Re: two phase commit

On Fri, 2007-07-20 at 15:26 -0400, Andrew Sullivan wrote:
> On Thu, Jul 19, 2007 at 03:13:27PM -0700, Ben wrote:
> > What corner case reduces 2pc from "guaranteed" to "very high probability"?
> > Is the worry if somebody leaves transactions in a prepared state for
> > weeks, only to find that deadlock issues has arrisen at final commit time?
>
> That's not the worry, no. But something _else_ could happen. For
> instance, recently it turned out that there was a way, using 2PC, to
> lock everybody out of the database. The only remedy to that at the
> moment is to blow away all the PREPAREd transactions, which could
> mean you lose something that was already committed to.
>

To clarify, I think you're referring to this:

http://archives.postgresql.org/pgsql-hackers/2007-07/msg00245.php

which can only be done as superuser locking a system table.

I would classify that as a "catastrophic" problem, since it involves
manually modifying $PGDATA.

Regards,
Jeff Davis