
- }
- }
- }
- if ( !$done ) {
- $conn->close();
- }
- }
-
- /**
- * Commit transactions on all open connections
- */
- function commitAll() {
- foreach ( $this->mConns as $conns2 ) {
- foreach ( $conns2 as $conns3 ) {
- foreach ( $conns3 as $conn ) {
- $conn->commit();
- }
- }
- }
- }
-
- /* Issue COMMIT only on master, only if queries were done on connection */
- function commitMasterChanges() {
- // Always 0, but who knows.. :)
- $masterIndex = $this->getWriterIndex();
- foreach ( $this->mConns as $conns2 ) {
- if ( empty( $conns2[$masterIndex] ) ) {
- continue;
- }
- foreach ( $conns2[$masterIndex] as $conn ) {
- if ( $conn->doneWrites() ) {
- $conn->commit();
- }
- }
- }
- }
-
- function waitTimeout( $value = null ) {
- return wfSetVar( $this->mWaitTimeout, $value );
- }
-
- function getLaggedSlaveMode() {
- return $this->mLaggedSlaveMode;
- }
-
- /* Disables/enables lag checks */
- function allowLagged($mode=null) {
- if ($mode===null)
- return $this->mAllowLagged;
- $this->mAllowLagged=$mode;
- }
-
- function pingAll() {
- $success = true;
- foreach ( $this->mConns as $conns2 ) {
- foreach ( $conns2 as $conns3 ) {
- foreach ( $conns3 as $conn ) {
- if ( !$conn->ping() ) {
- $success = false;
- }
- }
- }
- }
- return $success;
- }
-
- /**
- * Call a function with each open connection object
- */
- function forEachOpenConnection( $callback, $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.
- * @param $wiki string Wiki ID, or false for the default database
- */
- function getMaxLag( $wiki = false ) {
- $maxLag = -1;
- $host = '';
- foreach ( $this->mServers as $i => $conn ) {
- $conn = false;
- if ( $wiki === false ) {
- $conn = $this->getAnyOpenConnection( $i );
- }
- if ( !$conn ) {
- $conn = $this->openConnection( $i, $wiki );
- }
- if ( !$conn ) {
- continue;
- }
- $lag = $conn->getLag();
- if ( $lag > $maxLag ) {
- $maxLag = $lag;
- $host = $this->mServers[$i]['host'];
- }
- }
- return array( $host, $maxLag );
- }
-
- /**
- * Get lag time for each server
- * Results are cached for a short time in memcached, and indefinitely in the process cache
- */
- function getLagTimes( $wiki = false ) {
- # Try process cache
- if ( isset( $this->mLagTimes ) ) {
- return $this->mLagTimes;
- }
- # No, send the request to the load monitor
- $this->mLagTimes = $this->getLoadMonitor()->getLagTimes( array_keys( $this->mServers ), $wiki );
- return $this->mLagTimes;
- }
-
- /**
- * Clear the cache for getLagTimes
- */
- function clearLagTimeCache() {
- $this->mLagTimes = null;
- }
-}
scripts.mit.edu / autoinstallsdev / mediawiki.git / blobdiff