When dispatchChanges.php is run as a cronjob it seems like it (as least sometimes) doesn't close down as expected, and then doesn't release the database connections. After a while MySQL then runs out of free connections, and then Mediawiki and other processes on the server grinds to a halt.
Either a PID-file should be used to stop new processes from starting, or a proper close should be done, or a proper daemon should be made. Restarting new processes from crontab without knowing if the previous ones are properly closed is bad.
Version: unspecified
Severity: major
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=46643