Re: pgsql: Fix a couple of bugs in MultiXactId freezing

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/
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