Re: 8.0.3 pg_autovacuum doesn't clear out stats table?

Robin Iddon <robin@edesix.com> writes:
> The tuples and thresholds for the pg_statistic table look like they
> might be the reason it doesn't get vacuumed.  The question is, why does
> the reltuples on the stats table keep climbing until you do a vacuum
> full, at which point they return to (near) zero?  No matter what
> threshold and scale I set, I am not going to get that table vacuumed
> because it's delete/update rate are 0 (it's always inserted to I believe).

Quite incorrect --- if that were so, there would be no dead tuples
for vacuum to remove, hm?  Actually ANALYZE does an
update-or-insert-if-not-present fandango.

I'm sort of mystified by your report.  I can think of several ways that
the system might fail to notice that pg_statistic needs vacuuming, but
none of them seem to actually occur in the current code, and I don't see
any relevant difference in the CVS logs (I admit to being too lazy to
build an exact 8.0.3 version to test --- but 8.0.7 seems fine).

Can you keep an eye on pg_statistic's entry in the pg_stat_all_tables
view for each affected database, and confirm whether the n_tup_upd/
n_tup_del counts are rising over time or not?  That would at least
narrow down the problem a bit.

            regards, tom lane