[sorry to everyone if that mail arrives multiple times, but i had
some odd problems with my mail gateway yesterday...]
On Wed, Mar 01, 2006 at 12:41:01PM -0500, Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
> > Tom Lane wrote:
> >> How does an optimistic FSM entry avoid the need to run vacuum?
>
> > It ensures that all freed tuples are already in the FSM.
>
> That has nothing to do with it, because the space isn't actually free
> for re-use until vacuum deletes the tuple.
>
But couldn't such an opportunistic approach be used for
another lightweight VACUUM mode in such a way, that VACUUM could
look at a special "Hot Spot" queue, which represents potential
candidates for freeing? Let's call it a 2-phase VACUUM....this would
avoid a constant long running VACUUM run on big tables, e.g. when
tuples gets updated (or deleted) frequently. Just an idea...
Bernd