Topic on Project:Support desk

Hi,

Some of our larger pages are taking a very long time to load, yet we have $wgMainCacheType set to CACHE_ACCEL and it is using APCu.

Installation details:

MediaWiki	1.22.6
PHP	        5.5.12-1~dotdeb.1 (fpm-fcgi)
MySQL	        5.6.15-63.0-log
Lua	        5.1.5

New Relic shows that most of the time is spent here:

PPFrame_DOM::expand 	87 	2,250 ms 	24%
Linker::makeImageLink 	464 	1,870 ms 	20%

Isn't this part of the rendering process that should be cached in APCu? If so, why would it not be working?

Another strange request has this:

page - SELECT 	608 	4,610 ms 	27%
Parser::replaceInternalLinks2 	1 	4,110 ms 	24%

With these queries:

Timestamp 	Total duration 	Call count 	SQL
4.770 s 	4,370 ms 	574 	SELECT /* LocalRepo::getArticleID Glen.? */ page_id FROM `page` WHERE page_namespace = ? AND page_title = ? LIMIT ?
8.777 s 	2,780 ms 	574 	SELECT /* LocalRepo::checkRedirect Glen.? */ rd_title, rd_namespace FROM `redirect` WHERE rd_from = ? LIMIT ?

Why on earth is it selecting from these tables 574 times in a single request!?

We have the following extensions:

Add_HTML_Meta_and_Title (Version 0.5)
Cite
EmbedVideo (Version 1.0)
Header Tabs (Version 0.9.3)
ParserFunctions (Version 1.5.1)
RSS feed (Version 2.24)
Scribunto
Widgets (Version 1.0)
--
Approved Revs (Version 0.6.6)
Google Analytics Integration (Version 2.0.2)

Any ideas what may be causing these issues?

Thanks,

Glen.

When debugging issues like this, its often good to disable extensions, as certain misbehaved extensions can sometimes cause performance problems (I haven't heard of any that you list as being misbehaving, but the general principle remains)

The problem is with the Approved Revs extension. I'm going to try to figure out why.