Re: SSI and 2PC

From: David Fetter <david(at)fetter(dot)org>
To: Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>
Cc: pgsql-hackers(at)postgresql(dot)org, Dan Ports <drkp(at)csail(dot)mit(dot)edu>, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, Jeff Davis <pgsql(at)j-davis(dot)com>
Subject: Re: SSI and 2PC
Date: 2011-01-10 14:52:34
Message-ID: 20110110145234.GD13020@fetter.org
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On Mon, Jan 10, 2011 at 08:49:12AM -0600, Kevin Grittner wrote:
> "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
>
> > In going back through old emails to see what issues might have
> > been raised but not yet addressed for the SSI patch, I found the
> > subject issue described in a review by Jeff Davis here:
> >
> > http://archives.postgresql.org/pgsql-hackers/2010-10/msg01159.php
>
> After reviewing the docs and testing things, I'm convinced that more
> work is needed. Because the transaction's writes aren't visible
> until COMMIT PREPARED is run, and write-write conflicts are still
> causing serialization failures after PREPARE TRANSACTION, some of
> the work being done for SSI on PREPARE TRANSACTION needs to be moved
> to COMMIT PREPARED.
>
> It seems likely that shops who use prepared transactions are more
> likely than most to care about truly serializable transactions, so I
> don't think I should write this off as a limitation for the 9.1
> implementation. Unless someone sees some dire problem with the
> patch which I've missed, this seems like my top priority to fix
> before cutting a patch.

Could people fix it after the patch? ISTM that a great way to test it
is to make very sure it's available ASAP to a wide range of people via
the next alpha (or beta, if that's where we're going next).

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
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