$smwgQueryResultCacheType

Configuration parameter details:
Name	$smwgQueryResultCacheType
Description	Sets whether the query result cache may be used
Default setting	CACHE_NONE
Software	Semantic MediaWiki
Since version	2.5.0
Until version	still available
Configuration	Cache · Experimental
Keyword	caching · object cache · performance · query performance · query result cache · experimental

$smwgQueryResultCacheType is a configuration parameter that sets whether the query result cache feature may be used. It was introduced in Semantic MediaWiki 2.5.0Released on 14 March 2017 and compatible with MW 1.23.0 - 1.29.x..1

Using the feature connected to this configuration parameter is considered experimental!

Default setting

$smwgQueryResultCacheType = CACHE_NONE;

This means that by default the query result cache feature is disabled.

Available cache providers

All predefined cache types as provided by configuration parameter $wgMainCacheType (MediaWiki.org) or a custom cache type as set with configuration parameter $wgObjectCaches (MediaWiki.org), e.g. Redis which is the recommended cache provider2 to account for an optimal response time, storage capacity, and independence from the DB master.

• CACHE_NONE: Does not caching (predefined)
• CACHE_ANYTHING: Allows to use whatever cache provider is available (predefined)
• CACHE_ACCEL: Allows to use "APC" as cache provider (predefined)
• CACHE_MEMCACHED: Allows to use "memcached" as cache provider (predefined, requires additional setup on the server)
• CACHE_DB: Allows to use the relational database backend as cache provider (predefined)
• redis: Allows to use "Redis" as cache provider (custom, requires additional setup on the server)

Changing the default setting

When enabling this feature by adding a cache provider to this setting, it is recommended to also enable the embedded query update feature.

This feature can be enabled by adding a cache type as the setting to this configuration parameter, either a predefined cache type or a custom cache type. The wiki will then try to minimize the computational effort for queries that share the same query signature.

To modify the setting to this configuration parameter, add one of the following lines to your "LocalSettings.php" file after the enableSemantics() call:

Use whatever cache provider is available

$smwgQueryResultCacheType = CACHE_ANYTHING;

  Note: Use this setting if unsure which cache provider is available and should be used.

Use "memcached" as cache provider

$smwgQueryResultCacheType = CACHE_MEMCACHED;

  Note: Additional setup on the wiki's server is required to be able to used this cache provider.

Use "redis" as cache provider

$smwgQueryResultCacheType = 'redis';

  Note: 

• Additional setup on the wiki's server as well as further configuration in "LocalSettings.php" is required to be able to used this cache provider.

This is the recommended cache provider.

See also

Caching in general

• Help page on caching
• Help page on configuration parameter $wgMainCacheType (MediaWiki.org)
• Help page on configuration parameter $smwgMainCacheTypeSets which object cache Semantic MediaWiki should use to track temporary changes

Query result caching

• Help page on the query result cache
• Help page on configuration parameter $smwgQueryResultCacheLifetimeSets the cache lifetime of embedded queries and their results fetched from the query engine
• Help page on configuration parameter $smwgQueryResultNonEmbeddedCacheLifetimeSets the cache lifetime of non-embedded queries and their results fetched from the query engine
• Help page on configuration parameter $smwgQueryResultCacheRefreshOnPurgeSets whether it is possible to manually refresh the query cache by doing a "purge" action

Embedded query updating

• Help page on embedded query updates
• Help page on configuration parameter $smwgEnabledQueryDependencyLinksStoreSets whether tracking and storing of dependencies of embedded queries may be used

Other

• Help page on speeding up Semantic MediaWiki
• Help page on configuration parameter $smwgValueLookupCacheTypeSets a separate cache type for the object cache when requesting value lookups from the database