MediaWiki  master
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1 <?php
22 namespace Wikimedia\Rdbms;
35  private $warmCacheRatio;
37  public function __construct(
38  ILoadBalancer $lb, BagOStuff $srvCache, WANObjectCache $wCache, array $options = []
39  ) {
40  parent::__construct( $lb, $srvCache, $wCache, $options );
42  $this->warmCacheRatio = $options['warmCacheRatio'] ?? 0.0;
43  }
45  protected function getWeightScale( $index, IDatabase $conn = null ) {
46  if ( !$conn ) {
47  return parent::getWeightScale( $index, $conn );
48  }
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  //
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  }
69  return $weight;
70  }
71 }
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
float $warmCacheRatio
What buffer pool use ratio counts as "warm" (e.g.
Basic MySQL load monitor with no external dependencies Uses memcached to cache the replication lag fo...
Definition: database.txt:21
Basic DB load monitor with no external dependencies Uses memcached to cache the replication lag for a...
Definition: LoadMonitor.php:36
__construct(ILoadBalancer $lb, BagOStuff $srvCache, WANObjectCache $wCache, array $options=[])
Construct a new LoadMonitor with a given LoadBalancer parent.
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:1982
this hook is for auditing only or null if authentication failed before getting that far or null if we can t even determine that When $user is not null
Definition: hooks.txt:780
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:35
Database cluster connection, tracking, load balancing, and transaction manager interface.
Basic database interface for live and lazy-loaded relation database handles.
Definition: IDatabase.php:38
getWeightScale( $index, IDatabase $conn=null)