Re: Two-phase commit

On Wed, 2004-10-06 at 18:50, Tom Lane wrote:
> Oliver Jowett <oliver@opencloud.com> writes:
> >> At the API level, I like the PREPARE/COMMIT/ROLLBACK statements, but I
> >> think you have missed a bet in that it needs to be possible to issue
> >> "COMMIT PREPARED gid" for the same gid several times without error.
> 
> > Isn't this usually where the GTM would issue "recover" requests to 
> > determine the state of the individual resources involved in the global 
> > transaction, and then only commit/abort the resources that need it? (I 
> > think the equivalent in Heikki's work is a SELECT of the 
> > pg_prepared_xact view)
> 
> Well, the question is how long must the individual databases retain
> state with which to answer "recover" requests.  I don't like "forever",
> so I'm proposing that there should be an explicit command to say "you
> can forget about this gid".

Isn't this exactly what the "forget" request is for in the
XACoordinator? I think it's standard for Java at the very least.