Maniphest T419018

ThreadItemStore::findNewestRevisionsByHeading uses primary DB method calls for replica DB query, causing thousands of TransactionProfiler warnings
Closed, ResolvedPublicPRODUCTION ERROR
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Authored By

	Dreamy_Jazz
	Mar 4 2026, 2:21 PM

Project Tags

Referenced Files

None

Subscribers

Aklapper

Dreamy_Jazz

Description

Summary

ThreadItemStore::findNewestRevisionsByHeading is interacting with the primary DB on GET requests to use methods such as IReadableDatabase::anyString and IReadableDatabaes::expr. This is causing 60,000 TransactionProfiler warnings a week. Instead a replica DB connection should be used to interact with these methods, as fetching the primary DB may cause MediaWiki to interact with the primary database itself (even without performing queries)

Error

f13ed9e6-94bf-4eb5-b4bc-762e705233e8

message

Expectation (masterConns <= 0) by MediaWiki\Api\ApiMain::setRequestExpectations not met (actual: 1):
[connect to db2212 (enwiki)]

trace

from /srv/mediawiki/php-1.46.0-wmf.17/includes/libs/Rdbms/TransactionProfiler.php(569)
#0 /srv/mediawiki/php-1.46.0-wmf.17/includes/libs/Rdbms/TransactionProfiler.php(302): Wikimedia\Rdbms\TransactionProfiler->reportExpectationViolated(string, string, int)
#1 /srv/mediawiki/php-1.46.0-wmf.17/includes/libs/Rdbms/LoadBalancer/LoadBalancer.php(810): Wikimedia\Rdbms\TransactionProfiler->recordConnection(string, string, bool)
#2 /srv/mediawiki/php-1.46.0-wmf.17/includes/libs/Rdbms/LoadBalancer/LoadBalancer.php(789): Wikimedia\Rdbms\LoadBalancer->getServerConnection(int, string, int)
#3 /srv/mediawiki/php-1.46.0-wmf.17/includes/libs/Rdbms/Database/DBConnRef.php(109): Wikimedia\Rdbms\LoadBalancer->getConnectionInternal(int, array, string, int)
#4 /srv/mediawiki/php-1.46.0-wmf.17/includes/libs/Rdbms/Database/DBConnRef.php(127): Wikimedia\Rdbms\DBConnRef->ensureConnection()
#5 /srv/mediawiki/php-1.46.0-wmf.17/includes/libs/Rdbms/Database/DBConnRef.php(638): Wikimedia\Rdbms\DBConnRef->__call(string, array)
#6 /srv/mediawiki/php-1.46.0-wmf.17/extensions/DiscussionTools/includes/ThreadItemStore.php(187): Wikimedia\Rdbms\DBConnRef->anyString()
#7 /srv/mediawiki/php-1.46.0-wmf.17/extensions/DiscussionTools/includes/ApiDiscussionToolsFindComment.php(60): MediaWiki\Extension\DiscussionTools\ThreadItemStore->findNewestRevisionsByHeading(string, int, MediaWiki\Title\TitleValue)
#8 /srv/mediawiki/php-1.46.0-wmf.17/includes/Api/ApiMain.php(2062): MediaWiki\Extension\DiscussionTools\ApiDiscussionToolsFindComment->execute()
#9 /srv/mediawiki/php-1.46.0-wmf.17/includes/Api/ApiMain.php(967): MediaWiki\Api\ApiMain->executeAction()
#10 /srv/mediawiki/php-1.46.0-wmf.17/includes/Api/ApiMain.php(938): MediaWiki\Api\ApiMain->executeActionWithErrorHandling()
#11 /srv/mediawiki/php-1.46.0-wmf.17/includes/Api/ApiEntryPoint.php(138): MediaWiki\Api\ApiMain->execute()
#12 /srv/mediawiki/php-1.46.0-wmf.17/includes/MediaWikiEntryPoint.php(180): MediaWiki\Api\ApiEntryPoint->execute()
#13 /srv/mediawiki/php-1.46.0-wmf.17/api.php(30): MediaWiki\MediaWikiEntryPoint->run()
#14 /srv/mediawiki/w/api.php(3): require(string)
#15 {main}

Acceptance criteria

The TransactionProfiler warnings are no longer created

Details

Related Changes in Gerrit:

	Subject	Author	Repo	Branch	Lines +/-
	ThreadItemStore: Don't use primary DB when building queries for replica DB	Bartosz Dziewoński	mediawiki/extensions/DiscussionTools	master	+11 -11

Customize query in gerrit

Event Timeline

Dreamy_Jazz created this task.Mar 4 2026, 2:21 PM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptMar 4 2026, 2:21 PM

Dreamy_Jazz renamed this task from ThreadItemStore::findNewestRevisionsByHeading uses primary DB for ::anyString and ::expr method calls when querying a replica DB, causing TransactionProfiler warnings to ThreadItemStore::findNewestRevisionsByHeading uses primary DB for ::anyString and ::expr method calls when querying a replica DB, causing thousands of TransactionProfiler warnings.Mar 4 2026, 3:16 PM

Dreamy_Jazz renamed this task from ThreadItemStore::findNewestRevisionsByHeading uses primary DB for ::anyString and ::expr method calls when querying a replica DB, causing thousands of TransactionProfiler warnings to ThreadItemStore::findNewestRevisionsByHeading uses primary DB method calls for replica DB query, causing thousands of TransactionProfiler warnings.

Change #1248036 had a related patch set uploaded (by Bartosz Dziewoński; author: Bartosz Dziewoński):

[mediawiki/extensions/DiscussionTools@master] ThreadItemStore: Don't use primary DB when building queries for replica DB

https://gerrit.wikimedia.org/r/1248036

gerritbot added a project: Patch-For-Review.Mar 4 2026, 4:11 PM

Change #1248036 merged by jenkins-bot:

[mediawiki/extensions/DiscussionTools@master] ThreadItemStore: Don't use primary DB when building queries for replica DB

https://gerrit.wikimedia.org/r/1248036

ReleaseTaggerBot added a project: MW-1.46-notes (1.46.0-wmf.19; 2026-03-10).Mar 4 2026, 6:00 PM

Maintenance_bot removed a project: Patch-For-Review.Mar 4 2026, 6:31 PM

matmarex closed this task as Resolved.Mar 4 2026, 6:33 PM

matmarex claimed this task.

Thanks for the quick fix!

ThreadItemStore::findNewestRevisionsByHeading uses primary DB method calls for replica DB query, causing thousands of TransactionProfiler warningsClosed, ResolvedPublicPRODUCTION ERRORActions