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

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;

Greetings,

Andres Freund

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