On Mon, Nov 26, 2012 at 10:55 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > 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?
I was assuming you were going to do it. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
