MediaWiki REL1_33
LoadMonitorMySQL.php
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1<?php
22namespace Wikimedia\Rdbms;
23
26
36
37 public function __construct(
39 ) {
40 parent::__construct( $lb, $srvCache, $wCache, $options );
41
42 $this->warmCacheRatio = $options['warmCacheRatio'] ?? 0.0;
43 }
44
45 protected function getWeightScale( $index, IDatabase $conn = null ) {
46 if ( !$conn ) {
47 return parent::getWeightScale( $index, $conn );
48 }
49
50 $weight = 1.0;
51 if ( $this->warmCacheRatio > 0 ) {
52 $res = $conn->query( 'SHOW STATUS', __METHOD__ );
53 $s = $res ? $conn->fetchObject( $res ) : false;
54 if ( $s === false ) {
55 $host = $this->parent->getServerName( $index );
56 $this->replLogger->error( __METHOD__ . ": could not get status for $host" );
57 } else {
58 // https://dev.mysql.com/doc/refman/5.7/en/server-status-variables.html
59 if ( $s->Innodb_buffer_pool_pages_total > 0 ) {
60 $ratio = $s->Innodb_buffer_pool_pages_data / $s->Innodb_buffer_pool_pages_total;
61 } else {
62 $ratio = 1.0;
63 }
64 // Stop caring once $ratio >= $this->warmCacheRatio
65 $weight *= min( $ratio / $this->warmCacheRatio, 1.0 );
66 }
67 }
68
69 return $weight;
70 }
71}
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
Class representing a cache/ephemeral data store.
Definition BagOStuff.php:58
Multi-datacenter aware caching interface.
Basic MySQL load monitor with no external dependencies Uses memcached to cache the replication lag fo...
__construct(ILoadBalancer $lb, BagOStuff $srvCache, WANObjectCache $wCache, array $options=[])
float $warmCacheRatio
What buffer pool use ratio counts as "warm" (e.g.
getWeightScale( $index, IDatabase $conn=null)
Basic DB load monitor with no external dependencies Uses memcached to cache the replication lag for a...
$res
Definition database.txt:21
null means default in associative array with keys and values unescaped Should be merged with default with a value of false meaning to suppress the attribute in associative array with keys and values unescaped & $options
Definition hooks.txt:1999
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition injection.txt:37
Basic database interface for live and lazy-loaded relation database handles.
Definition IDatabase.php:38
Database cluster connection, tracking, load balancing, and transaction manager interface.
The wiki should then use memcached to cache various data To use multiple just add more items to the array To increase the weight of a make its entry a array("192.168.0.1:11211", 2))