Re: Transaction ID wrap limit is log entries

On Mon, May 20, 2013 at 3:11 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Armand du Plessis <adp(at)bank(dot)io> writes:
> > The autovacuum completed (after many hours) however it didn't seem to
> have
> > frozen any old pages as it just kicks off again right away with the same
> > reason (VACUUM ANALYZE public.messages (to prevent wraparound))
>
> I suspect it's unable to move the table's min XID forward at all because
> there is some old open transaction preventing cleanup of very old dead
> tuples. Look for old xact_start times in pg_stat_activity. Also look
> for old entries in pg_prepared_xacts. If you find any, get rid of them.
>

Thanks Tom, that sounds like it possibly could've caused it. I've since
restarted the cluster (kicking myself) so there's no old transactions left
in either table. (pg_prepared_xacts is actually empty). Will check there
first if this happens again.

> regards, tom lane
>