Re: autovacuum not prioritising for-wraparound tables

On Thu, Jan 24, 2013 at 1:57 PM, Alvaro Herrera
<alvherre(at)2ndquadrant(dot)com> wrote:
> Hi,
>
> I have a bug pending that autovacuum fails to give priority to
> for-wraparound tables. When xid consumption rate is high and dead tuple
> creation is also high, it is possible that some tables are waiting for
> for-wraparound vacuums that don't complete in time because the workers
> are busy processing other tables that have accumulated dead tuples; the
> system is then down because it's too near the Xid wraparound horizon.
> Apparently this is particularly notorious in connection with TOAST
> tables, because those are always put in the tables-to-process list after
> regular tables.

Is something killing off your autovacuum workers routinely, such that
they rarely reach the end of their to-do list?

Otherwise it seems like the tables would come up for vacuuming in a
cyclic fashion, staggered for each worker; and it being a circle it
shouldn't systematically matter where in it they were added.

What are the various settings for vacuuming?

Cheers,

Jeff