-memcached support for MediaWiki:
-
-From ca August 2003, MediaWiki has optional support for memcached, a
-"high-performance, distributed memory object caching system".
-For general information on it, see: http://www.danga.com/memcached/
+MediaWiki has optional support for memcached, a "high-performance,
+distributed memory object caching system". For general information
+on it, see: http://www.danga.com/memcached/
Memcached is likely more trouble than a small site will need, but
for a larger site with heavy load, like Wikipedia, it should help
lighten the load on the database servers by caching data and objects
in memory.
-== Requirements ==
+== Installation ==
+
+Packages are available for Fedora, Debian, Ubuntu and probably other
+Linux distributions. If you there's no package available for your
+distribution, you can compile it from source.
+
+== Compilation ==
* PHP must be compiled with --enable-sockets
a network; storage can be distributed across multiple servers, and
multiple web servers can use the same cache cluster.
-
********************* W A R N I N G ! ! ! ! ! ***********************
Memcached has no security or authentication. Please ensure that your
server is appropriately firewalled, and that the port(s) used for
memcached servers are not publicly accessible. Otherwise, anyone on
the internet can put data into and read data from your cache.
-An attacker familiar with MediaWiki internals could use this to give
-themselves developer access and delete all data from the wiki's
-database, as well as getting all users' password hashes and e-mail
-addresses.
+An attacker familiar with MediaWiki internals could use this to steal
+passwords and email addresses, or to make themselves a sysop and
+install malicious javascript on the site. There may be other types
+of vulnerability, no audit has been done -- so be safe and keep it
+behind a firewall.
********************* W A R N I N G ! ! ! ! ! ***********************
== Setup ==
-If you want to start small, just run one memcached on your web
-server:
+If you installed memcached using a distro, the daemon should be started
+automatically using /etc/init.d/memcached.
+
+To start the daemon manually, use something like:
- memcached -d -l 127.0.0.1 -p 11000 -m 64
+ memcached -d -l 127.0.0.1 -p 11211 -m 64
(to run in daemon mode, accessible only via loopback interface,
-on port 11000, using up to 64MB of memory)
+on port 11211, using up to 64MB of memory)
In your LocalSettings.php file, set:
- $wgUseMemCached = true;
- $wgMemCachedServers = array( "127.0.0.1:11000" );
+ $wgMainCacheType = CACHE_MEMCACHED;
+ $wgMemCachedServers = array( "127.0.0.1:11211" );
The wiki should then use memcached to cache various data. To use
multiple servers (physically separate boxes or multiple caches
usage evenly), make its entry a subarray:
$wgMemCachedServers = array(
- "127.0.0.1:11000", # one gig on this box
- array("192.168.0.1:11000", 2) # two gigs on the other box
+ "127.0.0.1:11211", # one gig on this box
+ array("192.168.0.1:11211", 2 ) # two gigs on the other box
);
-
== PHP client for memcached ==
-As of this writing, MediaWiki includes version 1.0.10 of the PHP
-memcached client by Ryan Gilfether <hotrodder@rocketmail.com>.
-You'll find some documentation for it in the 'php-memcached'
-subdirectory under the present one.
-
-We intend to track updates, but if you want to check for the lastest
-released version, see http://www.danga.com/memcached/apis.bml
+MediaWiki uses a fork of Ryan T. Dean's pure-PHP memcached client.
+The newer PECL module is not yet supported.
-If you don't set $wgUseMemCached, we still create a MemCacheClient,
+MediaWiki uses three object for object caching:
+* $wgMemc, controlled by $wgMainCacheType
+* $parserMemc, controlled by $wgParserCacheType
+* $messageMemc, controlled by $wgMessageCacheType
+If you set CACHE_NONE to one of the three control variable, (default
+value for $wgMainCacheType), MediaWiki still create a MemCacheClient,
but requests to it are no-ops and we always fall through to the
database. If the cache daemon can't be contacted, it should also
disable itself fairly smoothly.
+By default, $wgMemc is used but when it is $parserMemc or $messageMemc
+this is mentionned below.
+
== Keys used ==
-User:
- key: $wgDBname:user:id:$sId
- ex: wikidb:user:id:51
- stores: instance of class User
- set in: User::loadFromSession()
- cleared by: User::saveSettings(), UserTalkUpdate::doUpdate()
-
+(incomplete, out of date)
+
+Date Formatter:
+ key: $wgDBname:dateformatter
+ ex: wikidb:dateformatter
+ stores: a single instance of the DateFormatter class
+ cleared by: nothing
+ expiry: one hour
+
+Difference Engine:
+ key: $wgDBname:diff:version:{MW_DIFF_VERSION}:oldid:$old:newid:$new
+ ex: wikidb:diff:version:1.11a:oldid:1:newid:2
+ stores: body of a difference
+ cleared by: nothing
+ expiry: one week
+
+Interwiki:
+ key: $wgDBname:interwiki:$prefix
+ ex: wikidb:interwiki:w
+ stores: object from the interwiki table of the database
+ expiry: $wgInterwikiExpiry
+ cleared by: nothing
+
+Lag time of the databases:
+ key: $wgDBname:lag_times
+ ex: wikidb:lag_times
+ stores: array mapping the database id to its lag time
+ expriy: 5 secondes
+ cleared by: nothing
+
+Localisation:
+ key: $wgDBname:localisation:$lang
+ ex: wikidb:localisation:de
+ stores: array of localisation settings
+ set in: Language::loadLocalisation()
+ expiry: none
+ cleared by: Language::loadLocalisation()
+
+Message Cache:
+ stored in: $messageMemc
+ key: $wgDBname:messages, $wgDBname:messages-hash, $wgDBname:messages-status
+ ex: wikidb:messages, wikidb:messages-hash, wikidb:messages-status
+ stores: an array where the keys are DB keys and the values are messages
+ set in: wfMsg(), Article::editUpdates() and Title::moveTo()
+ expriy: $wgMsgCacheExpiry
+ cleared by: nothing
+
Newtalk:
key: $wgDBname:newtalk:ip:$ip
ex: wikidb:newtalk:ip:123.45.67.89
stores: integer, 0 or 1
set in: User::loadFromDatabase()
cleared by: User::saveSettings() # ?
- expiry set to 30 minutes
-
-LinkCache:
- key: $wgDBname:lc:title:$title
- ex: wikidb:lc:title:Wikipedia:Welcome,_Newcomers!
- stores: cur_id of page, or 0 if page does not exist
- set in: LinkCache::addLink()
- cleared by: LinkCache::clearBadLink()
- should be cleared on page deletion and rename
-MediaWiki namespace:
- key: $wgDBname:messages
- ex: wikidb:messages
- stores: an array where the keys are DB keys and the values are messages
- set in: wfMsg(), Article::editUpdates() both call wfLoadAllMessages()
+ expiry: 30 minutes
+
+Parser Cache:
+ stored in: $parserMemc
+ controlled by: $wgEnableParserCache
+ key: $wgDBname:pcache:idhash:$pageid-$renderkey!$hash
+ $pageid: id of the page
+ $renderkey: 1 if action=render, 0 otherwise
+ $hash: hash of user options applied to the page, see ParserOptions::optionsHash()
+ ex: wikidb:pcache:idhash:1-0!1!0!!en!2
+ stores: ParserOutput object
+ modified by: WikiPage::doEditUpdates() or PoolWorkArticleView::doWork()
+ expiry: $wgParserCacheExpireTime or less if it contains short lived functions
+
+ key: $wgDBname:pcache:idoptions:$pageid
+ stores: CacheTime object with an additional list of used options for the hash,
+ serves as ParserCache pointer.
+ modified by: ParserCache::save()
+ expiry: The same as the ParserCache entry it points to.
+
+Ping limiter:
+ controlled by: $wgRateLimits
+ key: $wgDBname:limiter:action:$action:ip:$ip,
+ $wgDBname:limiter:action:$action:user:$id,
+ mediawiki:limiter:action:$action:ip:$ip and
+ mediawiki:limiter:action:$action:subnet:$sub
+ ex: wikidb:limiter:action:edit:ip:123.45.67.89,
+ wikidb:limiter:action:edit:user:1012
+ mediawiki:limiter:action:edit:ip:123.45.67.89 and
+ mediawiki:limiter:action:$action:subnet:123.45.67
+ stores: number of action made by user/ip/subnet
+ cleared by: nothing
+ expiry: expiry set for the action and group in $wgRateLimits
+
+
+Proxy Check: (deprecated)
+ key: $wgDBname:proxy:ip:$ip
+ ex: wikidb:proxy:ip:123.45.67.89
+ stores: 1 if the ip is a proxy
+ cleared by: nothing
+ expiry: $wgProxyMemcExpiry
+
+Revision text:
+ key: $wgDBname:revisiontext:textid:$id
+ ex: wikidb:revisiontext:textid:1012
+ stores: text of a revision
cleared by: nothing
+ expriry: $wgRevisionCacheExpiry
+
+Sessions:
+ controlled by: $wgSessionsInMemcached
+ key: $wgBDname:session:$id
+ ex: wikidb:session:38d7c5b8d3bfc51egf40c69bc40f8be3
+ stores: $SESSION, useful when using a multi-sever wiki
+ expriy: one hour
+ cleared by: session_destroy()
+
+Sidebar:
+ stored in: $parserMemc
+ controlled by: $wgEnableSidebarCache
+ key: $wgDBname:sidebar
+ ex: wikidb:sidebar
+ stores: the html output of the sidebar
+ expriy: $wgSidebarCacheExpiry
+ cleared by: MessageCache::replace()
+
+Special:Allpages:
+ key: $wgDBname:allpages:ns:$ns
+ ex: wikidb:allpages:ns:0
+ stores: array of pages in a namespace
+ expiry: one hour
+ cleared by: nothing
+
+Special:Recentchanges (feed):
+ stored in: $messageMemc
+ key: $wgDBname:rcfeed:$format:$limit:$hideminor:$target and
+ rcfeed:$format:timestamp
+ ex: wikidb:rcfeed:rss:50:: and rcfeed:rss:timestamp
+ stores: xml output of feed
+ expiry: one day
+ clear by: maintenance/rebuildrecentchanges.php script, or
+ calling Special:Recentchanges?action=purge&feed=rss,
+ Special:Recentchanges?action=purge&feed=atom,
+ but note need $wgGroupPermissions[...]['purge'] permission.
+
+Statistics:
+ controlled by: $wgStatsMethod
+ key: $wgDBname:stats:$key
+ ex: wikibd:stats:request_with_session
+ stores: counter for statistics (see maintenance/stats.php script)
+ expiry: none (?)
+ cleared by: maintenance/clear_stats.php script
-Watchlist:
- key: $wgDBname:watchlist:id:$userID
- ex: wikidb:watchlist:id:4635
- stores: HTML string
- cleared by: nothing, expiry time $wgWLCacheTimeout (1 hour)
- note: emergency optimisation only
-
-IP blocks:
- key: $wgDBname:ipblocks
- ex: wikidb:ipblocks
- stores: array of arrays, for the BlockCache class
- cleared by: BlockCache:clear()
+User:
+ key: $wgDBname:user:id:$sId
+ ex: wikidb:user:id:51
+ stores: instance of class User
+ set in: User::saveToCache()
+ cleared by: User::saveSettings(), User::clearSharedCache()
... more to come ...
dépôts / lhc / web / wiklou.git / blobdiff