Re: Locally Managed Tablespaces - any cons???

"Kenneth Koenraadt" <plovmand_at_hotmail.com> wrote in message news:3b7197c5.7098447_at_news.mobilixnet.dk...
>
> On Tue, 7 Aug 2001 21:20:37 -0600, "Ron Gardiner"
> <rongardiner_at_powersurfr.com> wrote:
>
> >New for 8i (I believe) is locally managed tablespaces...
> >
> >From what I've read, sounds like there is no reason NOT to use them. Can
> >they be used for all types of TS?... rollback segs, temporary, how about
> >system itself?
> >
> >Any feedback would be appreciated!
> >
> >
> >
> Hi Ron,
>
> You cannot create a locally managed SYSTEM tablespace on database
> creation. But you can convert it to LM later with a supplied package.
>
> The SYSTEM tablespace and the tablespaces for rollback segments must
> have the same extent management type, so if you convert the SYSTEM
> Tablespace to LMT, rememer to convert your RBS tablespace(s) to LMT as
> well.
>

This is just not true.

Firstly, whilst you may be able to convert SYSTEM into a LMT, it's strongly advised not to. You may have noticed that SYSTEM also has 50% PCTINCREASE, which is generally bad, and is autoextensible, which is also usually considered not terribly efficient... but the point is, SYSTEM breaks all the rules, and is best left to do so. LMT/DMT is just another example.

Secondly, you appear to suggest that if SYSTEM is DMT, you must have DMT rollback segment tablespace. Absolutely not true. Provided there is one non-system rollback segment created (and brought online), you can create a LMT rollback tablespace, and create (and online) one LMT'd rollback segment... after which, the original DMT'd rollback segment can be dropped, and all others created without a problem. And all of that can be done perfectly well with a SYSTEM tablespace that is merrily chugging a way as dictionary-managed.

Incidentally, the SYSTEM tablespace in 9i is still dictionary managed, and there is still no provision for creating it Locally Managed... yet another indication that locally managed SYSTEM tablespace is not advised, nor necessary.

Regards
HJR
> Regards,
> Kenneth Koenraadt
> Systems Consultant
> Oracle DBA
> plovmand@<no-spam>hotmail.com
Received on Fri Aug 10 2001 - 16:37:05 CDT