Re: pgsql: Fix a couple of bugs in MultiXactId freezing - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: pgsql: Fix a couple of bugs in MultiXactId freezing
Date
Msg-id 20131216163101.GI12902@eldon.alvh.no-ip.org
Whole thread Raw
In response to Re: pgsql: Fix a couple of bugs in MultiXactId freezing  (Noah Misch <noah@leadboat.com>)
Responses Re: pgsql: Fix a couple of bugs in MultiXactId freezing
List pgsql-hackers
Noah Misch wrote:
> On Tue, Dec 03, 2013 at 07:26:38PM +0100, Andres Freund wrote:
> > On 2013-12-03 13:14:38 -0500, Noah Misch wrote:
> > > On Tue, Dec 03, 2013 at 04:37:58PM +0100, Andres Freund wrote:
> > > > I currently don't see fixing the errorneous freezing of lockers (not the
> > > > updater though) without changing the wal format or synchronously waiting
> > > > for all lockers to end. Which both see like a no-go?
> > > 
> > > Not fixing it at all is the real no-go.  We'd take both of those undesirables
> > > before just tolerating the lost locks in 9.3.
> > 
> > I think it's changing the wal format then.
> 
> I'd rather have an readily-verifiable fix that changes WAL format than a
> tricky fix that avoids doing so.  So, modulo not having seen the change, +1.

I've committed a patch which hopefully fixes the problem using this
approach.  Thanks, Noah, for noticing the issue, and thanks, Andres, for
collaboration in getting the code in the right state.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services



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