Re: [GENERAL] Getting acces to MVCC version number - Mailing list pgsql-sql

From Tom Lane
Subject Re: [GENERAL] Getting acces to MVCC version number
Date
Msg-id 2566.1032557012@sss.pgh.pa.us
Whole thread Raw
In response to Getting acces to MVCC version number  (Jean-Luc Lachance <jllachan@nsd.ca>)
List pgsql-sql
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

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