Gecko [ paroquia-rio-de-mouro.pt ]

Name	Size	Permission	Date
CloneDatabase.php	4.54 KB	-rw-r--r--	2016-11-28 20:20
Database.php	92.71 KB	-rw-r--r--	2011-12-09 21:31
DatabaseError.php	7.5 KB	-rw-r--r--	2011-08-27 21:28
DatabaseIbm_db2.php	40.96 KB	-rw-r--r--	2011-07-04 17:00
DatabaseMssql.php	38.48 KB	-rw-r--r--	2016-11-28 20:20
DatabaseMysql.php	20.6 KB	-rw-r--r--	2012-01-03 18:53
DatabaseOracle.php	37.85 KB	-rw-r--r--	2016-11-28 20:20
DatabasePostgres.php	25.12 KB	-rw-r--r--	2011-07-04 17:00
DatabaseSqlite.php	20.36 KB	-rw-r--r--	2011-09-08 00:07
DatabaseUtility.php	4.88 KB	-rw-r--r--	2011-08-27 21:28
LBFactory.php	9.09 KB	-rw-r--r--	2011-05-28 20:58
LBFactory_Multi.php	8.44 KB	-rw-r--r--	2011-05-28 20:58
LBFactory_Single.php	1.73 KB	-rw-r--r--	2011-05-29 16:24
LoadBalancer.php	28.31 KB	-rw-r--r--	2011-09-08 13:08
LoadMonitor.php	4.2 KB	-rw-r--r--	2011-09-07 23:56
MWLBFactory.php	6.06 KB	-rw-r--r--	2016-11-28 20:20

Rename

<?php
/**
 * Database load monitoring
 *
 * @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
	 */
	function __construct( $parent );

/**
	 * Perform pre-connection load ratio adjustment.
	 * @param $loads array
	 * @param $group String: the selected query group
	 * @param $wiki String
	 */
	function scaleLoads( &$loads, $group = false, $wiki = false );

/**
	 * Perform post-connection backoff.
	 *
	 * If the connection is in overload, this should return a backoff factor
	 * which will be used to control polling time. The number of threads
	 * connected is a good measure.
	 *
	 * If there is no overload, zero can be returned.
	 *
	 * A threshold thread count is given, the concrete class may compare this
	 * to the running thread count. The threshold may be false, which indicates
	 * that the sysadmin has not configured this feature.
	 *
	 * @param $conn DatabaseBase
	 * @param $threshold Float
	 */
	function postConnectionBackoff( $conn, $threshold );

/**
	 * Return an estimate of replication lag for each server
	 *
	 * @param $serverIndexes
	 * @param $wiki
	 *
	 * @return array
	 */
	function getLagTimes( $serverIndexes, $wiki );
}

class LoadMonitor_Null implements LoadMonitor {
	function __construct( $parent ) {
	}

function scaleLoads( &$loads, $group = false, $wiki = false ) {
	}

function postConnectionBackoff( $conn, $threshold ) {
	}

function getLagTimes( $serverIndexes, $wiki ) {
		return array_fill_keys( $serverIndexes, 0 );
	}
}

/**
 * Basic MySQL load monitor with no external dependencies
 * Uses memcached to cache the replication lag for a short time
 *
 * @ingroup Database
 */
class LoadMonitor_MySQL implements LoadMonitor {

/**
	 * @var LoadBalancer
	 */
	var $parent;

/**
	 * @param LoadBalancer $parent
	 */
	function __construct( $parent ) {
		$this->parent = $parent;
	}

/**
	 * @param $loads
	 * @param $group bool
	 * @param $wiki bool
	 */
	function scaleLoads( &$loads, $group = false, $wiki = false ) {
	}

/**
	 * @param $serverIndexes
	 * @param $wiki
	 * @return array
	 */
	function getLagTimes( $serverIndexes, $wiki ) {
		if ( count( $serverIndexes ) == 1 && reset( $serverIndexes ) == 0 ) {
			// Single server only, just return zero without caching
			return array( 0 => 0 );
		}

wfProfileIn( __METHOD__ );
		$expiry = 5;
		$requestRate = 10;

global $wgMemc;
		if ( empty( $wgMemc ) )
			$wgMemc = wfGetMainCache();

$masterName = $this->parent->getServerName( 0 );
		$memcKey = wfMemcKey( 'lag_times', $masterName );
		$times = $wgMemc->get( $memcKey );
		if ( $times ) {
			# Randomly recache with probability rising over $expiry
			$elapsed = time() - $times['timestamp'];
			$chance = max( 0, ( $expiry - $elapsed ) * $requestRate );
			if ( mt_rand( 0, $chance ) != 0 ) {
				unset( $times['timestamp'] );
				wfProfileOut( __METHOD__ );
				return $times;
			}
			wfIncrStats( 'lag_cache_miss_expired' );
		} else {
			wfIncrStats( 'lag_cache_miss_absent' );
		}

# Cache key missing or expired

$times = array();
		foreach ( $serverIndexes as $i ) {
			if ($i == 0) { # Master
				$times[$i] = 0;
			} elseif ( false !== ( $conn = $this->parent->getAnyOpenConnection( $i ) ) ) {
				$times[$i] = $conn->getLag();
			} elseif ( false !== ( $conn = $this->parent->openConnection( $i, $wiki ) ) ) {
				$times[$i] = $conn->getLag();
			}
		}

# Add a timestamp key so we know when it was cached
		$times['timestamp'] = time();
		$wgMemc->set( $memcKey, $times, $expiry );

# But don't give the timestamp to the caller
		unset($times['timestamp']);
		$lagTimes = $times;

wfProfileOut( __METHOD__ );
		return $lagTimes;
	}

/**
	 * @param $conn DatabaseBase
	 * @param $threshold
	 * @return int
	 */
	function postConnectionBackoff( $conn, $threshold ) {
		if ( !$threshold ) {
			return 0;
		}
		$status = $conn->getMysqlStatus("Thread%");
		if ( $status['Threads_running'] > $threshold ) {
			$server = $conn->getProperty( 'mServer' );
			wfLogDBError( "LB backoff from $server - Threads_running = {$status['Threads_running']}\n" );
			return $status['Threads_connected'];
		} else {
			return 0;
		}
	}
}