Re: 2-phase commit

On Fri, 2003-09-26 at 13:58, Bruce Momjian wrote:
> Patrick Welche wrote:
> > On Fri, Sep 26, 2003 at 02:49:30PM -0300, Marc G. Fournier wrote:
> > ...
> > > if we are talking two computers sitting next to each other on a switch,
> > > you'd expect those to be low ... but if you were talking about two
> > > seperate geographical locations (and yes, I realize you are adding lag to
> > > the mix with waiting for responses), you'd expect those #s to rise ...
> >
> > Which I thought was the whole point of using a group communication protocol
> > such as spread in postgresql-r. It seemed solved there...
>
> Right, but I think we want to try to do two-phase commit without spread.
> Spread seems overkill for this usage.

Out of curiosity, how does one use spread to accomplish 2PC? Isn't the
logic the Application Server would need to follow rather different with
a group communication based control than with XA / 2PC style
communication? How does one map to the other?