Reece Hart <reece@in-machina.com> writes:
> On Thu, 2003-11-13 at 10:09, scott.marlowe wrote:
>
> > Do you vacuum full every so often? If not, and if you've been overflowing
> > your fsm, then your tables will just grow without shrinking.
> > Also, index growth could be a problem.
>
>
> Hmm. I didn't realize that I needed to vacuum full as well -- I thought
> vacuum was sufficient for performance gains, and that full reclaimed
> space but didn't result in significant performance gains.
plain Vacuum is sufficient if the amount of free space it finds fits within
the free space map. During normal use with frequent vacuums on a system with
well-tuned fsm parameters that should be true.
However on a big heavily used database where the fsm parameters haven't been
raised from the defaults it's possible that it isn't. And on a table where
large batch updates or deletes have been run it's possible to require a vacuum
full after the batch job creates lots of dead tuples.
--
greg