Date: Mon, 12 May 2008 09:35:46 +0200
From: Tino Schwarze <postgresql@tisc.de>
To: pgsql-admin@postgresql.org
Subject: Re: Orphan TOAST object
Message-ID: <20080512073546.GA30621@easy2.in-chemnitz.de>
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	<20553.1210525788@sss.pgh.pa.us>
	<8d01be800805111017w6910acdapaf66f0b56908d36e@mail.gmail.com>
	<20763.1210526763@sss.pgh.pa.us>
	<8d01be800805120025u3a49fa39rc7033a2480b4982f@mail.gmail.com>
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Hi James,

On Mon, May 12, 2008 at 09:25:34AM +0200, James Farrugia wrote:

> First of all thanks for the immediate replies!
> Was actually waiting for the right moment to upgrade to 8.3 but migrating a
> live 1Tb database is a bit daunting especially if you have never done it
> before (as in my case).  If I'm not mistaken i can upgrade to the latest
> minor version without having to dump and restore so I'll do that.

You need to check the release notes of the particulra minor release you
are upgrading to. Some minor releases also require a dump/restore cycle
because of bugfixes. You're lucky: 8.2.7 doesn't require dump/restore in
your case, the release notes say:
"A dump/restore is not required for those running 8.2.X"

> One last thing...can we run into data-loss problems with successfully
> vacuumed tables even if there is one unvacuumed database object; what would
> have happened if I ignored to vacuum that rogue pg_toast (which was the only
> unvacuumed object within the entire database)?

At a certain point, the server would have switched to "emergency mode"
and wouldn't have accepted any commands any more. See the description
here:
http://www.postgresql.org/docs/8.2/static/routine-vacuuming.html#VACUUM-FOR-WRAPAROUND

HTH,

Tino.

-- 
"What we resist, persists." (Zen saying)

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