On Mon, Aug 23, 2010 at 16:38, Tom Lane <t...@sss.pgh.pa.us> wrote: > Magnus Hagander <mag...@hagander.net> writes: >> On Mon, Aug 23, 2010 at 16:28, Greg Smith <g...@2ndquadrant.com> wrote: >>> What I actually want here is for the time that the last table autovacuum >>> started, adding to the finish time currently exposed by pg_stat_user_tables. > >> Now, that would be quite useful. That'd require another stats message, >> since we don't send anything on autovacuum start, but I don't think >> the overhead of that is anything we need to worry about - in >> comparison to an actual vacuum... > > No, you wouldn't really need an extra message, you could just send both > start and finish times in the completion message. I'm not sure that > having last start time update before last end time would be a good idea > anyway.
Hmm, good point. We'd just need an extra field in that message. > But in any case it's true that an extra message wouldn't be a > significant cost. What I'd be more concerned about is the stats table > bloat from adding yet another per-table field. That could be a lot of > space on an installation with lots of tables. > >> We could also store last_autovacuum_vacuum_duration - is that better >> or worse than start and end time? > > No, I think you want to know the actual time not only the duration. Well, you could calculate one from the other - especially if one takes less size, per your comment above. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers