Re: Strang behaviour SELECT ... LIMIT n FOR UPDATE

From: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Daniel Caune <daniel(dot)caune(at)ubisoft(dot)com>, pgsql-sql(at)postgresql(dot)org
Subject: Re: Strang behaviour SELECT ... LIMIT n FOR UPDATE
Date: 2007-11-29 01:08:18
Message-ID: 20071129010818.GA5118@alvh.no-ip.org
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-sql

Tom Lane wrote:
> "Daniel Caune" <daniel(dot)caune(at)ubisoft(dot)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.

In response to

Browse pgsql-sql by date

  From Date Subject
Next Message Gera Mel Handumon 2007-11-29 09:43:38 Re: NULLIF problem
Previous Message Tom Lane 2007-11-28 22:08:24 Re: Strang behaviour SELECT ... LIMIT n FOR UPDATE