Wiki source code of Performance

Version 85.2 by Vincent Massol on 2017/05/03

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
66.1	13	By default XWiki use an embedded instance of Solr for easy of use but if you find yourself struggling with very slow search you should probably give external Solr instance a try. You can use ##debug=true## in the URL of the search to check how long is taken in Solr itself to know if improving Solr speeed would really change anything (the issue might come from the UI on XWiki side too).
50.1	14
65.1	15	See [[Performance Guide in Solr module documentation>>extensions:Extension.Solr Search API#HPerformances]].
64.1	16
42.1	17	= Slow random number generation on UNIX =
	18
67.1	19	The library used for random number generation in Oracle's JVM relies on ##/dev/random## by default for UNIX platforms.
42.1	20
48.3	21	Although ##/dev/random## is more secure, it's possible to use ##/dev/urandom## if the default JVM configuration instead.
42.1	22
	23	To determine if your operating system exhibits this behavior, try displaying a portion of the file from a shell prompt:
	24
45.1	25	{{code language="bash"}}
42.1	26	head -n 1 /dev/random
45.1	27	{{/code}}
42.1	28
79.1	29	If the command returns immediately, you can use ##/dev/random## as the default generator for Oracle's JVM. If the command does not return immediately, use on of the following solutions to use ##/dev/urandom##:
42.1	30
79.1	31	== JVM setup ==
	32
44.1	33	1. Open the ##$JAVA_HOME/jre/lib/security/java.security## file in a text editor.
	34	1. Change the line:
50.1	35	{{code language="properties"}} securerandom.source=file:/dev/random{{/code}}
42.1	36	to read:
50.1	37	{{code language="properties"}} securerandom.source=file:/dev/urandom{{/code}}
44.1	38	1. Save your change and exit the text editor.
42.1	39
79.1	40	== Command line parameter ==
	41
	42	The same effect can be obtained using ##-Djava.security.egd=file:/dev/urandom## in the Java command line (usually in the application server configuration).
	43
20.2	44	= Gzip compression and caching of static pages =
14.1	45
83.1	46	We're working on making these features part of the XWiki core (see [[XWIKI-2022>>https://jira.xwiki.org/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	47
20.1	48	* [[mod-deflate>>http://httpd.apache.org/docs/2.0/mod/mod_deflate.html]]
81.1	49	* [[mod-expires>>http://httpd.apache.org/docs/2.0/mod/mod_expires.html]]
20.1	50	* [[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)
	51
14.1	52	Modify your Apache configuration file to load the different modules:
	53
20.1	54	{{code language="none"}}
14.1	55	LoadModule expires_module /usr/lib/apache2/modules/mod_expires.so
	56	LoadModule deflate_module /usr/lib/apache2/modules/mod_deflate.so
	57	LoadModule proxy_module /usr/lib/apache2/modules/mod_proxy.so
	58	# Depends: proxy
	59	LoadModule proxy_ajp_module /usr/lib/apache2/modules/mod_proxy_ajp.so
20.1	60	{{/code}}
14.1	61
37.1	62	//Alternatively you can run the following commands as root (sudo)//
	63
	64	{{code language="bash"}}
	65	a2enmod deflate
	66	a2enmod proxy_ajp
	67	a2enmod expires
	68	{{/code}}
	69
32.2	70	and configure your different modules as described below:
14.1	71
20.2	72	== Mod Deflate Configuration ==
14.1	73
20.1	74	{{code language="none"}}
14.1	75	vwwwpro-1:~# cat /etc/apache2/conf.d/deflate
	76	<Location />
	77	# Insert filter
	78	SetOutputFilter DEFLATE
	79
	80	# Netscape 4.x has some problems...
	81	BrowserMatch ^Mozilla/4 gzip-only-text/html
	82
	83	# Netscape 4.06-4.08 have some more problems
20.1	84	BrowserMatch ^Mozilla/4.0[678] no-gzip
14.1	85
	86	# MSIE masquerades as Netscape, but it is fine
20.1	87	# BrowserMatch bMSIE !no-gzip !gzip-only-text/html
14.1	88
	89	# NOTE: Due to a bug in mod_setenvif up to Apache 2.0.48
	90	# the above regex won't work. You can use the following
	91	# workaround to get the desired effect:
20.1	92	BrowserMatch bMSI[E] !no-gzip !gzip-only-text/html
14.1	93
	94	# Don't compress images
20.1	95	SetEnvIfNoCase Request_URI .(?:gif\|jpe?g\|png)$ no-gzip dont-vary
14.1	96
	97	# Make sure proxies don't deliver the wrong content
	98	#Header append Vary User-Agent env=!dont-vary
	99	</Location>
20.1	100	{{/code}}
14.1	101
37.1	102	//On debian apache2 the config file for deflate is located under /etc/apache2/mods-enabled/deflate.conf//
	103
20.2	104	== Mod Expire Configuration ==
14.1	105
20.1	106	{{code language="none"}}
14.1	107	vwwwpro-1:~# cat /etc/apache2/conf.d/expires
	108	<Location /xwiki/skins/>
	109	ExpiresActive on
	110	ExpiresDefault "access plus 1 day"
	111	</Location>
	112
	113	<Location /xwiki/bin/skin/>
	114	ExpiresActive on
	115	ExpiresDefault "access plus 1 day"
	116	</Location>
20.1	117	{{/code}}
14.1	118
20.2	119	== Mod Proxy AJP Configuration ==
14.1	120
20.1	121	{{code language="none"}}
	122	ProxyRequests Off
14.1	123	<Proxy *>
	124	Order deny,allow
	125	Allow from all
	126	</Proxy>
	127	ProxyPreserveHost On
	128	ProxyPass /xwiki ajp://192.168.1.181:8009/xwiki
20.1	129	{{/code}}
14.1	130
20.1	131	where ##ajp:~/~/192.168.1.181:8009/xwiki## is the internal address of your Servlet container where XWiki is running.
14.1	132
37.1	133	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.//
	134
	135	{{code}}
	136	<!-- disable to use ajp connector instead
	137	<Connector port="8080" protocol="HTTP/1.1"
	138	connectionTimeout="20000"
	139	URIEncoding="UTF-8"
	140	redirectPort="8443" />
	141	-->
	142	{{/code}}
	143
39.1	144	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	145
	146	{{code}}
	147	<!-- Activate ajp connector for apache proxy_ajp -->
	148	<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" URIEncoding="UTF-8"/>
	149	{{/code}}
	150
20.2	151	= Memory =
9.1	152
34.1	153	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	154
78.1	155	* For Java 8 (i.e. XWiki >= 8.1). Notice that there's no permgen anymore in Java 8:
79.1	156	** Small and medium installs: A minimum of 1024MB (##-Xmx1024m)##
	157	** Large installs: 2048MB or beyond (##-Xmx2048m).##
78.1	158	* For Java 7 (i.e. XWiki < 8.1)
	159	** Small installs: A minimum of 512MB of heap memory and 196MB of permGen (##-Xmx512m -XX:MaxPermSize=196m##)
	160	** Medium installs: 1024MB for the heap and 196MB of permGen (##-Xmx1024m -XX:MaxPermSize=196m##)
	161	** Large installs: 2048MB (or beyond) for the heap and 196MB of permGen (##-Xmx2048m -XX:MaxPermSize=196m##).
9.1	162
53.3	163	{{info}}
53.1	164	You should not increase the memory beyond what you need because increasing it means that there's more Objects in memory at any time and the automatic JVM Garbage Collector has to work harder to clean itself, which can results in performance degradation in XWiki (since a full GC will pause the application for a longer time).
53.3	165	{{/info}}
53.1	166
34.1	167	{{warning}}
	168	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	169
82.1	170	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. To track the progress on this issue, please see [[XWIKI-10594>>https://jira.xwiki.org/browse/XWIKI-10594]].
34.1	171	{{/warning}}
20.1	172
76.1	173	{{warning}}
	174	If you use HSQLDB as the wiki database, be aware that the full content of the database is stored in memory and thus the memory requirements are higher. See [[HSQLDB installation page>>AdminGuide.InstallationHSQL]] for more details.
	175	{{/warning}}
	176
35.1	177	For your information here are the values used for the xwiki.org site:
	178
	179	{{code}}
53.2	180	CATALINA_OPTS="-server -Xms800m -Xmx1480m -XX:MaxPermSize=222m -Dfile.encoding=utf-8 -Djava.awt.headless=true -XX:+UseParallelGC -XX:MaxGCPauseMillis=100"
35.1	181	{{/code}}
	182
20.2	183	= Database Indexes =
1.1	184
32.2	185	Make sure you've set [[Database indexes>>Database Administration]]. This is especially important when you start having lots of documents.
1.1	186
74.1	187	= Large number of users =
	188
	189	When you have large number of users it's recommended to turn on implicit All Group, i.e. to consider that all users are members of XWiki.XWikiAllGroup by default in the configuration. This is achieved by editing the ##xwiki.cfg## file and setting:
	190
	191	{{code language="none"}}
	192	xwiki.authentication.group.allgroupimplicit=1
	193	{{/code}}
	194
75.1	195	Then you should remove all the XObjects from the XWikiAllGroup page but you should keep the page since otherwise you won't be able to set permissions for this group. This will prevent XWiki from having to load all that page's XObjects representing the users (thousands of them if you have thousands of users).
74.1	196
75.2	197	Also make sure that the ##XWikiAllGroup## is listed in the ##xwiki.users.initialGroups## property (it's there by default if you haven't touched that property):
	198
	199	{{code language="none"}}
	200	#-# List of groups that a new user should be added to by default after registering. Comma-separated list of group
	201	#-# document names.
	202	# xwiki.users.initialGroups=XWiki.XWikiAllGroup
	203	{{/code}}
	204
20.2	205	= Panels =
1.1	206
32.2	207	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	208
20.2	209	= Robots.txt =
15.1	210
85.1	211	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 and put it in your webserver configuration:
15.1	212
85.1	213	Some example:
	214
20.1	215	{{code language="none"}}
15.1	216	User-agent: *
85.2	217	# Prevent bots from exporting since that would be CPU and memory consuming
22.1	218	Disallow: /xwiki/bin/export/
85.2	219	# Prevent bots from downloading attachments since that would be CPU and memory consuming
	220	Disallow: /xwiki/bin/download/
85.1	221	# It could be also useful to block certain spaces from crawling,
22.1	222	# especially if this spaces doesn't provide new content
	223	Disallow: /xwiki/bin/view/Main/
	224	Disallow: /xwiki/bin/view/XWiki/
85.1	225	# On the other hand you would like to have your recent (public) changes included
22.1	226	Allow: /xwiki/bin/view/Main/Dashboard
20.1	227	{{/code}}
15.1	228
32.2	229	Note:
32.1	230
32.2	231	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	232
	233	{{code}}
	234	-rw-r--r-- 1 root www 1478 Jan 8 15:52 robots.txt
	235	{{/code}}
	236
32.2	237	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	238
20.2	239	= Statistics =
1.1	240
20.1	241	{{info}}
	242	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.
	243	{{/info}}
15.1	244
32.2	245	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	246
52.3	247	= Document Cache =
1.2	248
52.3	249	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	250
20.1	251	{{code language="none"}}
19.1	252	xwiki.store.cache.capacity=1000
20.1	253	{{/code}}
8.1	254
25.1	255	= Cache Macro =
	256
26.1	257	It's possible to perform selective content caching by using the [[Cache Macro>>extensions:Extension.Cache Macro]].
25.1	258
77.1	259	= LESS CSS Performances =
51.1	260
77.1	261	[[LESS>>extensions:Extension.LESS Module]] is a preprocessor used to generate CSS files for skins and skin extensions. See the [[Performances section>>extensions:Extension.LESS Module#HPerformances]] of the LESS module documentation to learn more about how to optimize its cache for performances, and to set the appropriate number of simultaneous compilations your server can handle.
51.1	262
20.2	263	= Rendering cache =
2.1	264
30.1	265	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.
	266
29.1	267	== Configuration based ==
25.1	268
32.2	269	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	270
	271	{{code language="none"}}
	272	#-# [Since 2.4M1]
	273	#-# Indicate if the rendering cache is enabled.
	274	#-# Default value is false.
	275	# core.renderingcache.enabled=true
	276
	277	#-# [Since 2.4M1]
	278	#-# A list of Java regex patterns matching full documents reference.
	279	# core.renderingcache.documents=wiki:Space\.Page
	280	# core.renderingcache.documents=wiki:Space\..*
	281
	282	#-# [Since 2.4M1]
	283	#-# The time (in seconds) after which data should be removed from the cache when not used.
	284	#-# Default value is 300 (5 min).
	285	# core.renderingcache.duration=300
	286
	287	#-# [Since 2.4M1]
	288	#-# The size of the rendering cache. Not that it's not the number of cached documents but the number of cached results.
	289	#-# (For a single document several cache entries are created, because each action, language and request query string
	290	#-# produces a unique rendering result)
	291	#-# Default value is 100.
	292	# core.renderingcache.size=100
	293	{{/code}}
	294
31.1	295	You can force a page to refresh using ##refresh=1## in the URL.
30.1	296
41.1	297	Since 6.2 it's also possible to programmatically refresh any document cache using ##com.xpn.xwiki.internal.cache.rendering.RenderingCache## component:
39.1	298
	299	{{code language="java"}}
	300	@Inject
	301	private RenderingCache renderingCache;
	302
	303	...
	304
	305	renderingCache.flushWholeCache();
	306	renderingCache.flushCache(new DocumentReference("xwiki", "MySpace", "MyCachedDocument"));
	307	{{/code}}
	308
25.1	309
20.2	310	= Merge the CSS files =
11.1	311
32.2	312	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	313
20.2	314	= Set up NginX =
19.2	315
32.2	316	If you experience //__heavy loads__// on your wiki, you could try using NginX.
19.3	317
36.1	318	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	319
32.2	320	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	321
32.2	322	For more info on setting up NginX check [[this guide>>NginX]].
19.2	323
20.2	324	= Backlinks =
4.1	325
20.1	326	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##:
	327
	328	{{code language="none"}}
19.1	329	xwiki.backlinks=0
20.1	330	{{/code}}
5.1	331
20.2	332	= Versioning =
5.1	333
32.2	334	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	335
	336	{{code language="none"}}
19.1	337	xwiki.store.versioning=0
20.1	338	{{/code}}
6.1	339
21.1	340	= Custom Mapping =
6.1	341
32.2	342	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	343
73.1	344	= LDAP =
	345
	346	== Disable LDAP sub groups search ==
	347
	348	By default when loading a LDAP group, each member is searched and loaded to figure out if it's a group or not (and then load the sub group members, etc). Since 7.2 If you know there is not sub group in your LDAP groups you can disable it and speed up quite a lot big groups handling using ##xwiki.authentication.ldap.group_sync_resolve_subgroups## property in ##xwiki.cfg## configuration file.
	349
56.1	350	= Performance tree =
	351
57.1	352	Since 7.1 it's possible to directly get a tree of time spent in each step of the request by using [[debug mode>>dev:Community.Debugging#HDebugmode]].
68.1	353
	354	= Legacy =
	355
71.1	356	== Monitor plugin ==
70.1	357
	358	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##:
	359
	360	{{code language="properties"}}
	361	xwiki.monitor=0
	362	{{/code}}
	363
68.1	364	== 1.0 rendering cache using velocity in document content itself ==
	365
	366	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:
	367
	368	{{code language="none"}}
	369	$context.setCacheDuration(60)
	370	{{/code}}
	371
	372	Since 1.5M2, you can set the default rendering cache duration for all pages in ##xwiki.cfg##:
	373
	374	{{code language="none"}}
	375	## cache all rendered documents for one hour
	376	xwiki.rendering.defaultCacheDuration=3600
	377	{{/code}}
	378
	379	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.
69.1	380
72.1	381	== Wiki syntax features for XWiki Syntax 1.0 ==
69.1	382
	383	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.
	384
	385	Now this will have no effect if you're using another syntax, like XWiki Syntax 2.x.

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