Heikki Linnakangas <hlinnakan...@vmware.com> writes: > On 21.03.2013 05:36, Tom Lane wrote: >>> The API that comes to mind is (name subject to bikeshedding) >>> pg_blocking_pids(pid int) returns int[]
> How about inverting the function into: > pg_pid_blocked_by(pid int) returns int > It would take as argument a pid, and return the pid of the process that > is blocking the given process. That would feel more natural to me. Hm, I'm not sure that's uniquely defined. In the case I mentioned before (A has AccessShare, B is blocked waiting for AccessExclusive, C wants AccessShare and is queued behind B), which of A and B do you think is blocking C? Whichever answer you choose could be the wrong one for isolationtester: I think it needs to consider that C is blocked if *either* A or B is part of its set of test processes. So that's why I thought an array (or set) result including both A and B would be appropriate. AFAICT, what you're proposing isn't the "inverse" of what I said, it's the same direction but you're assuming there's only one blocking process. 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