Re: PostgreSQL clustering VS MySQL clustering

On Sat, Jan 22, 2005 at 12:13:00 +0900,
  Tatsuo Ishii <t-ishii@sra.co.jp> wrote:
>
> Probably VACUUM works well for small to medium size tables, but not
> for huge ones. I'm considering about to implement "on the spot
> salvaging dead tuples".

You are probably vacuuming too often. You want to wait until a significant
fraction of a large table is dead tuples before doing a vacuum. If you are
scanning a large table and only marking a few tuples as deleted, you aren't
getting much bang for your buck.