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Maniphest T105852

action=info times out with an unfriendly error message on certain pages
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Description

Go to a page like https://en.wikipedia.org/wiki/Wikipedia:Sandbox?action=info. The following message appears, without any skin interface:

A database query error has occurred. This may indicate a bug in the software.

    Function: InfoAction::pageCounts
    Error: 2013 Lost connection to MySQL server during query (10.64.48.27)

Presumably what this really means is that some sort of internal timeout has occurred.

Ideally the error should be reported in a more friendly fashion. It is not, after all, a "bug in the software" that the error occurs; it's just a DB timeout.

Or, even better, handle these internal timeouts more cleanly and just present the action=info page without the unavailable information.

Details

ProjectBranchLines +/-Subject
mediawiki/coremaster+6 -5InfoAction: Use watchlist query group for watchlist queries
Customize query in gerrit

Related Objects

Event Timeline

TTO created this task.Jul 15 2015, 2:34 AM
TTO raised the priority of this task from to Needs Triage.
TTO updated the task description. (Show Details)
TTO added projects: Wikimedia-production-error, MediaWiki-General.
TTO added a subscriber: TTO.
Restricted Application added a subscriber: Aklapper. · View Herald TranscriptJul 15 2015, 2:34 AM
demon added a subscriber: demon.Jul 15 2015, 2:39 AM

Maybe T67332 is the underlying bug?

Reedy added a subscriber: Reedy.Jul 15 2015, 2:39 AM

I think we have a long running query killer. So handling better would be a good start

MZMcBride added a subscriber: MZMcBride.Jul 15 2015, 2:40 AM
demon triaged this task as Medium priority.Jul 15 2015, 2:41 AM
demon moved this task from Untriaged to Dec2019/1.35.wmf.10+ on the Wikimedia-production-error board.
MZMcBride mentioned this in T67332: InfoAction::pageCounts makes slow query based on rev_user_text (now uses rev_actor instead?).Jul 15 2015, 2:51 AM
Nemo_bis mentioned this in T51506: Implement "actual watchers" count into MediaWiki's info action.Jul 15 2015, 8:39 AM
Ricordisamoa added a subscriber: Ricordisamoa.Jul 15 2015, 2:31 PM
Nemo_bis added a subscriber: Nemo_bis.Jul 16 2015, 8:16 AM

Does this happen anywhere outside en.wiki, by the way? The English Wikipedia is special because it has a separate server for watchlist queries (as IIRC no other one has). Are we using it when appropriate? Is 10.64.48.27 that one?

Nemo_bis edited projects, added Wikimedia-Rdbms; removed MediaWiki-General.Jul 16 2015, 8:17 AM
Nemo_bis set Security to None.
Umherirrender added subscribers: Springle, greg.Jul 16 2015, 7:33 PM
Krenair added a subscriber: Krenair.EditedJul 16 2015, 8:41 PM
In T105852#1456476, @Nemo_bis wrote:

Does this happen anywhere outside en.wiki, by the way? The English Wikipedia is special because it has a separate server for watchlist queries (as IIRC no other one has). Are we using it when appropriate? Is 10.64.48.27 that one?

10.64.48.27 = db1072, but s1's server with watchlist listed in wmf-config/db-eqiad.php is db1055 (10.64.32.25).
We're not using that specific group for watchlist queries in action=info. I'll upload a patch to do that.

gerritbot added a subscriber: gerritbot.Jul 16 2015, 8:43 PM

Change 225227 had a related patch set uploaded (by Alex Monk):
InfoAction: Use watchlist query group for watchlist queries

https://gerrit.wikimedia.org/r/225227

gerritbot added a project: Patch-For-Review.Jul 16 2015, 8:43 PM
gerritbot added a comment.Jul 16 2015, 9:40 PM

Change 225227 merged by jenkins-bot:
InfoAction: Use watchlist query group for watchlist queries

https://gerrit.wikimedia.org/r/225227

Krenair mentioned this in rMWa2e0bf218649: InfoAction: Use watchlist query group for watchlist queries.Jul 16 2015, 9:41 PM
Forrestbot added projects: MW-1.26-release, WMF-deploy-2015-07-21_(1.26wmf15).Jul 16 2015, 10:00 PM
Krenair added a comment.Jul 16 2015, 10:22 PM

Do we just want to leave this open and see if the situation improves when this arrives on wikipedias?

Krenair removed a project: Patch-For-Review.Jul 16 2015, 10:22 PM
Nemo_bis added a comment.Jul 18 2015, 9:54 AM

Thank for the quick patch! Yes, no hurry to close.

Bawolff added a subscriber: Bawolff.Jul 18 2015, 10:22 AM
TTO added a comment.Jul 27 2015, 1:23 PM

The situation is no different to before. Did the patch really go out with 1.26wmf15?

Krenair added a comment.Jul 27 2015, 2:32 PM

Yep.

Elitre added a subscriber: Elitre.Jul 29 2015, 3:55 PM
Glaisher added a subscriber: Glaisher.Sep 5 2015, 3:51 PM
TTO closed this task as Resolved.Oct 17 2015, 12:26 PM
TTO claimed this task.

Seems to work properly now! It was kinda slow the first time I visited https://en.wikipedia.org/wiki/Wikipedia:Sandbox?action=info, but subsequently it is very fast. I wonder what changed?

Nemo_bis added a comment.Oct 21 2015, 7:33 PM

Interesting indeed, several other pathological cases seem fine too now. Curiously, just yesterday we had

10:41 jynus: potential extra load on mediawiki recent changes and watchlist on enwiki, please report any slowdown

demon moved this task from Dec2019/1.35.wmf.10+ to Resolved on the Wikimedia-production-error board.Oct 26 2015, 4:37 PM
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