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

Andres Freund wrote:
> On 2013-12-03 19:55:40 -0300, Alvaro Herrera wrote:
> > I added a new isolation spec to test this specific case, and noticed
> > something that seems curious to me when that test is run in REPEATABLE
> > READ mode: when the UPDATE is aborted, the concurrent FOR UPDATE gets a
> > "can't serialize due to concurrent update", but when the UPDATE is
> > committed, FOR UPDATE works fine. Shouldn't it happen pretty much
> > exactly the other way around?
>
> That's 247c76a989097f1b4ab6fae898f24e75aa27fc1b . Specifically the
> DidCommit() branch in test_lockmode_for_conflict(). You forgot something
> akin to
> /* locker has finished, all good to go */
> if (!ISUPDATE_from_mxstatus(status))
> return HeapTupleMayBeUpdated;

So I did. Here are two patches, one to fix this issue, and the other to
fix the issue above. I intend to apply these two to 9.3 and master, and
then apply your freeze fix on top (which I'm cleaning up a bit -- will
resend later.)

--
Álvaro Herrera http://www.2ndQuadrant.com/
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