Robert Haas <robertmh...@gmail.com> writes: > On Fri, Feb 12, 2016 at 6:22 PM, Andres Freund <and...@anarazel.de> wrote: >> I wonder if we shouldn't just expose a 'which pid is process X waiting >> for' API, implemented serverside. That's generally really useful, and >> looks like it's actually going to be less complicated than that >> query... And it's surely going to be faster.
> If PID 12000 and PID 13000 hold AccessShareLock on relation foo, and > PID 14000 awaits AccessExclusiveLock on that relation, what does the > function return when 14000 is passed as an argument? Yeah. In general, it's not that easy to say that A is waiting specifically on B --- there may be multiple blockers and/or multiple ways it could get released. isolationtester's query is not really correct IMO. It's okay as long as nothing else besides autovacuum is taking locks, but I wouldn't want to try to make it work in a general purpose environment. regards, tom lane -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers