Simon Riggs <si...@2ndquadrant.com> writes: > On 11 October 2012 18:22, Tom Lane <t...@sss.pgh.pa.us> wrote: >> If it worked, I might be amenable to that, but it doesn't. You can't >> trigger taking a new snapshot off whether we waited for a lock; that >> still has race conditions, just ones that are not so trivial to >> demonstrate manually. (The other transaction might have committed >> microseconds before you reach the point of waiting for the lock.)
> So where's the race? Same example as before, except that the exclusive-lock-holding transaction commits (and releases its lock) between the time that the other transaction takes its parse/plan snapshot and the time that it takes AccessShare lock on the table. 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