To: Alvaro Herrera <alvherre@alvh.no-ip.org>
cc: Kevin Grittner <kevin.grittner@wicourts.gov>,
	"pgsql-admin@postgresql.org" <pgsql-admin@postgresql.org>,
	Ireneusz Pluta <ipluta@wp.pl>
Subject: Re: Autovacuum and invalid page header 
In-reply-to: <1273811839-sup-7071@alvh.no-ip.org> 
References: <4BEA8CD0.8070108@wp.pl>
 <4BEBC57002000025000316A3@gw.wicourts.gov>
	<1273811839-sup-7071@alvh.no-ip.org>
Comments: In-reply-to Alvaro Herrera <alvherre@alvh.no-ip.org>
	message dated "Fri, 14 May 2010 00:40:41 -0400"
Date: Fri, 14 May 2010 00:50:39 -0400
Message-ID: <14800.1273812639@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> Yeah, maybe we should make it put the failed table at the end of the
> list, for the next run.  This is not simple to implement, if only
> because autovac workers don't have any way to persist state from one run
> to the next.  But this kind of thing causes enough problems that it's
> probably worth it.

> One thing to keep in mind, though, is that a persistent error in a
> single table is enough to keep a database's datfrozenxid from advancing,
> and thus shut down in case the wraparound horizon comes too close.  So
> perhaps what we need is more visibility into autovacuum problems.

+1 for the latter.  A recurrent vacuum failure is something that needs
to be dealt with ASAP, not partially-worked-around.

			regards, tom lane