On 2014-04-14 15:45:45 +0100, Simon Riggs wrote: > On 13 April 2014 16:44, Andres Freund <and...@2ndquadrant.com> wrote: > > On 2014-04-12 17:40:34 -0400, Robert Haas wrote: > >> On Fri, Apr 11, 2014 at 10:28 AM, Andres Freund <and...@2ndquadrant.com> > >> wrote: > >> > VACUUM sometimes waits synchronously for a cleanup lock on a heap > >> > page. Sometimes for a long time. Without reporting it externally. > >> > Rather confusing ;). > >> > > >> > Since we only take cleanup locks around vacuum, how about we report at > >> > least in pgstat that we're waiting? At the moment, there's really no way > >> > to know if that's what's happening. > >> > >> That seems like a pretty good idea to me. > > > > What I am not sure about is how... It's trivial to set > > pg_stat_activity.waiting = true, but without a corresponding description > > what the backend is waiting for it's not exactly obvious what's > > happening. I think that's better than nothing, but maybe somebody has a > > glorious better idea. > > pg_stat_activity.waiting = true
Yes. That's what I suggested above. The patch for it is trivial, but: Currently - I think - everything that sets waiting = true, also has contents in pg_locks. Not sure if it will confuse users if that's not the case anymore. > Easy to set the ps message also That actually makes it considerably more expensive since we'd need to save the old string somewhere. I am not sure it will be relevant, but it's not as easy a sell as just setting a single boolean. Greetings, Andres Freund -- 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
