Functions to get cache objects. More...

Collaboration diagram for ObjectCache:

[legend]

Static Public Member Functions
static	clear ()
	Clear all the cached instances.

static	detectLocalServerCache ()
	Detects which local server cache library is present and returns a configuration for it.

static	getInstance ( $id)
	Get a cached instance of the specified type of cache object.

static	getLocalClusterInstance ()
	Get the main cluster-local cache object.

static	getLocalServerInstance ( $fallback=CACHE_NONE)
	Factory function for CACHE_ACCEL (referenced from DefaultSettings.php)

static	makeLocalServerCache ()
	Create a new BagOStuff instance for local-server caching.

static	newAnything ( $params)
	Factory function for CACHE_ANYTHING (referenced from DefaultSettings.php)

static	newFromParams (array $params, Config $conf=null)
	Create a new cache object from parameters.

Static Public Attributes
static BagOStuff[]	$instances = []
	Map of (id => BagOStuff)

Static Private Member Functions
static	getDefaultKeyspace ()
	Get the default keyspace for this wiki.

static	newFromId ( $id)
	Create a new cache object of the specified type.

Detailed Description

Functions to get cache objects.

The word "cache" has two main dictionary meanings, and both are used in this factory class. They are:

a) Cache (the computer science definition). A place to store copies or computations on existing data for higher access speeds.
b) Storage. A place to store lightweight data that is not canonically stored anywhere else (e.g. a "hoard" of objects).

The former should always use strongly consistent stores, so callers don't have to deal with stale reads. The latter may be eventually consistent, but callers can use BagOStuff:READ_LATEST to see the latest available data.

Primary entry points:

ObjectCache::getLocalServerInstance( $fallbackType ) Purpose: Memory cache for very hot keys. Stored only on the individual web server (typically APC or APCu for web requests, and EmptyBagOStuff in CLI mode). Not replicated to the other servers.
ObjectCache::getLocalClusterInstance() Purpose: Memory storage for per-cluster coordination and tracking. A typical use case would be a rate limit counter or cache regeneration mutex. Stored centrally within the local data-center. Not replicated to other DCs. Configured by $wgMainCacheType.
ObjectCache::getInstance( $cacheType ) Purpose: Special cases (like tiered memory/disk caches). Get a specific cache type by key in $wgObjectCaches.

All the above BagOStuff cache instances have their makeKey() method scoped to the current wiki ID. Use makeGlobalKey() to avoid this scoping when using keys that need to be shared amongst wikis.

Definition at line 68 of file ObjectCache.php.

Member Function Documentation

◆ clear()

static ObjectCache::clear ( )

static

Clear all the cached instances.

Definition at line 281 of file ObjectCache.php.

◆ detectLocalServerCache()

static ObjectCache::detectLocalServerCache ( )

static

Detects which local server cache library is present and returns a configuration for it.

Since: 1.32

Deprecated:: since 1.35 Use MediaWikiServices::getLocalServerObjectCache() or ObjectCache::makeLocalServerCache() instead.

Returns: int|string Index to cache in $wgObjectCaches

Definition at line 325 of file ObjectCache.php.

References CACHE_NONE, and wfDeprecated().

◆ getDefaultKeyspace()

static ObjectCache::getDefaultKeyspace ( )

staticprivate

Get the default keyspace for this wiki.

This is either the value of the CachePrefix configuration variable, or (if the former is unset) the DBname configuration variable, with DBprefix (if defined).

Returns: string

Definition at line 120 of file ObjectCache.php.

References $wgCachePrefix.

Referenced by makeLocalServerCache().

◆ getInstance()

static ObjectCache::getInstance ( $id )

static

Get a cached instance of the specified type of cache object.

Parameters

string | int $id A key in $wgObjectCaches.

Returns: BagOStuff

Definition at line 78 of file ObjectCache.php.

◆ getLocalClusterInstance()

static ObjectCache::getLocalClusterInstance ( )

static

Get the main cluster-local cache object.

Since: 1.27

Returns: BagOStuff

Definition at line 272 of file ObjectCache.php.

References $wgMainCacheType.

◆ getLocalServerInstance()

static ObjectCache::getLocalServerInstance ( $fallback = CACHE_NONE )

static

Factory function for CACHE_ACCEL (referenced from DefaultSettings.php)

This will look for any APC or APCu style server-local cache. A fallback cache can be specified if none is found.

// Direct calls
ObjectCache::getLocalServerInstance( $fallbackType );

// From $wgObjectCaches via newFromParams()
ObjectCache::getLocalServerInstance( [ 'fallback' => $fallbackType ] );

Parameters

int | string | array $fallback Fallback cache or parameter map with 'fallback'

Returns: BagOStuff

Exceptions

InvalidArgumentException

Since: 1.27

Definition at line 254 of file ObjectCache.php.

References $cache, $fallback, and CACHE_NONE.

◆ makeLocalServerCache()

static ObjectCache::makeLocalServerCache ( )

static

Create a new BagOStuff instance for local-server caching.

Only use this if you explicitly require the creation of a fresh instance. Whenever possible, use or inject the object from MediaWikiServices::getLocalServerObjectCache() instead.

NOTE: This method is called very early via Setup.php by ExtensionRegistry, and thus must remain fairly standalone so as to not cause initialization of the MediaWikiServices singleton.

Since: 1.35

Returns: BagOStuff

Definition at line 299 of file ObjectCache.php.

References getDefaultKeyspace().

◆ newAnything()

static ObjectCache::newAnything ( $params )

static

Factory function for CACHE_ANYTHING (referenced from DefaultSettings.php)

CACHE_ANYTHING means that stuff has to be cached, not caching is not an option. If a caching method is configured for any of the main caches ($wgMainCacheType, $wgMessageCacheType, $wgParserCacheType), then CACHE_ANYTHING will effectively be an alias to the configured cache choice for that. If no cache choice is configured (by default $wgMainCacheType is CACHE_NONE), then CACHE_ANYTHING will forward to CACHE_DB.

Parameters

array $params

Returns: BagOStuff

Definition at line 212 of file ObjectCache.php.

References $cache, $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType, CACHE_ANYTHING, CACHE_DB, and CACHE_NONE.

◆ newFromId()

static ObjectCache::newFromId ( $id )

staticprivate

Create a new cache object of the specified type.

Parameters

string | int $id A key in $wgObjectCaches.

Returns: BagOStuff

Exceptions

InvalidArgumentException

Definition at line 93 of file ObjectCache.php.

References $wgObjectCaches, and CACHE_NONE.

◆ newFromParams()

static ObjectCache::newFromParams	(	array	$params,
		Config	$conf = `null`
	)

static

Create a new cache object from parameters.

Parameters

array	$params	Must have 'factory' or 'class' property. factory: Callback passed $params that returns BagOStuff. class: BagOStuff subclass constructed with $params. loggroup: Alias to set 'logger' key with LoggerFactory group. .. Other parameters passed to factory or class.
Config \| null	$conf	(Since 1.35)

Returns: BagOStuff

Exceptions

InvalidArgumentException

Definition at line 143 of file ObjectCache.php.

Member Data Documentation

◆ $instances

BagOStuff [] ObjectCache::$instances = []

static

Map of (id => BagOStuff)

Definition at line 70 of file ObjectCache.php.

The documentation for this class was generated from the following file:

includes/objectcache/ObjectCache.php

Static Public Member Functions

Static Public Attributes

Static Private Member Functions

Detailed Description

Member Function Documentation

◆ clear()

◆ detectLocalServerCache()

◆ getDefaultKeyspace()

◆ getInstance()

◆ getLocalClusterInstance()

◆ getLocalServerInstance()

◆ makeLocalServerCache()

◆ newAnything()

◆ newFromId()

◆ newFromParams()

Member Data Documentation

◆ $instances