Re: [GENERAL] Using xmin and xmax for optimistic locking - Mailing list pgsql-general

From Karsten Hilbert
Subject Re: [GENERAL] Using xmin and xmax for optimistic locking
Date
Msg-id 20170220213804.jny7qdparhz5nd6p@hermes.hilbert.loc
Whole thread Raw
In response to Re: [GENERAL] Using xmin and xmax for optimistic locking  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
On Mon, Feb 20, 2017 at 04:22:51PM -0500, Tom Lane wrote:

> One other thought here --- if you do want to go with the "no other
> updates" semantics, it still seems like it should be sufficient to
> compare xmins.  Comparing the xmax values would add nothing to that,
> except that it would reject if another update had been attempted and
> then failed, which seems undesirable.

Right, we have been doing that (xmin only) in GNUmed for
years in order to detect concurrent updates to our medical
record. Works like a charm.

Karsten
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