Mail queue limit?

[MattS]

I saw some interesting behavior today that resulted in JIRA outgoing email not being sent for 18 hours, so there were 26K mail items to send. The outgoing mail log had an error about the mail queue being considered stuck, which apparently stops all mail from being sent. So I bypassed that first stuck mail item and flushed the queue. The mail queue then grew to 45K mail items before JIRA was able to get ahead of the flood!

There were no large bulk updates or scripts making large numbers of edits or huge subscriptions that I could see. Does anyone have ideas on what might have caused this? I'm scratching my head at the moment.

Also, the mail queue page doesn't show 45K lines of mail items, but I couldn't find where the limit is set on how many it does show. Perhaps something about webwork iterator has a limit?

[Daniel Wester]

I've seen it happen when a listener is not able to work properly and blocks the single threaded mail queue. 

[GabrielleJ]

This happened to one of our instance and the culprit was the ALMQC Synchronizer (Orasi). I cannot remember the exact reason but maybe a big. We also have found several accounts that are already inactive (so their email address is invalid) and JIRA was trying to send email to those. What we did was to set those accounts to "INACTIVE" so JIRA won't send email to those anymore.