On 11/18/2014 10:47 AM, Tom Lane wrote: > Josh Berkus <j...@agliodbs.com> writes: >> Since querying pg_locks can be intrusive due to needing to lock the lock >> partitions, when I'm collecting data about locks I generally put a >> statement_timeout on it. However, I'm noticing that this >> statement_timeout appears to be completely ignored; I've seen this query >> run for up to 10 minutes* when the database is heavily loaded. This it >> seems likely to me that the functions under pg_locks aren't checking for >> interrupts. Anybody checked this already? > > Whether they do or not, I don't think we allow CHECK_FOR_INTERRUPTS to > trigger while holding an LWLock. So this would not be a trivial thing > to fix.
Hmm. So the basic problem is that querying pg_locks itself can make an already bad locking situation worse (I've seen it contribute to a total lockup, which didn't resolve until I terminated the query against pg_locks). I don't see a clear way to make it less dangerous, so I was hoping that at least making it time out made it safer to use. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
