Re: 2PC-induced lockup

On Wed, 2007-07-11 at 22:33 +0100, Heikki Linnakangas wrote:
> Andrew Sullivan wrote:
> > On Wed, Jul 11, 2007 at 09:26:34PM +0100, Heikki Linnakangas wrote:
> >> The xid is encoded in the filename. If you can't start up the database
> >> and look at pg_locks, you can't do much other than guess.
> >
> > So then in this sort of case, it isn't _really_ safe to delete those
> > files, because the commitment you made before crash when you accepted
> > a PREPARE TRANSACTION is going to be gone, which violates the 2PC
> > rules.
>
> Yes, though if neither you nor the transaction manager can connect, you
> don't have much choice.

True, but I'm worried that this discussion will lead, via Google, to the
impression that if you are having connection problems the best thing to
do is to delete everything in pg_twophase. There are hundreds of other
issues that might prevent connection and it would require significant
expertise to isolate this as the error. I would prefer to explicitly
avoid this kind of error, so that we can return to the idea that
removing pg_twophase is never a requirement.

--
Simon Riggs
EnterpriseDB http://www.enterprisedb.com