Re: Processing a work queue

"John D. Burger" <john@mitre.org> writes:
> I decided to run a periodic vacuum on my work queue.  Lo and behold,
> I get this:

>    ERROR:  tuple concurrently updated

Which PG version is this, and do you have autovacuum enabled?  Awhile
back it was possible to get this error if autovac and a manual vacuum
hit the same table concurrently (the error actually stems from trying
to update pg_statistic concurrently during the ANALYZE phase).

> In addition, all of my workers locked up, apparently indefinitely.

[ squint... ]  That shouldn't happen.  Look into pg_locks to see if
you can determine who's waiting for what.

            regards, tom lane