Re:

<mark(dot)dingee(at)cox(dot)net> writes:
> I had an odd situation occur this morning with PGSQL 7.4 run on Red Hat Enterprise 4 (update 3) and could really use some wisdom.

> ... Single postmaster running.
> ... vacuum full is run every night as part of a cron job
> ... At start, data files consume about 28 GB
> ... This morning I dropped the database and reloaded from current backup
> ... New instance consumes about 6 GB

> I can only assume that the database was not compacted, but I thought vacuum full performed that function along with tuple maintenance. Can anyone expound on the problem and suggest a solution other than dropping and reloading the database?

The evidence is mostly gone now, but what I'd suggest is waiting a while
to see if it bloats again, and if so finding out exactly *where* the
bloat is. Make some notes now about the sizes of your tables and
indexes, and see what's getting larger.

My guess offhand is that the problem is index bloat. VACUUM FULL not
only doesn't help much with that, it tends to make it worse. If the
database size is supposed to be fairly stable, you'd probably be better
off with a maintenance regime that doesn't use VACUUM FULL but just
plain VACUUM. Make sure your FSM settings are high enough.

regards, tom lane