Help:Job queue
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This is a copy of the master help page at Meta. Do not edit this copy.
Edits will be lost in the next update from the master page. See below for more information.
In MediaWiki 1.6, a job queue was introduced, to perform long-running tasks asynchronously. The job queue is designed to hold many short tasks. You can view the length of the job queue by visiting Special:Statistics on most 1.6 wikis. By default, each time a request runs, one job is taken from the job queue and executed. If the performance burden of this is too great, you can reduce $wgJobRunRate by putting something like this in your LocalSettings.php:
- $wgJobRunRate = 0.01;
You can also execute the job queue from the command line, by running maintenance/runJobs.php.
Why the job queue exists
Currently there is one application for the job queue: updating the links tables when a template changes.
The problem comes when you edit the template to use a different category. The template might be used on thousands of articles, updating the links for all of those articles would be much too slow to perform during the web request to save the article. So previous versions of MediaWiki didn't bother. The category membership wouldn't change, and it was necessary to do a "null edit" (that is, click save without making any changes), for each of the articles using the template.
MediaWiki 1.6 adds a job to the job queue for each article using the template. Each job is a command to read an article, expand any templates, and update the link table accordingly. So null edits are no longer necessary, although it may take a while for big operations to complete.
Bugs
As of version 1.7alpha (r14541), filling the job queue may fail when editing templates that are used thousands of times. See bugzilla:5527 for details and implications.
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Wikipedia-specific help
Template:Ph:Job queue
This page is a copy of the master help page at Meta (for general help information all Wikimedia projects can use), with two Wikipedia-specific templates inserted. To update the main text, edit the master help page for all projects at m:Help:Job queue. For Wikipedia-specific issues, use Template:Ph:Job queue (the extra text at the bottom of this page) or Template:Phh:Job queue for a Wikipedia-specific lead (text appears at the top of this page). You are welcome to copy the exact wikitext from the master page at Meta and paste it into this page at any time. To view this page in other languages see the master page at Meta.
