Re: 2-phase commit

On Fri, 26 Sep 2003, Tom Lane wrote:

> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Tom Lane wrote:
> >> You're not considering the possibility of a transient communication
> >> failure.
>
> > Can't the master re-send the request after a timeout?
>
> Not "it can", but "it has to". The master *must* keep hold of that
> request forever (or until the slave responds, or until we reconfigure
> the system not to consider that slave valid anymore). Similarly, the
> slave cannot forget the maybe-committed transaction on pain of not being
> a valid slave anymore.

Hrmmmm ... is there no way of having part of the protocol being a message
sent back that its a valid/invalid slave? ie. slave has an uncommitted
transaction, never hears back from master to actually do the commit, so
after x-secs * y-retries any messages it does try to send to the master
have a bit flag set to 'invalid'?