Changes: Help:Purge

Revision as of 08:38, 17 May 2020

The purge function is a handy way to clear a page's server cache. This forces the wiki software to rebuild the page completely.

For example, some pages often use templates, and edits to those templates may not always update immediately on articles. If you can't see the changes properly, purging the page can help. It is also recommended to fully refresh your browser cache as that can also help.

How to purge

Note: purging is usually very quick, but can potentially take a few minutes if the servers are very busy.

An example of a URL showing the purge command.

On any Fandom article page:

At the end of the URL, add the text
?action=purge
Visit that link; the page should be refreshed in a short time

Note, if the URL includes an #anchor, make sure to add the purge code before that part.

Alternatively, you can make a null edit by going into edit mode for the page and saving without making any changes.

How it works

When a change is made to a page, the MediaWiki software saves the change to the main database. The next time a non-logged in user views the page, a copy of that page is made to a "server cache" on a set of secondary servers. Until the page is changed again, all non-logged in users who try to view that page will be shown the same copy from the server cache. That way, users who are viewing but not editing do not put a drain on the main database server, and still see the most recent version of the page.

Normally, when a change is made, the page is marked as "touched" and the software will create a new copy of the page for the server cache. However, when a change is made to a subpage or template, but not to the article page which transcludes it, the article page is not marked as "touched," and a new copy is not immediately generated for the cache. Therefore anyone viewing the article page may see a cached page which includes old versions of the subpage or template.

The purge command forces the server cache to purge the old version of the page. The next time the page is viewed, the page will be rebuilt from scratch, including fresh versions of all subpages and templates, and a new copy will be made for the server cache.

Note that this may take a few minutes in extreme cases. Given that it causes the servers more work, please avoid overusing the purge command.

@@ Line 1: / Line 1: @@
-The '''purge''' function is a handy way to clear a page's server [[Help:Bypass_your_cache|cache]]. This forces the wiki software to rebuild the page completely.
+{{tocright}}The '''purge''' function is a handy way to clear a page's server [[Help:Bypass your cache|cache]]. This forces the wiki software to rebuild the page completely.
-Some pages use [[Help:Templates|transclusion]] to incorporate subpages or templates. If you can't see the transcluded pages properly, purging might help.
+For example, some pages often use [[Help:Templates|templates]], and edits to those templates may not always update immediately on articles. If you can't see the changes properly, purging the page can help. It is also recommended to [[Help:Bypass your cache|fully refresh your browser cache]] as that can also help.
-You may want to try first to [[Help:Bypass your cache|refresh the page]] using your web browser.
 == How to purge ==
-: ''Note: purging may take a few minutes, though it usually happens immediately.''
+: ''Note: purging is usually very quick, but can potentially take a few minutes if the servers are very busy.''
+[[File:Purgeexample.png|thumb|right|300px|An example of a URL showing the purge command.]]
-There are two ways to purge your cache:
+On any Fandom article page:
-[[File:Purgeexample.png|thumb|right|250px|An example of a URL with the purge action.]]
+# At the end of the URL, add the text<br /><code>?action=purge</code>
-From any Wikia page:
+# Visit that link; the page should be refreshed in a short time
-:# At the end of the URL in the address bar of your browser, add the text <tt>?action=purge</tt>
-:# Press [Enter] or click "Go" to tell the browser to go to that revised URL
-:# The page should be refreshed in a short time
+Note, if the URL includes an <code>#anchor</code>, make sure to add the purge code before that part.
-Similarly, from any Wikia page:
-:#Click the "edit this page" tab
-:#In the address bar in your browser, at the end of the URL, where you see ?<tt>action=edit</tt>, replace "edit" with "purge," so it now reads ?<tt>action=purge</tt>
-:# Press [Enter] or click "Go" to tell the browser to go to that revised URL
-:#The page should be refreshed in a short time
-<!--
-commenting out until we have a purge template
+Alternatively, you can make a [[Help:Glossary#Null edit|null edit]] by going into edit mode for the page and saving without making any changes.
-A third way is to use a purge template which creates a clickable link:
-:# Go to the Sandbox
-:# Edit the page and add <nowiki>{{purge}}</nowiki> or <nowiki>{{purge|Purge this page's server cache}}</nowiki>
-:# Save the page
-:# Click on the link it creates (you'll see a blue link called "purge")
--->
-{{Notice
-|border=orange
-|image=[[File:Bulb.png]]
-|style=width: 100%;
-|type=Purge from the Edit menu
-|info=There's a nifty script at the Developer Wiki that adds a {{#NewWindowLink:w:c:dev:PurgeButton|<span style="color:blue;">PurgeButton</span>}} to your pages.<br >Clicking on the {{#NewWindowLink:w:c:dev:DisplayClock|<span style="color:blue;">DisplayClock</span>}} also purges the page. That spares you the URL hacking.
-}}
 ==How it works==
 When a change is made to a page, the MediaWiki software saves the change to the main database. The next time a non-logged in user views the page, a copy of that page is made to a "server cache" on a set of secondary servers. Until the page is changed again, ''all'' non-logged in users who try to view that page will be shown the same copy from the server cache. That way, users who are viewing but not editing do not put a drain on the main database server, and still see the most recent version of the page.
-Normally, when a change is made, the page is marked as "touched" and the software will create a new copy of the page for the server cache. However, when a change is made to a subpage or template, but not to the article page which transcludes it, the ''article page'' is not marked as "touched," and a new copy is not generated for the cache. Therefore anyone viewing the article page may see a cached page which includes old versions of the subpage or template.
+Normally, when a change is made, the page is marked as "touched" and the software will create a new copy of the page for the server cache. However, when a change is made to a subpage or template, but not to the article page which transcludes it, the ''article page'' is not marked as "touched," and a new copy is not immediately generated for the cache. Therefore anyone viewing the article page may see a cached page which includes old versions of the subpage or template.
-The purge command forces the server cache to purge the old version of the page. The next time the page is viewed, the page will be rebuilt from scratch, including fresh versions of all subpages and templates, and a new copy will be made for the server cache. Note that this may take a few minutes in extreme cases.
+The purge command forces the server cache to purge the old version of the page. The next time the page is viewed, the page will be rebuilt from scratch, including fresh versions of all subpages and templates, and a new copy will be made for the server cache.
+Note that this may take a few minutes in extreme cases. Given that it causes the servers more work, please avoid overusing the purge command.
-==For images==
-Purging an image's description page can be used to force the software to regenerate all the thumbnails for that particular image. If an image thumbnail will not regenerate successfully after the original image has been purged, it is probably because the server has cached an error page with the URL of a thumbnail, but the page is not purged because the actual thumbnail does not exist. The solution is to request the thumbnail with an unusual URL, say by appending ?1 to the end. The thumbnail should then be successfully generated. Finally, do action=purge to delete the cached error. You should only do this if you have tried an ordinary action=purge and it hasn't worked.
-==Related ==
+==See also==
-* [[Help:Bypass your cache]] - A general explanation of caching and how to clear your browser cache
+* [[Help:Bypass your cache]], a general explanation of caching and how to clear your browser cache
-* {{#NewWindowLink:homepage:w:User_blog:Wade_Warren/How_we_deliver_pages_to_you!|How we deliver pages to you!}} - A blog explaining why we use caching on Wikia and more on how it works
+* [[w:User_blog:Wade_Warren/How_we_deliver_pages_to_you!|How we deliver pages to you!]], a blog explaining why we use caching on Fandom and more on how it works
 [[ca:Ajuda:Actualitzar]]
 [[es:Ayuda:Actualizar]]
 [[fr:Aide:Purge]]
+[[it:Aiuto:Purgare la cache]]
-[[ja:ヘルプ:Purge]]
+[[ja:ヘルプ:パージ]]
 [[pl:Pomoc:Czyszczenie pamięci podręcznej]]
+[[pt:Ajuda:Purge]]
+[[ru:Справка:Purge]]
+[[tr:Yardım:Arındır]]
+[[uk:Довідка:Скидання кешу]]
+[[vi:Trợ giúp:Tẩy]]
+[[zh:help:Purge]]
 [[Category:Administration help]]
 [[Category:Help|{{PAGENAME}}]]