On Thu, 2003-10-16 at 10:16, Rod Taylor wrote: > > The vacuum man page says, "FREEZE is not recommnded for routine use". > > That was enough to keep me away. However if vacuum freeze was > > considerably lighter than normal database wide vacuums then there might > > be an advantage to using it. Especially since when pg_autovaccum > > decides it's time to deal with xid wraparound, it does it to all the > > databases, which could a several hours of vacuum on large clusters. > > Each database has it's own last xid. Just because one database is about > to go over the limit doesn't mean they all are. Why don't you treat > each database independently in this regard (then they wouldn't > necessarily all be kicked off at once).
My choice of words above was poor, let me try again. pg_autovacuum does treat each database independently, however assuming that you never manually run vacuum (which is the eventual goal of pg_autovacuum), then database wide vacuums will have never been run on any table in any database, so all databases will approach xid wraparound at the same time. So, pg_autovacuum does deal with them separately, but doesn't make an effort to spread out the vacuums if all / multiple databases happen to need it at the same time. In practice, I don't see this as a big problem right now, but it should still be handled better by pg_autovacuum. ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings
