62fcaecee3
The only user was LoadMonitor, which is converted to only use the WAN and server caches. Previously, the lock() calls there were useless since LBFactory never injected "memcCache" to LoadBalancer, ergo making it EmptyBagOStuff in LoadMonitor. Change-Id: I0c7793d47b93b763dee478d16fb87ec637dc6cab
73 lines
2.3 KiB
PHP
73 lines
2.3 KiB
PHP
<?php
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/**
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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* @ingroup Database
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*/
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namespace Wikimedia\Rdbms;
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use BagOStuff;
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use WANObjectCache;
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/**
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* Basic MySQL load monitor with no external dependencies
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* Uses memcached to cache the replication lag for a short time
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*
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* @ingroup Database
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*/
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class LoadMonitorMySQL extends LoadMonitor {
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/** @var float What buffer pool use ratio counts as "warm" (e.g. 0.5 for 50% usage) */
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private $warmCacheRatio;
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public function __construct(
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ILoadBalancer $lb, BagOStuff $srvCache, WANObjectCache $wCache, array $options = []
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) {
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parent::__construct( $lb, $srvCache, $wCache, $options );
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$this->warmCacheRatio = isset( $options['warmCacheRatio'] )
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? $options['warmCacheRatio']
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: 0.0;
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}
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protected function getWeightScale( $index, IDatabase $conn = null ) {
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if ( !$conn ) {
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return 0.0;
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}
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$weight = 1.0;
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if ( $this->warmCacheRatio > 0 ) {
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$res = $conn->query( 'SHOW STATUS', false );
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$s = $res ? $conn->fetchObject( $res ) : false;
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if ( $s === false ) {
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$host = $this->parent->getServerName( $index );
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$this->replLogger->error( __METHOD__ . ": could not get status for $host" );
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} else {
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// https://dev.mysql.com/doc/refman/5.7/en/server-status-variables.html
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if ( $s->Innodb_buffer_pool_pages_total > 0 ) {
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$ratio = $s->Innodb_buffer_pool_pages_data / $s->Innodb_buffer_pool_pages_total;
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} else {
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$ratio = 1.0;
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}
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// Stop caring once $ratio >= $this->warmCacheRatio
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$weight *= min( $ratio / $this->warmCacheRatio, 1.0 );
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}
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}
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return $weight;
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}
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}
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