Wiki source code of Performance

Version 52.3 by Vincent Massol on 2015/04/09

version	line-number	content
22.1	1	{{box cssClass="floatinginfobox" title="Contents"}}
	2	{{toc/}}
	3	{{/box}}
20.1	4
17.1	5	Here are some tips to increase XWiki's performance.
10.1	6
49.1	7	= Clustering =
	8
	9	If you need high availability or if the load on your XWiki instance is too high you can [[configure XWiki in a cluster>>platform:AdminGuide.Clustering]] to spread the load.
	10
48.1	11	= Standalone Solr =
	12
	13	By default XWiki ships with an embedded Solr. If you have a lot of wiki pages (for example in a wiki farm with lots of subwikis), the embedded Solr may use up too much memory and CPU and in this case it's a good idea to externalize Solr on a different server. To do so:
50.1	14
48.1	15	* [[Download and install Solr>>https://cwiki.apache.org/confluence/display/solr/Installing+Solr]]
	16	* [[Configure XWiki to use an external Solr instance>>extensions:Extension.Solr Search API\|\|anchor="HConfiguration"]]
	17
42.1	18	= Slow random number generation on UNIX =
	19
46.1	20	The library used for random number generation in Sun's JVM relies on ##/dev/random## by default for UNIX platforms.
42.1	21
48.3	22	Although ##/dev/random## is more secure, it's possible to use ##/dev/urandom## if the default JVM configuration instead.
42.1	23
	24	To determine if your operating system exhibits this behavior, try displaying a portion of the file from a shell prompt:
	25
45.1	26	{{code language="bash"}}
42.1	27	head -n 1 /dev/random
45.1	28	{{/code}}
42.1	29
46.1	30	If the command returns immediately, you can use ##/dev/random## as the default generator for SUN's JVM. If the command does not return immediately, use these steps to configure the JVM to use ##/dev/urandom##:
42.1	31
44.1	32	1. Open the ##$JAVA_HOME/jre/lib/security/java.security## file in a text editor.
	33	1. Change the line:
50.1	34	{{code language="properties"}} securerandom.source=file:/dev/random{{/code}}
42.1	35	to read:
50.1	36	{{code language="properties"}} securerandom.source=file:/dev/urandom{{/code}}
44.1	37	1. Save your change and exit the text editor.
42.1	38
20.2	39	= Gzip compression and caching of static pages =
14.1	40
20.1	41	We're working on making these features part of the XWiki core (see [[XWIKI-2022>>http://jira.xwiki.org/jira/browse/XWIKI-2022]]). While waiting for this to be natively implemented, the recommended solution is to set up an Apache Web Server in front of your servlet container and install/configure the following modules:
14.1	42
20.1	43	* [[mod-deflate>>http://httpd.apache.org/docs/2.0/mod/mod_deflate.html]]
	44	* [[mod-expire>>http://httpd.apache.org/docs/2.0/mod/mod_expires.html]]
	45	* [[mod-proxy-ajp>>http://httpd.apache.org/docs/2.2/mod/mod_proxy_ajp.html]] (note that this depends on [[mod-proxy>>http://httpd.apache.org/docs/2.2/mod/mod_proxy.html]] that you also need to install)
	46
14.1	47	Modify your Apache configuration file to load the different modules:
	48
20.1	49	{{code language="none"}}
14.1	50	LoadModule expires_module /usr/lib/apache2/modules/mod_expires.so
	51	LoadModule deflate_module /usr/lib/apache2/modules/mod_deflate.so
	52	LoadModule proxy_module /usr/lib/apache2/modules/mod_proxy.so
	53	# Depends: proxy
	54	LoadModule proxy_ajp_module /usr/lib/apache2/modules/mod_proxy_ajp.so
20.1	55	{{/code}}
14.1	56
37.1	57	//Alternatively you can run the following commands as root (sudo)//
	58
	59	{{code language="bash"}}
	60	a2enmod deflate
	61	a2enmod proxy_ajp
	62	a2enmod expires
	63	{{/code}}
	64
32.2	65	and configure your different modules as described below:
14.1	66
20.2	67	== Mod Deflate Configuration ==
14.1	68
20.1	69	{{code language="none"}}
14.1	70	vwwwpro-1:~# cat /etc/apache2/conf.d/deflate
	71	<Location />
	72	# Insert filter
	73	SetOutputFilter DEFLATE
	74
	75	# Netscape 4.x has some problems...
	76	BrowserMatch ^Mozilla/4 gzip-only-text/html
	77
	78	# Netscape 4.06-4.08 have some more problems
20.1	79	BrowserMatch ^Mozilla/4.0[678] no-gzip
14.1	80
	81	# MSIE masquerades as Netscape, but it is fine
20.1	82	# BrowserMatch bMSIE !no-gzip !gzip-only-text/html
14.1	83
	84	# NOTE: Due to a bug in mod_setenvif up to Apache 2.0.48
	85	# the above regex won't work. You can use the following
	86	# workaround to get the desired effect:
20.1	87	BrowserMatch bMSI[E] !no-gzip !gzip-only-text/html
14.1	88
	89	# Don't compress images
20.1	90	SetEnvIfNoCase Request_URI .(?:gif\|jpe?g\|png)$ no-gzip dont-vary
14.1	91
	92	# Make sure proxies don't deliver the wrong content
	93	#Header append Vary User-Agent env=!dont-vary
	94	</Location>
20.1	95	{{/code}}
14.1	96
37.1	97	//On debian apache2 the config file for deflate is located under /etc/apache2/mods-enabled/deflate.conf//
	98
20.2	99	== Mod Expire Configuration ==
14.1	100
20.1	101	{{code language="none"}}
14.1	102	vwwwpro-1:~# cat /etc/apache2/conf.d/expires
	103	<Location /xwiki/skins/>
	104	ExpiresActive on
	105	ExpiresDefault "access plus 1 day"
	106	</Location>
	107
	108	<Location /xwiki/bin/skin/>
	109	ExpiresActive on
	110	ExpiresDefault "access plus 1 day"
	111	</Location>
20.1	112	{{/code}}
14.1	113
20.2	114	== Mod Proxy AJP Configuration ==
14.1	115
20.1	116	{{code language="none"}}
	117	ProxyRequests Off
14.1	118	<Proxy *>
	119	Order deny,allow
	120	Allow from all
	121	</Proxy>
	122	ProxyPreserveHost On
	123	ProxyPass /xwiki ajp://192.168.1.181:8009/xwiki
20.1	124	{{/code}}
14.1	125
20.1	126	where ##ajp:~/~/192.168.1.181:8009/xwiki## is the internal address of your Servlet container where XWiki is running.
14.1	127
37.1	128	If you use Tomcat(7) you need to enable the ajp connector in the /etc/tomcat7/server.xml. Comment out the following line with adding {{code}}<!-- -->{{/code}}. //Maybe give a comment why you did it.//
	129
	130	{{code}}
	131	<!-- disable to use ajp connector instead
	132	<Connector port="8080" protocol="HTTP/1.1"
	133	connectionTimeout="20000"
	134	URIEncoding="UTF-8"
	135	redirectPort="8443" />
	136	-->
	137	{{/code}}
	138
39.1	139	Uncomment the following line by removing the {{code}}<!-- -->{{/code}} and add {{code}}URIEncoding="UTF-8"{{/code}} to it.Maybe give a comment too.
37.1	140
	141	{{code}}
	142	<!-- Activate ajp connector for apache proxy_ajp -->
	143	<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" URIEncoding="UTF-8"/>
	144	{{/code}}
	145
20.2	146	= Memory =
9.1	147
34.1	148	You need to configure your Servlet container so that XWiki has enough memory. You'll need to tune the value to your need. You should check the logs and see if there are any "out of memory" errors. Here are some good default values:
36.1	149
34.1	150	* Small installs: A minimum of 300MB of heap memory and 196MB of permGen (##-Xmx300m -XX:MaxPermSize=196m##)
	151	* Medium installs: 512MB for the heap and 196MB of permGen (##-Xmx512m -XX:MaxPermSize=196m##)
	152	* Large installs: 800MB for the heap and 196MB of permGen (##-Xmx800m -XX:MaxPermSize=196m##). Try not to ge beyond 1024MB since adding more memory means more GC time and thus lower performance.
9.1	153
34.1	154	{{warning}}
	155	Note that storing attachments with the default (in database) storage mechanism is very memory intensive. See the [[administrators guide to attachments>>platform:AdminGuide.Attachments]] for more information about memory cost and the alternative filesystem based attachment store.
38.2	156
	157	Also note that uploading a lot of pages can trigger out of memory (OOM) errors due to scheduled watchlist jobs. For example uploading 1 million pages will trigger OOM errors even when the JVM is configured to run with 2GB of heap space. For such kind of load we recommend to disable (unschedule) the Watchlist jobs (in ##/xwiki/bin/view/Scheduler/##) before uploading the pages.
34.1	158	{{/warning}}
20.1	159
35.1	160	For your information here are the values used for the xwiki.org site:
	161
	162	{{code}}
35.10	163	CATALINA_OPTS="-server -Xms800m -Xmx800m -XX:MaxPermSize=196m -Dfile.encoding=utf-8 -Djava.awt.headless=true -XX:+UseParallelGC -XX:MaxGCPauseMillis=100"
35.1	164	{{/code}}
	165
20.2	166	= Database Indexes =
1.1	167
32.2	168	Make sure you've set [[Database indexes>>Database Administration]]. This is especially important when you start having lots of documents.
1.1	169
20.2	170	= Panels =
1.1	171
32.2	172	Some panels take more resources than others. For example the Navigation panel should NOT be used for wikis with a lot of documents since it displays all documents in the wiki. In the future that panel should be improved for performance but that's not the case right now. Originally this panel was only meant as a starting point. A better approach is to use a "Quick Links Panel" as we've now set up in the default XWiki Enterprise wiki version 1.1 (we've removed the default usage of the Navigation Panel in that version).
1.1	173
20.2	174	= Robots.txt =
15.1	175
32.2	176	If your wiki is open on the Internet, it'll be crawled by search robots (like GoogleBot, etc). They will call all the URLs and especially the ones that are resource hungry like exports (PDF/RTF). You need to protect against this. To do so configure a ##robots.txt## file like this one and put it in your webserver configuration:
15.1	177
20.1	178	{{code language="none"}}
15.1	179	User-agent: *
22.1	180	Disallow: /xwiki/bin/attach/
	181	Disallow: /xwiki/bin/cancel/
	182	Disallow: /xwiki/bin/commentadd/
	183	Disallow: /xwiki/bin/delattachment/
	184	Disallow: /xwiki/bin/delete/
	185	Disallow: /xwiki/bin/dot/
	186	Disallow: /xwiki/bin/download/
	187	Disallow: /xwiki/bin/downloadrev/
15.1	188	Disallow: /xwiki/bin/edit/
22.1	189	Disallow: /xwiki/bin/export/
	190	Disallow: /xwiki/bin/get/
15.1	191	Disallow: /xwiki/bin/inline/
22.1	192	Disallow: /xwiki/bin/lifeblog/
	193	Disallow: /xwiki/bin/login/
	194	Disallow: /xwiki/bin/loginerror/
	195	Disallow: /xwiki/bin/logout/
	196	Disallow: /xwiki/bin/objectremove/
	197	Disallow: /xwiki/bin/pdf/
15.1	198	Disallow: /xwiki/bin/preview/
	199	Disallow: /xwiki/bin/propadd/
	200	Disallow: /xwiki/bin/propdelete/
22.1	201	Disallow: /xwiki/bin/propupdate/
	202	Disallow: /xwiki/bin/register/
	203	Disallow: /xwiki/bin/save/
15.1	204	Disallow: /xwiki/bin/skin/
	205	Disallow: /xwiki/bin/status/
22.1	206	Disallow: /xwiki/bin/upload/
	207	Disallow: /xwiki/bin/viewattachrev/
15.1	208	Disallow: /xwiki/bin/viewrev/
22.1	209	Disallow: /xwiki/bin/xmlrpc/
	210	# It could be also usefull to block certain spaces from crawling,
	211	# especially if this spaces doesn't provide new content
	212	Disallow: /xwiki/bin/view/Main/
	213	Disallow: /xwiki/bin/view/XWiki/
	214	# on the other hand you would like to have your recent (public) changes included
	215	Allow: /xwiki/bin/view/Main/Dashboard
20.1	216	{{/code}}
15.1	217
32.1	218
32.2	219	Note:
32.1	220
32.2	221	For Tomcat6 the placement of the ##robots.txt## file should be within the //$TOMCAT/webapps/ROOT// folder and should have permission 644 applied.
32.1	222
	223	{{code}}
	224	-rw-r--r-- 1 root www 1478 Jan 8 15:52 robots.txt
	225	{{/code}}
	226
32.2	227	In order to test if the ##robots.txt## file is either accessable or working as desired use this [[checker>>http://www.frobee.com/robots-txt-check]].
32.1	228
20.2	229	= Statistics =
1.1	230
20.1	231	{{info}}
	232	This is no longer true starting with XE 1.4M2 since statistics are now put on a queue and written in a different thread in the database in one go, thus reducing the overhead to a maximum.
	233	{{/info}}
15.1	234
32.2	235	The statistics module is off by default since it's quite database intensive. If you don't need it you should turn it off.
1.2	236
20.2	237	= Monitoring =
7.1	238
20.1	239	More a developer-oriented feature, XWiki can monitor its own code, reporting the time spent for each sub-component activated during a request. While the monitoring code isn't time consuming, it increases the memory consumption a bit, and the create/start/stop/log/destroy calls are spread all around the code, so you will save a lot of method calls by disabling this. You can do that by setting the following line in ##xwiki.cfg##:
	240
	241	{{code language="null"}}
19.1	242	xwiki.monitor=0
20.1	243	{{/code}}
7.1	244
52.3	245	= Document Cache =
1.2	246
52.3	247	You can tune the Document cache in the ##xwiki.cfg## configuration file. The value depends on how much memory you have. The higher the better. A good reasonable value is 1000.
2.1	248
20.1	249	{{code language="none"}}
19.1	250	xwiki.store.cache.capacity=1000
20.1	251	{{/code}}
8.1	252
25.1	253	= Cache Macro =
	254
26.1	255	It's possible to perform selective content caching by using the [[Cache Macro>>extensions:Extension.Cache Macro]].
25.1	256
51.1	257	= LESS Cache =
	258
52.2	259	[[LESS>>extensions:Extension.LESS Module]] is a preprocessor used to generate CSS files for skins and skin extensions. See the [[Performance section>>extensions:Extension.LESS Module\|\|anchor="HPerformances"]] of the LESS module documentation to learn more about how to optimize this cache for performances.
51.1	260
20.2	261	= Rendering cache =
2.1	262
30.1	263	Some pages are complex to render (they may aggregate outside data for example or do complex and slow queries). For theses pages you can use rendering cache.
	264
29.1	265	== Configuration based ==
25.1	266
32.2	267	Pages can be cached (i.e. their rendered content cached) to speed up displaying. The configuration is done in ##xwiki.properties## with the following configuration options:
25.1	268
	269	{{code language="none"}}
	270	#-# [Since 2.4M1]
	271	#-# Indicate if the rendering cache is enabled.
	272	#-# Default value is false.
	273	# core.renderingcache.enabled=true
	274
	275	#-# [Since 2.4M1]
	276	#-# A list of Java regex patterns matching full documents reference.
	277	# core.renderingcache.documents=wiki:Space\.Page
	278	# core.renderingcache.documents=wiki:Space\..*
	279
	280	#-# [Since 2.4M1]
	281	#-# The time (in seconds) after which data should be removed from the cache when not used.
	282	#-# Default value is 300 (5 min).
	283	# core.renderingcache.duration=300
	284
	285	#-# [Since 2.4M1]
	286	#-# The size of the rendering cache. Not that it's not the number of cached documents but the number of cached results.
	287	#-# (For a single document several cache entries are created, because each action, language and request query string
	288	#-# produces a unique rendering result)
	289	#-# Default value is 100.
	290	# core.renderingcache.size=100
	291	{{/code}}
	292
31.1	293	You can force a page to refresh using ##refresh=1## in the URL.
30.1	294
41.1	295	Since 6.2 it's also possible to programmatically refresh any document cache using ##com.xpn.xwiki.internal.cache.rendering.RenderingCache## component:
39.1	296
	297	{{code language="java"}}
	298	@Inject
	299	private RenderingCache renderingCache;
	300
	301	...
	302
	303	renderingCache.flushWholeCache();
	304	renderingCache.flushCache(new DocumentReference("xwiki", "MySpace", "MyCachedDocument"));
	305	{{/code}}
	306
28.1	307	== Enabled using velocity in document content itself (XWiki 1.0 syntax only) ==
25.1	308
30.1	309	You can add the following to their content to cache them after they are rendered. Note that the document is refreshed whenever the content of the document changes, and the cache takes into account the URL, so it is pretty safe to add a long cache duration for all documents that don't contain scripts gathering data from the wiki. For example to cache the rendered content for 60 seconds you would add:
2.1	310
20.1	311	{{code language="none"}}
19.1	312	$context.setCacheDuration(60)
20.1	313	{{/code}}
2.1	314
20.1	315	Since 1.5M2, you can set the default rendering cache duration for all pages in ##xwiki.cfg##:
	316
	317	{{code language="none"}}
16.1	318	## cache all rendered documents for one hour
	319	xwiki.rendering.defaultCacheDuration=3600
20.1	320	{{/code}}
	321
16.1	322	Setting the default cache duration to a large value, and manually disabling the cache in dynamic pages would really speed up the wiki, since the rendering is one of the most time consuming processes.
	323
20.2	324	= Merge the CSS files =
11.1	325
32.2	326	In order to reduce the number of requests and files that are downloaded from the browser or client, it could help to merge all XWiki CSS files into a single one. See the [[Merge CSS Script>>extensions:Extension.Merge CSS]].
11.1	327
20.2	328	= Set up NginX =
19.2	329
32.2	330	If you experience //__heavy loads__// on your wiki, you could try using NginX.
19.3	331
36.1	332	NginX is used to fetch static content: images, javascript, styles, etc, but it can also be used as a reverse-proxy to pass requests down to the web container (e.g. Tomcat on port 8080).
19.2	333
32.2	334	Unlike Apache, which instantiates a new process per every static file, NginX uses the same process to fetch all the static data, and thus gives you extra perfomance "for free".
19.2	335
32.2	336	For more info on setting up NginX check [[this guide>>NginX]].
19.2	337
20.2	338	= Backlinks =
4.1	339
20.1	340	While a pretty neat feature, keeping track of the backlinks has a medium impact on the document saving time and a minor impact on the document loading time. If you feel that your wiki does not need backlinks, you can safely disable them with the following line in ##xwiki.cfg##:
	341
	342	{{code language="none"}}
19.1	343	xwiki.backlinks=0
20.1	344	{{/code}}
5.1	345
20.2	346	= Versioning =
5.1	347
32.2	348	One of the key features of any wiki system, versioning greatly affects the database size and the document update time. If you are sure your wiki does not need to keep track of all the changes and you will never need to revert documents to a previous version, then you can add the following line in ##xwiki.cfg##:
20.1	349
	350	{{code language="none"}}
19.1	351	xwiki.store.versioning=0
20.1	352	{{/code}}
6.1	353
21.1	354	= Custom Mapping =
6.1	355
32.2	356	In some cases you may not want to rely on XWiki's generic database schema for storing XClass data and instead you'd like to provide your own optimized table. For these use cases you can use [[Custom Mapping>>platform:DevGuide.CustomMapping]].
21.1	357
	358	= Wiki syntax features for XWiki Syntax 1.0 =
	359
47.1	360	If you're using XWiki Syntax 1.0 and if you don't plan to use all of the markup features, like the strikethrough filter, the automatic http links filter, the SVG, Laszlo or style macros, you can disable them in ##xwiki-core-.jar/META-INF/services/com.xpn.xwiki.render.##. The wiki rendering is the most costly operation in the rendering process, so any disabled feature counts.
	361
	362	Now this will have no effect if you're using another syntax, like XWiki Syntax 2.x.

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