Simon Riggs <si...@2ndquadrant.com> writes: > On 11 October 2012 20:43, Tom Lane <t...@sss.pgh.pa.us> wrote: >> Robert Haas <robertmh...@gmail.com> writes: >>> So we have to take the snapshot before you begin execution, but it >>> seems that to avoid surprising behavior we also have to take it after >>> acquiring locks. And it looks like locking is intertwined with a >>> bunch of other parse analysis tasks that might require a snapshot to >>> have been taken first. Whee.
>> Yeah. I think that a good solution to this would involve guaranteeing >> that the execution snapshot is not taken until we have all locks that >> are going to be taken on the tables. Which is likely to involve a fair >> amount of refactoring, though I admit I've not looked at details. >> >> In any case, it's a mistake to think about this in isolation. If we're >> going to do something about redefining SnapshotNow to avoid its race >> conditions, that's going to move the goalposts quite a lot. >> >> Anyway, my feeling about it is that I don't want 9.2 to have an >> intermediate behavior between the historical one and whatever we end up >> designing to satisfy these concerns. That's why I'm pressing for >> reversion and not a band-aid fix in 9.2. I certainly hope we can do >> better going forward, but this is not looking like whatever we come up >> with would be sane to back-patch. > Agreed, please revert. We have to do something about this one way or another before we can ship 9.2.2. Is the consensus to revert this patch: http://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=d573e239f03506920938bf0be56c868d9c3416da and if so, who's going to do the deed? regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
