The aox flush queue command asks the running Archiveopteryx server to deliver all spooled mail to the smarthost at once.
Archiveopteryx spools mail for many reasons — autoreplies or vacation messages, forwarded mail, user-submitted messages, etc. All of those are stored in the deliveries table. Flush queue changes each row in that table so Archiveopteryx thinks it hasn't tried to deliver that message yet, then signals the running server to serve the queue.
Normally, messages stay in the queue only very briefly, so flush queue does nothing. If the smarthost is down or there is some other problems, then the spool may grow. Even in that case, flushing manually should not be necessary. But it's possible. Added by user request.
Last modified: 2010-11-19