Re: On "multi-master"

Andrew Sullivan <ajs@crankycanuck.ca> writes:
> On Thu, Oct 13, 2005 at 10:53:51AM -0700, Chris Travers wrote:
>> Now, what about PgPool as a multimaster sync replication solution?  Sure
>> it is statement level....  But is there any reason why you cannot have
>> multiple PgPool instances running against a number of DB servers?

> Well, to begin with, you have a serious race condition:

> pgpool begins T1 on M1 and M2.
> Someone logs into M2 and does some work in T2.
> M1 completes the work of T1.
> M2 completes the work of T2.
> pgpool issues COMMIT.
> M1 replies with the COMMIT.
> M2 detects a deadlock when T2 tries to COMMIT.

> Now what?

This particular issue is fixable as of 8.1: pgpool should be using
2-phase commit.

            regards, tom lane