Cron job FlaggedRevs/maintenance/updateStats.php is sending an email to root@ every 2 hours since April 9th. The messages contain warnings due to slow queries, which are irrelevant:
[Mon Apr 9 12:01:41 2018] [hphp] [30264:7fe7635c8200:0:000001] [] SlowTimer [60886ms] at runtime/ext_mysql: slow query: SELECT /* Wikimedia\Rdbms\Database::query */ rev_timestamp AS rt,(SELECT MIN(fr_timestamp) FROM `flaggedrevs` WHERE (fr_page_id = rev_page) AND (fr_rev_timestamp >= rev_timestamp) ) AS nft FROM `revision` WHERE (rev_user > 0) AND (rev_timestamp BETWEEN '20090630052123' AND '20090707052123') AND ((rev_id % 1) = 0) AND (rev_parent_id > 0) AND (EXISTS (SELECT * FROM `flaggedrevs` WHERE (fr_page_id = rev_page) AND (fr_rev_timestamp < rev_timestamp) AND (fr_rev_id < rev_id) AND (fr_timestamp < rev_timestamp) )) [Mon Apr 9 12:02:15 2018] [hphp] [30537:7f1b7a955200:0:000001] [] SlowTimer [19785ms] at runtime/ext_mysql: slow query: SELECT /* Wikimedia\Rdbms\Database::query */ rev_timestamp AS rt,(SELECT MIN(fr_timestamp) FROM `flaggedrevs` WHERE (fr_page_id = rev_page) AND (fr_rev_timestamp >= rev_timestamp) ) AS nft FROM `revision` WHERE (rev_user > 0) AND (rev_timestamp BETWEEN '20140312000108' AND '20140319000108') AND ((rev_id % 1) = 0) AND (rev_parent_id > 0) AND (EXISTS (SELECT * FROM `flaggedrevs` WHERE (fr_page_id = rev_page) AND (fr_rev_timestamp < rev_timestamp) AND (fr_rev_id < rev_id) AND (fr_timestamp < rev_timestamp) ))
There are so far 95 emails and counting. Warnings like this should be filtered and not be sent to error log. The large amount of mails masks other legitimate errors. Sending to standard output is ok when legitimate errors happen, but not in this case.