Change Details

=== Error === Request ID: `W7bPjArAEHYAAC2B6EYAAABG ` ```name=message RuntimeException: Could not acquire lock for page ID '6548940'. ``` ```name=trace #0 /srv/mediawiki/php-1.32.0-wmf.24/includes/deferred/DeferredUpdates.php(268): LinksUpdate->doUpdate() #1 /srv/mediawiki/php-1.32.0-wmf.24/includes/deferred/DeferredUpdates.php(214): DeferredUpdates::runUpdate(LinksUpdate, Wikimedia\Rdbms\LBFactoryMulti, string, integer) #2 /srv/mediawiki/php-1.32.0-wmf.24/includes/deferred/DeferredUpdates.php(134): DeferredUpdates::execute(array, string, integer) #3 /srv/mediawiki/php-1.32.0-wmf.24/includes/MediaWiki.php(914): DeferredUpdates::doUpdates(string) #4 /srv/mediawiki/php-1.32.0-wmf.24/includes/MediaWiki.php(734): MediaWiki->restInPeace(string, boolean) #5 [internal function]: Closure$MediaWiki::doPostOutputShutdown() ``` === Impact === When the same page is edited repeatedly in a short period of time, the LinksUpdate process can fail. The exception is isolated in that it happens post-send (after the user has received a successful page response, so the error cannot be shown to the user), and is isolated by DeferredUpdates in that it is caught, reported and skipped without retry, but other DeferredUpdates do still run. This means there is no chance of cascading failure within the request. However, when LinksUpdate fails after an edit, it is currently final. Which means the database will be in an inconsistent state with regards to its derived data queries, such as Category membership, Language links, and WhatLinksHere, may be outdated or incorrect for the page in question, and does not automatically recover in an eventual way. === Notes === A similar issue was reported from RefreshLink jobs on the JobQueue as T170596, which we fixed. However, the issue still happens when multiple edits are made to the same page by the same or different users.

=== Error === Request ID: `W7bPjArAEHYAAC2B6EYAAABG ` ```name=message RuntimeException: Could not acquire lock for page ID '6548940'. ``` ```name=trace #0 /srv/mediawiki/php-1.32.0-wmf.24/includes/deferred/DeferredUpdates.php(268): LinksUpdate->doUpdate() #1 /srv/mediawiki/php-1.32.0-wmf.24/includes/deferred/DeferredUpdates.php(214): DeferredUpdates::runUpdate(LinksUpdate, Wikimedia\Rdbms\LBFactoryMulti, string, integer) #2 /srv/mediawiki/php-1.32.0-wmf.24/includes/deferred/DeferredUpdates.php(134): DeferredUpdates::execute(array, string, integer) #3 /srv/mediawiki/php-1.32.0-wmf.24/includes/MediaWiki.php(914): DeferredUpdates::doUpdates(string) #4 /srv/mediawiki/php-1.32.0-wmf.24/includes/MediaWiki.php(734): MediaWiki->restInPeace(string, boolean) #5 [internal function]: Closure$MediaWiki::doPostOutputShutdown() ``` === Impact === When the same page is edited repeatedly in a short period of time, the LinksUpdate process can fail. This particular exception was from edits at <https://en.wikipedia.org/w/index.php?title=Wikipedia:Version_1.0_Editorial_Team/Biography_(military)_articles_by_quality_log&offset=20181005024213&action=history>. Due to the high edit frequency there, the locks were unavailable and some of the edits had their update fail. When this happens for the "last" edit, which is not unlikely, it means the database will remain indefinitely in an incorrect state. Derived data such as used by category membership, language links, WhatLinksHere, and search, may return outdated or incorrect information about the page in question, and does not automatically recover in an eventual way. === Notes === A similar issue was reported from RefreshLink jobs on the JobQueue as T170596, which we fixed. However, the issue still happens when multiple edits are made to the same page by the same or different users.

=== Error === Request ID: `W7bPjArAEHYAAC2B6EYAAABG ` ```name=message RuntimeException: Could not acquire lock for page ID '6548940'. ``` ```name=trace #0 /srv/mediawiki/php-1.32.0-wmf.24/includes/deferred/DeferredUpdates.php(268): LinksUpdate->doUpdate() #1 /srv/mediawiki/php-1.32.0-wmf.24/includes/deferred/DeferredUpdates.php(214): DeferredUpdates::runUpdate(LinksUpdate, Wikimedia\Rdbms\LBFactoryMulti, string, integer) #2 /srv/mediawiki/php-1.32.0-wmf.24/includes/deferred/DeferredUpdates.php(134): DeferredUpdates::execute(array, string, integer) #3 /srv/mediawiki/php-1.32.0-wmf.24/includes/MediaWiki.php(914): DeferredUpdates::doUpdates(string) #4 /srv/mediawiki/php-1.32.0-wmf.24/includes/MediaWiki.php(734): MediaWiki->restInPeace(string, boolean) #5 [internal function]: Closure$MediaWiki::doPostOutputShutdown() ``` === Impact === When the same page is edited repeatedly in a short period of time, the LinksUpdate process can fail. The exception is isolated in that it happens post-send (after the user has received a successful page response,is particular exception was from edits at <https://en.wikipedia.org/w/index.php?title=Wikipedia:Version_1.0_Editorial_Team/Biography_(military)_articles_by_quality_log&offset=20181005024213&action=history>. sDue to the error cannot be shown to the user)high edit frequency there, and is isolated by DeferredUpdates in that it is caught,the locks were unavailable and some of the edits had their update fail. reported and skipped without retryWhen this happens for the "last" edit, but other DeferredUpdates do still run.which is not unlikely, Thisit means there is no chance of cascading failure within the requeste database will remain indefinitely in an incorrect state. However, when LinksUpdate fails after an edit, it is currently final. Which means the database will be in an inconsistent state with regards to its derived data queriesDerived data such as used by category membership, such as Category membershiplanguage links, Language lWhatLinksHere, and WhatLinksHeresearch, may bereturn outdated or incorrect forinformation about the page in question, and does not automatically recover in an eventual way. === Notes === A similar issue was reported from RefreshLink jobs on the JobQueue as T170596, which we fixed. However, the issue still happens when multiple edits are made to the same page by the same or different users.