Re: VACUUM FULL needed sometimes to prevent transaction

On Tue, 2006-08-22 at 20:10 +0200, Marinos Yannikos wrote:
> Hello,
>
> we're looking into the reason why we are getting warnings about
> transaction ID wraparound despite a daily "vaccumdb -qaz". Someone is
> claiming that VACUUM without FULL cannot reassign XIDs properly when
> max_fsm_pages was set too low (it says so here too, but this is rather
> old: http://www.varlena.com/GeneralBits/Tidbits/perf.html#maxfsmp). Is
> this true, or do we have a different issue here? We're using 8.1.3 with
> a database generated on 8.1.3 (i.e. not migrated from 7.x or anything
> like that).

Usually this is caused by either:
(1) You're not vacuuming as a superuser, so it's not able to vacuum
everything.
(2) You have a long-running transaction that never completed for some
strange reason.

Hope this helps,
Jeff Davis