Message-ID: <3D8F3775.B5DD079@nsd.ca>
Date: Mon, 23 Sep 2002 11:47:01 -0400
From: Jean-Luc Lachance <jllachan@nsd.ca>
MIME-Version: 1.0
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-sql@postgresql.org, pgsql-general@postgresql.org
Subject: Re: Getting acces to MVCC version number
References: <200209201619.g8KGJ4J00624@candle.pha.pa.us>
	<3D8B676D.3109ACFA@nsd.ca> <2566.1032557012@sss.pgh.pa.us>
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That is great!  Thanks for the info.

Tom Lane wrote:
> 
> Jean-Luc Lachance <jllachan@nsd.ca> writes:
> > How about making available the MVCC last version number just like oid is
> > available.  This would simplify a lot of table design.  You know, having
> > to add a field "updated::timestamp" to detect when a record was updated
> > while viewing it (a la pgaccess).
> > That way, if the version number do not match, one would know that the
> > reccord was updated since last retrieved.
> 
> > What do think?
> 
> I think it's already there: see xmin and cmin.  Depending on your needs,
> testing xmin might be enough (you'd only need to pay attention to cmin
> if you wanted to notice changes within your own transaction).
> 
>                         regards, tom lane