Re: when rebuild IOT ?

"DA Morgan" <damorgan_at_psoug.org> a écrit dans le message de news:1170372675.84902_at_bubbleator.drizzle.com...
> Eric wrote:
> > I'm on 9.2.0.5. I have noticed that some IOTs where taking as much 2 to
4
> > times space as they should. Are we supposed to rebuild IOTs, and what
are
> > pros & cons about that ?
> >
> > Thanks,
> >
> > Eric
>
> How are you determining the size they are supposed to be?
>
> And ;-) how do you get enough free time to care?
> --
> Daniel A. Morgan
> University of Washington
> damorgan_at_x.washington.edu
> (replace x with u to respond)
> Puget Sound Oracle Users Group
> www.psoug.org

Surprising answer for someone working in a university, loosing time for such answer :-).

Not interested in finding that sometimes your 10Gb database could be only 3 Gb ? so I believe that impacts performance. Besides, Oracle only says in documentation that IOT can be rebuilt online, but does not tell when this should be. Regarding sizing, there are simple formulas, like sum(column_length) ... and look before/after in the correct view after ALTER TABLE ... MOVE to find out that it really reduced by 2 to 4 (in my case) the size of IOT.

Now, for someone really doing DBA job on Oracle, when do you decide to rebuilt IOT, and what are pros & cons about that ?

Cheers,

Eric Received on Fri Feb 02 2007 - 00:54:33 CST