From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Daniel Caune <daniel.caune@ubisoft.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Strang behaviour SELECT ... LIMIT n FOR UPDATE
Date: Wed, 28 Nov 2007 22:08:18 -0300
Message-ID: <20071129010818.GA5118@alvh.no-ip.org> (raw)
In-Reply-To: <24728.1196287704@sss.pgh.pa.us>
References: <1E293D3FF63A3740B10AD5AAD88535D2068A695E@UBIMAIL1.ubisoft.org>
<24728.1196287704@sss.pgh.pa.us>
Tom Lane wrote:
> "Daniel Caune" <daniel.caune@ubisoft.com> writes:
> > It seems that, in certain condition, row (199,84) is shadowing row
> > (3702,85);
>
> This would be the expected behavior if row (199,84) were an updated
> version of row (3702,85), but you couldn't see it yet in your current
> transaction snapshot. A plain SELECT would show the older version
> (the current one according to the snapshot) while SELECT FOR UPDATE
> would show the newest committed version.
Hmm. We've been studying a case on one customer where xmin/xmax seem to
be corrupted. It has had ups and downs because I have my doubts about
their storage system, but I'm not completely sure that it can be really
blamed.
This is on 8.1.10.
--
Alvaro Herrera Valdivia, Chile ICBM: S 39º 49' 18.1", W 73º 13' 56.4"
Major Fambrough: You wish to see the frontier?
John Dunbar: Yes sir, before it's gone.
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To: pgsql-sql@postgresql.org
Cc: alvherre@alvh.no-ip.org, tgl@sss.pgh.pa.us, daniel.caune@ubisoft.com
Subject: Re: Strang behaviour SELECT ... LIMIT n FOR UPDATE
In-Reply-To: <20071129010818.GA5118@alvh.no-ip.org>
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