Hi, On Tuesday, July 24, 2012 07:48:27 PM Robert Haas wrote: > I am running into a lot of customer situations where the customer > reports that "canceling autovacuum task" shows up in the logs, and > it's unclear whether this is happening often enough to matter, and > even more unclear what's causing it. > > Me: So, do you know what table it's getting cancelled on? > Customer: Nope. > Me: Are you running any DDL commands anywhere in the cluster? > Customer: Nope, absolutely none. > Me: Well you've got to be running something somewhere or it wouldn't > be having a lock conflict. > Customer: OK, well I don't know of any. What should I do? > > It would be awfully nice if the process that does the cancelling would > provide the same kind of reporting that we do for a deadlock: the > relevant lock tag, the PID of the process sending the cancel, and the > query string. > > Personally, I'm starting to have a sneaky suspicion that there is > something actually broken here - that is, that there are lock > conflicts involve here other than the obvious one (SHARE UPDATE > EXCLUSIVE on the table) that are allowing autovac to get cancelled > more often than we realize. But whether that's true or not, the > current logging is wholly inadequate. Very, very, very quick guess: The relation extension lock?
> Thoughts? Anybody else have this problem? I have seen spuriously high occurances of that message before, but I never really investigated it. Andres -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers