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Re: Locally Managed Tablespaces - any cons???

From: Robert Fazio <rfazio_at_home.com.nospam>
Date: Fri, 10 Aug 2001 21:57:49 GMT
Message-ID: <xNYc7.91101$EP6.22111132@news1.rdc2.pa.home.com>

From what I have read. Oracle doesn't allow for the system tablespace to be LM. Infact, if you read the docs on dbms_space_admin, you will see that it won't even allow system to be converted, but the say they will support it in the future. The other two RBS and TEMP probably shouldn't be either. TEMP for example is already handled differently if set to type temporary, plus you want the ablity to change the extent management at a later time, if you choose LM, then you can't. RBS has the same issues.

Other than some early bugs related to the LM tablespaces, I do agree.

--
Robert Fazio
Senior Technical Analyst
dbabob_at_yahoo.com

"Howard J. Rogers" <howardjr_at_www.com> wrote in message
news:3b745321_at_usenet.per.paradox.net.au...

>
> "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 - 16:57:49 CDT

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