Manual talk:$wgParserCacheType

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The suggested text below is based on comments on the mailing list by Platonides and Benjamin Lees. Please correct language and any misunderstandings:

Details
Parser cache setting. Rendering the wikitext is very intensive, thus it should be cached.

The parser cache may speed up pages for onlogged users, while file cache (see $wgUseFileCache) may speed up pages for anonymous users. You may want to enable both.

Here are the available CACHE constants, as defined in Defines.php


 * CACHE_ANYTHING - Use anything, as long as it works
 * CACHE_NONE - Do not cache
 * CACHE_DB - Store cache objects in the DB
 * CACHE_MEMCACHED - memcached, must specify servers in $wgMemCachedServers
 * CACHE_ACCEL - eAccelerator, mmTurck or APC, whichever is available
 * CACHE_DBA - Use PHP's DBA extension to store in a DBM-style database

Usage
Select a constant in the following priority order depending on your machine configuration (starting from bigger machines down to smaller):


 * CACHE_MEMCACHED - ''first choice - given lots of available memory.
 * CACHE_ACCEL - ''second best choice - if accelerators are available.
 * CACHE_DB - ''uses the database, thus performs worse than cache accelerators. May also produce db deadlocks.

For a small setup with limited RAM (say 2GB) using file caching ($wgUseFileCache) is even faster than Memcached / eAccelerator (~ 5 times faster), but the file cache only works for anonymous users and thus one will still need the other cache types ($wgParserCacheType and $wgMainCacheType).

The average benefit of file cache probably depends on whether the page hits are focused on a few articles (good) or roughly evenly distributed over many hundred thousand pages (which would give a not so good result).