On Fri, 2003-08-22 at 10:45, Tom Lane wrote:
> Jan Wieck <JanWieck@Yahoo.com> writes:
> Right. One big question mark in my mind about these "partial vacuum"
> proposals is whether they'd still allow adequate FSM information to be
> maintained. If VACUUM isn't looking at most of the pages, there's no
> very good way to acquire info about where there's free space.
Well, pg_autovacuum really needs to be looking at the FSM anyway. It
could look at the FSM, and choose to to do a vacuum normal when there
the amount of FSM data becomes inadequate. Of course I'm not sure how
you would differentiate a busy table with "inadequate" FSM data and an
inactive table that doesn't even register in the FSM. Perhaps you would
still need to consult the stats system.