Alvaro Herrera <[EMAIL PROTECTED]> writes: > - pg_statistic is completely ignored.
... pg_statistic still needs vacuuming, surely. It's only ANALYZE that you can/should skip for it. > - The postmaster's main loop sleeps Min(60, autovacuum_naptime), in > order to be able to pick naptimes smaller than 60 seconds. In order > not to make the loop a busy-wait, I forced a minimum of 1 to that GUC > var. Hmm, I wonder whether the minimum shouldn't be 10. Or even 60. > - Now that we have a real Xid wraparound check, we could go back to > having any table with no stat entry ignored, which was the original > coding. There's no danger of wraparound, and there'd be no work done > to a table that doesn't have any activity. Agreed. > We have to consider what > happens at stat reset -- AFAICS there's no problem, because as soon as > the table sees some activity, it will be picked up by pgstat. > However, it would be bad if stats are reset right after some heavy > activity on a table. Maybe the only thing we need is documentation. What's the use-case for having the stat reset feature at all? > - datallowcon is still ignored. Now it's safe to do so, because we have > a real Xid wraparound check. Changing it requires extending the > pg_database flat-file (should be fairly easy). I think this is all right, as long as a database that shows no stats traffic is only connected to when it needs to be vacuumed for XID wrap prevention purposes. > - There are stat messages emitted for a database-wide vacuum, just like > any other. This means that all tables in the database would end up in > pgstat; and also all databases, including those with datallowconn = false. > This may not be good. I'm not sure what exactly to do about it. Do > we want to disallow such stats? Disable message sending (or > collecting) in some circumstances? Needs thought... regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match