Re: Vacuum only with 20% old tuples

how about leaving vacuum as is, but extend REINDEX so that it
drops/rebuilds all indices on a TABLE | DATABASE? Or does it do that
now? From reading \h REINDEX, my thought is that it doesn't, but ...

On Tue, 11 Jul 2000, Bruce Momjian wrote:

> > We can't "drop and recreate" without a solution to the relation
> > versioning issue (unless you are prepared to accept a nonfunctional
> > database after a failure partway through index rebuild on a system
> > table). I think we should do this, but it's not all that simple...
> >
> > I do not see what your 20% idea has to do with this, though, nor
> > why it's a good idea. If I've told the thing to vacuum I think
> > it should vacuum. 20% of a big table could be a lot of megabytes,
> > and I don't want some arbitrary decision in the code about whether
> > I can reclaim that space or not.
>
> Well, I think we should do a sequential scan before starting vacuum to
> find the number of expired rows.
>
> Now that we are removing indexes, doing that to remove a few tuples is a
> major waste. The user can not really know if the table is worth
> vacuuming in normal use. They are just going to use the default. Now,
> I think a FORCE option would be good, or the ability to change the 20%
> default.
>
> Remember, commercial db's don't even return unused space if you remove
> all the rows in a table. At least Informix doesn't and I am sure there
> are others. I like vacuum, but let's not make it do major hurtles for
> small gain.
>
> --
> Bruce Momjian | http://candle.pha.pa.us
> pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
> + If your life is a hard drive, | 830 Blythe Avenue
> + Christ can be your backup. | Drexel Hill, Pennsylvania 19026
>

Marc G. Fournier ICQ#7615664 IRC Nick: Scrappy
Systems Administrator @ hub.org
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