Horton

Re: 2-phase commit

Rod Taylor <rbt@rbt.ca>

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From: Rod Taylor <rbt@rbt.ca>
To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Patrick Welche <prlw1@newn.cam.ac.uk>, "Marc G. Fournier" <scrappy@postgresql.org>, Tom Lane <tgl@sss.pgh.pa.us>, Zeugswetter Andreas SB SD <ZeugswetterA@spardat.at>, Andrew Sullivan <andrew@libertyrms.info>, PostgreSQL Development <pgsql-hackers@postgresql.org>
Date: 2003-09-26T20:53:46Z
Lists: pgsql-hackers 
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?