On Fri, Sep 4, 2009 at 2:48 PM, Tom Lane<t...@sss.pgh.pa.us> wrote: > Josh Berkus <j...@agliodbs.com> writes: >>>> I have a client who uses temp tables heavily, hundreds of thousands of >>>> creates >>>> and drops per day. They also have long running queries. The only >>>> thing that >>>> keeps catalog bloat somewhat in check is vacuum full on bloated catalogs >>>> a few times a day. With > >> Actually, this is a good point ... if we dropped VACUUM FULL, we'd need >> to also be able to call CLUSTER (or VACUUM REWRITE) on the system catalogs. > > I don't think I believe the claim above that vacuum full is actually > necessary. Reasonably aggressive regular vacuuming ought to do it. > > We used to have a bug that caused row deletions during backend shutdown > to not get reported to the stats collector; which had the effect that > dead catalog entries for temp tables didn't get counted, and so autovac > didn't hit the catalogs often enough, and so you'd get bloat in exactly > this scenario. I suspect the claim that manual vacuum full is necessary > is based on obsolete experience from before that bug got stomped. > It's hardly an ideal solution anyway given what an exclusive lock on > pg_class will do to the rest of the system --- and a cluster-like > cleanup won't be any better about that.
I'm confused. Are you saying that pg_class will never get bloated, so we don't need a way to debloat it? I realize that with HOT bloat is much less of a problem than it used to be, but surely it's not altogether impossible... ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
