6494ea0ba0
All callers are in core and have been updated. Other callers can now be switched from LoadBalancer type hints to ILoadBalancer type hints. Once that migration is done, the classes implementing it can be moved too. Change-Id: I6b34099b5816dd8bf9646ed39f7a2d1960e2ed06
73 lines
2.2 KiB
PHP
73 lines
2.2 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 IDatabase;
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use BagOStuff;
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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, BagOStuff $cache, array $options = []
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) {
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parent::__construct( $lb, $srvCache, $cache, $options );
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$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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