Matthew T. O'Connor wrote: > This still seems ambiguous to me, how would I handle a maintenance > window of Weekends from Friday at 8PM though Monday morning at 6AM? My > guess from what said is: > mon dom dow starttime endtime > null null 6 20:00 null > null null 1 null 06:00 > > So how do we know to vacuum on Saturday or Sunday? I think clearly > defined intervals with explicit start and stop times is cleaner.
mon dom dow start end null null 5 20:00 23:59:59 null null 6 00:00 23:59:59 null null 7 00:00 23:59:59 null null 1 00:00 06:00 (1 = monday, 5 = friday) Now I'm starting to wonder what will happen between 23:59:59 of day X and 00:00:00 of day (X+1) ... Maybe what we should do is not specify an end time, but a duration as an interval: month int dom int dow int start time duration interval That way you can specify the above as mon dom dow start duration null null 5 20:00 (4 hours + 2 days + 6 hours) Now, if a DST boundary happens to fall in that interval you'll be an hour short, or it'll last an hour too long :-) > >I had two ideas: one was to make pg_autovacuum hold default config for > >all tables not mentioned in any group, so sites which are OK with 8.2's > >representation can still use it. The other idea was to remove it and > >replace it with this mechanism. > > Probably best to just get rid of it. GUC variables hold the defaults > and if we create a default interval / group, it will also have defaults. Yeah, maybe. > >My idea was to assign each table, or maybe each group, to a queue, and > >then have as much workers as there are queues. So you could put them > >all in a single queue and it would mean there can be at most one vacuum > >running at any time. Or you could put each group in a queue, and then > >there could be as many workers as there are groups. Or you could mix. > > > >And also there would be a "autovac concurrency limit", which would be > >a GUC var saying how many vacuums to have at any time. > > Hmm... this seems like queue is nearly a synonym for group. Can't we > just add num_workers property to table groups? That seems to accomplish > the same thing. And yes, a GUC variable to limits the total number of > concurrent autovacuums is probably a good idea. queue = group of groups. But I'm not sure about this at all, which is why I took it away from the proposal. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org
