Re: How to revert to DMTS ?
From: Randolf Geist <mahrah_at_web.de>
Date: Fri, 1 Oct 2010 05:05:33 -0700 (PDT)
Message-ID: <865dd3da-e07d-4cba-916c-a28118718cff_at_i21g2000yqg.googlegroups.com>
On Sep 30, 9:21 pm, "Gerard H. Pille" <g..._at_skynet.be> wrote:
> Mladen Gogala wrote:
> > On Thu, 30 Sep 2010 19:43:41 +0200, Gerard H. Pille wrote:
>
> >> Hallo,
>
> >> for performance reasons I need a couple of dictionary managed
> >> tablespaces
>
> > What, exactly, is the performance problem that the dictionary managed
> > tablespaces would solve?
>
> Excessive undo on intensive deletes and inserts in indexes, multiple sessions inserting (DMTS +
> freelists) and slower full table scans.
Date: Fri, 1 Oct 2010 05:05:33 -0700 (PDT)
Message-ID: <865dd3da-e07d-4cba-916c-a28118718cff_at_i21g2000yqg.googlegroups.com>
On Sep 30, 9:21 pm, "Gerard H. Pille" <g..._at_skynet.be> wrote:
> Mladen Gogala wrote:
> > On Thu, 30 Sep 2010 19:43:41 +0200, Gerard H. Pille wrote:
>
> >> Hallo,
>
> >> for performance reasons I need a couple of dictionary managed
> >> tablespaces
>
> > What, exactly, is the performance problem that the dictionary managed
> > tablespaces would solve?
>
> Excessive undo on intensive deletes and inserts in indexes, multiple sessions inserting (DMTS +
> freelists) and slower full table scans.
Do you by any chance mix here ASSM vs. MSSM with LMT vs. DMT (I like all these acronyms by the way) ? What you describe above applies to some extent (in certain scenarios) to tablespaces using Automatic Segment Space Management (ASSM) instead of MSSM (Manual Segment Space Management using freelists / freelist groups instead of ASSM bitmaps). What makes you think that using DMT instead of LMT addresses these issues?
Regards,
Randolf
Oracle related stuff blog:
http://oracle-randolf.blogspot.com/
Co-author of the "OakTable Expert Oracle Practices" book: http://www.apress.com/book/view/1430226684 http://www.amazon.com/Expert-Oracle-Practices-Database-Administration/dp/1430226684 Received on Fri Oct 01 2010 - 07:05:33 CDT