Re: VACUUM and read-mostly tables

"Ian Westmacott" <ianw(at)intellivid(dot)com> writes:
> The problem is that we are writing rows every 1/15 second, 24x7. There
> is no down time. I'm wondering if there is any way to avoid vacuuming
> the old tables over and over. The documentation seems to indicate that
> a full vacuum is needed to avoid XID wrap-around. Can vacuum freeze
> help me?

VACUUM FULL isn't really relevant. VACUUM FREEZE on a particular table
should "fix" that table permanently, as long as you don't make any more
changes to it. Keep in mind though that you still have to vacuum the
system catalogs often enough to avoid wraparound in them. The real risk
here is in overlooking any one table. You should probably use some kind
of automated vacuum driver ... have you looked at pg_autovacuum?

I believe Fujitsu is looking into what it'd take to make a variant
Postgres with 64-bit XIDs. This'd probably imply also expanding CIDs,
OIDs, and some other things, so the space penalty is not to be sneezed
at ... but it might be worth it for installations like yours.

regards, tom lane