User "Catrope" posted a comment on MediaWiki.r101507. Full URL: http://www.mediawiki.org/wiki/Special:Code/MediaWiki/101507#c25301 Commit summary:
Re-apply Vitaliy Filippov's patch from Bug #29283 with a modification to make it work when no ACCEL cache is available. Comment: This is because the default value for ['store'] is 'detect', which now prefers APC over CDB. So on wikis with APC enabled where ['store'] is not overridden in the config, LC will automatically switch to using APC where it previously used CDB. This is normally not an issue, because an empty cache is simply repopulated. However, if ['manualRecache'] is enabled, empty caches cause an error. We could announce this as a scaptrap/breaking change, but I think it would be better to put APC at the bottom of the priority list, so a wiki won't suddenly decide to abandon another caching backend (CDB or DB) in favor of APC after enabling this code. Another reason is that on multi-server setups, LC in APC wouldn't be very efficient (every server has its own cache) whereas a DB cache is automatically synchronized and a CDB cache can be synchronized (I think TWN does the latter, and I think that's why they use manualRecache; WMF lets each server rebuild its own LC using CDB but I've been trying to talk Tim out of that). However, APC is typically enabled on these servers anyway, not for key-value caching but for opcode caching. The final nail in the coffin for me is that the APC cache is not accessible from maintenance scripts. I believe Brion is very wary of APC caching for this reason, and expressed doubts as to whether we should even continue to support it. It sounds to me like, given that problem, we probably shouldn't be enabling APC by default for anything. _______________________________________________ MediaWiki-CodeReview mailing list [email protected] https://lists.wikimedia.org/mailman/listinfo/mediawiki-codereview
