Michael Riess wrote:
> Hi,
>
> yes, some heavily used tables contain approx. 90% free space after a
> week. I'll try to increase FSM even more, but I think that I will
> still have to run a full vacuum every week. Prior to 8.1 I was using
> 7.4 and ran a full vacuum every day, so the autovacuum has helped a
> lot.
>
> But actually I never understood why the database system slows down at
> all when there is much unused space in the files. Are the unused pages
> cached by the system, or is there another reason for the impact on the
> performance?
The reason is that the system needs to LOOK at the pages/tuples to see
if the tuples
are dead or not.
So, the number of dead tuples impacts the scans.
LER
>
> Mike
--
Larry Rosenman
Database Support Engineer
PERVASIVE SOFTWARE. INC.
12365B RIATA TRACE PKWY
3015
AUSTIN TX 78727-6531
Tel: 512.231.6173
Fax: 512.231.6597
Email: Larry.Rosenman@pervasive.com
Web: www.pervasive.com
