As @Gilles noted in T240201#6602256, there were some particularly slow load times recently for Special:Homepage.
Looking at the last two days there are some spikes:
Looking at Logstash for those spikes, we see a lot of entries like this:
Expectation (readQueryTime <= 5) by MediaWiki::main not met (actual: 59.928746938705): query-m: SELECT tl_from,tl_title FROM `templatelinks` WHERE (tl_from = N AND tl_title IN ('X') AND tl_namespace = N) [TRX#09f194]
Where the trace looks like this:
#0 /srv/mediawiki/php-1.36.0-wmf.14/includes/libs/rdbms/TransactionProfiler.php(254): Wikimedia\Rdbms\TransactionProfiler->reportExpectationViolated(string, Wikimedia\Rdbms\GeneralizedSql, double) #1 /srv/mediawiki/php-1.36.0-wmf.14/includes/libs/rdbms/database/Database.php(1412): Wikimedia\Rdbms\TransactionProfiler->recordQueryCompletion(Wikimedia\Rdbms\GeneralizedSql, double, boolean, integer) #2 /srv/mediawiki/php-1.36.0-wmf.14/includes/libs/rdbms/database/Database.php(1294): Wikimedia\Rdbms\Database->executeQueryAttempt(string, string, boolean, string, integer) #3 /srv/mediawiki/php-1.36.0-wmf.14/includes/libs/rdbms/database/Database.php(1223): Wikimedia\Rdbms\Database->executeQuery(string, string, integer) #4 /srv/mediawiki/php-1.36.0-wmf.14/includes/libs/rdbms/database/Database.php(1907): Wikimedia\Rdbms\Database->query(string, string, integer) #5 /srv/mediawiki/php-1.36.0-wmf.14/extensions/GrowthExperiments/includes/NewcomerTasks/TemplateFilter.php(137): Wikimedia\Rdbms\Database->select(string, array, string, string) #6 /srv/mediawiki/php-1.36.0-wmf.14/extensions/GrowthExperiments/includes/NewcomerTasks/TemplateFilter.php(57): GrowthExperiments\NewcomerTasks\TemplateFilter->buildResultsMap(GrowthExperiments\NewcomerTasks\Task\TaskSet) #7 /srv/mediawiki/php-1.36.0-wmf.14/extensions/GrowthExperiments/includes/NewcomerTasks/TaskSuggester/CacheDecorator.php(78): GrowthExperiments\NewcomerTasks\TemplateFilter->filter(GrowthExperiments\NewcomerTasks\Task\TaskSet) #8 /srv/mediawiki/php-1.36.0-wmf.14/includes/libs/objectcache/wancache/WANObjectCache.php(1548): GrowthExperiments\NewcomerTasks\TaskSuggester\CacheDecorator->GrowthExperiments\NewcomerTasks\TaskSuggester\{closure}(GrowthExperiments\NewcomerTasks\Task\TaskSet, integer, array, double, array) #9 /srv/mediawiki/php-1.36.0-wmf.14/includes/libs/objectcache/wancache/WANObjectCache.php(1376): WANObjectCache->fetchOrRegenerate(string, integer, Closure, array, array) #10 /srv/mediawiki/php-1.36.0-wmf.14/extensions/GrowthExperiments/includes/NewcomerTasks/TaskSuggester/CacheDecorator.php(102): WANObjectCache->getWithSetCallback(string, integer, Closure, array) #11 /srv/mediawiki/php-1.36.0-wmf.14/extensions/GrowthExperiments/includes/HomepageModules/SuggestedEdits.php(323): GrowthExperiments\NewcomerTasks\TaskSuggester\CacheDecorator->suggest(User, array, array) #12 /srv/mediawiki/php-1.36.0-wmf.14/extensions/GrowthExperiments/includes/HomepageModules/SuggestedEdits.php(248): GrowthExperiments\HomepageModules\SuggestedEdits->getTaskSet() #13 /srv/mediawiki/php-1.36.0-wmf.14/extensions/GrowthExperiments/includes/Specials/SpecialHomepage.php(381): GrowthExperiments\HomepageModules\SuggestedEdits->getJsData(string) #14 /srv/mediawiki/php-1.36.0-wmf.14/extensions/GrowthExperiments/includes/Specials/SpecialHomepage.php(162): GrowthExperiments\Specials\SpecialHomepage->outputJsData(string, array) #15 /srv/mediawiki/php-1.36.0-wmf.14/includes/specialpage/SpecialPage.php(600): GrowthExperiments\Specials\SpecialHomepage->execute(NULL) #16 /srv/mediawiki/php-1.36.0-wmf.14/includes/specialpage/SpecialPageFactory.php(1018): SpecialPage->run(NULL) #17 /srv/mediawiki/php-1.36.0-wmf.14/includes/MediaWiki.php(307): MediaWiki\SpecialPage\SpecialPageFactory->executePath(Title, RequestContext) #18 /srv/mediawiki/php-1.36.0-wmf.14/includes/MediaWiki.php(940): MediaWiki->performRequest() #19 /srv/mediawiki/php-1.36.0-wmf.14/includes/MediaWiki.php(543): MediaWiki->main() #20 /srv/mediawiki/php-1.36.0-wmf.14/index.php(53): MediaWiki->run() #21 /srv/mediawiki/php-1.36.0-wmf.14/index.php(46): wfIndexMain() #22 /srv/mediawiki/w/index.php(3): require(string) #23 {main}
It looks like almost all of these are happening on cswiki.
The configuration at MediaWiki:NewcomerTasks.json has not changed recently.