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Maniphest T293828

Not Wikilambda test wiki exceeding 1G of memory on main page
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Description

The Not Wikilambda test wiki currently can’t load the main page – I bumped the maximum PHP memory to 1 GiB(!) and it’s still running out:

error.log
2021-10-19 20:40:01: (mod_fastcgi.c.421) FastCGI-stderr: PHP Fatal error:  Allowed memory size of 1073741824 bytes exhausted (tried to allocate 135168 bytes) in /data/project/notwikilambda/public_html/w/extensions/WikiLambda/includes/Registry/ZTypeRegistry.php on line 291
2021-10-19 20:40:44: (mod_fastcgi.c.421) FastCGI-stderr: PHP Fatal error:  Allowed memory size of 1073741824 bytes exhausted (tried to allocate 20480 bytes) in /data/project/notwikilambda/public_html/w/vendor/symfony/yaml/Parser.php on line 1102

I don’t remember what the memory limits in production are (and if this would already exceed them), but I think this deserves some looking into.

Note that some other pages work fine:

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LucasWerkmeister created this task.Oct 19 2021, 8:48 PM
Restricted Application added a subscriber: Aklapper. · View Herald TranscriptOct 19 2021, 8:48 PM
LucasWerkmeister added a comment.Oct 19 2021, 8:55 PM

I removed the transclusion of Special:PrefixIndex/Z via the API sandbox and that makes the main page render relatively quickly again. Consistently with this, directly visiting Special:PrefixIndex/Z also runs out of memory.

Stashbot added a comment.Oct 19 2021, 8:56 PM

Mentioned in SAL (#wikimedia-cloud) [2021-10-19T20:56:41Z] <wm-bot> <lucaswerkmeister> previous log messages all related to T293828

LucasWerkmeister added a comment.Oct 19 2021, 8:58 PM

IMHO at this point that’s something for the Abstract Wikipedia team to investigate: why listing a bunch of ZObject pages requires so much memory. (Let me know if you need more details about the wiki setup.)

LucasWerkmeister added a comment.EditedOct 19 2021, 9:04 PM

Along similar lines, loading recent changes with larger limits (e.g. 50 changes, 7 days) is also broken, though stricter limits (e.g. 1 change or 1 hour) work fine. I’m not sure how many of these error lines belong to RecentChanges requests (the first one is a main page request, 20:55 matches the previous Phabricator comment), but at least some of the RecentChanges requests resulted in timeout instead of OOM:

error.log
2021-10-19 20:55:21: (mod_fastcgi.c.421) FastCGI-stderr: PHP Fatal error:  Allowed memory size of 1073741824 bytes exhausted (tried to allocate 20480 bytes) in /data/project/notwikilambda/public_html/w/vendor/wikimedia/php-session-serializer/src/Wikimedia/PhpSessionSerializer.php on line 380
2021-10-19 20:58:45: (mod_fastcgi.c.421) FastCGI-stderr: PHP Fatal error:  Allowed memory size of 1073741824 bytes exhausted (tried to allocate 20480 bytes) in /data/project/notwikilambda/public_html/w/extensions/WikiLambda/includes/Registry/ZTypeRegistry.php on line 291
2021-10-19 21:00:26: (mod_fastcgi.c.421) FastCGI-stderr: PHP Fatal error:  Maximum execution time of 30 seconds exceeded in /data/project/notwikilambda/public_html/w/vendor/opis/json-schema/src/ValidationResult.php on line 133
2021-10-19 21:00:46: (mod_fastcgi.c.421) FastCGI-stderr: PHP Fatal error:  Maximum execution time of 30 seconds exceeded in /data/project/notwikilambda/public_html/w/vendor/symfony/yaml/Parser.php on line 655
2021-10-19 21:02:55: (mod_fastcgi.c.421) FastCGI-stderr: PHP Fatal error:  Maximum execution time of 30 seconds exceeded in /data/project/notwikilambda/public_html/w/vendor/symfony/yaml/Parser.php on line 1102
2021-10-19 21:03:06: (mod_fastcgi.c.421) FastCGI-stderr: PHP Fatal error:  Maximum execution time of 30 seconds exceeded in /data/project/notwikilambda/public_html/w/extensions/WikiLambda/includes/ZObjectContent.php on line 242
2021-10-19 21:03:20: (http-header-glue.c.1250) read(): Connection reset by peer 7 20
2021-10-19 21:03:20: (gw_backend.c.2149) response not received, request sent: 1822 on socket: unix:/var/run/lighttpd/php.socket.notwikilambda-1 for /w/index.php?title=Special:RecentChanges&hidebots=1&limit=50&days=7&enhanced=1&urlversion=2, closing connection

IMHO that falls under the same category of “listing enough ZObject pages is more expensive than it should be”.

LucasWerkmeister added a project: Abstract Wikipedia team.Oct 19 2021, 9:09 PM

(adding general tag, phase to be determined)

DVrandecic moved this task from To triage to Phase θ – Throttling on the Abstract Wikipedia team board.Oct 20 2021, 4:20 PM
DVrandecic edited projects, added Abstract Wikipedia team (Phase θ – Throttling); removed Abstract Wikipedia team.
Jdforrester-WMF added a parent task: T303353: Adjust system design to avoid significant performance bottlenecks.Mar 8 2022, 11:11 PM
Jdforrester-WMF added a project: Performance Issue.May 24 2022, 6:53 PM
Jdforrester-WMF moved this task from Incoming to Ready to do on the Abstract Wikipedia team (Phase θ – Throttling) board.
ori closed this task as Invalid.Aug 4 2022, 2:49 PM
ori subscribed.

I profiled a request to Special:PrefixIndex/Z on the Beta Cluster. The profile shows peak memory usage of 18MB.

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