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.
On any article page:
- At the end of the URL add the text
- Visit that link; the page should be refreshed in a short time
Note, if the URL includes an
anchor, remove that part before adding the purge code.
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.