Re: Cost versus Rule based Optimizer

From: Michiel Ploeger <nospam.Michiel.Ploeger_at_Bluewater-Group.Com>
Date: Wed, 22 Sep 1999 15:17:19 +0200
Message-ID: <7sal68$8ad$1@news1.xs4all.nl>

Once I analyzed all tables of my database and had a huge drop in performance.
I deleted the analyzed information of schema SYS and my performance was better then ever.

Is the app developed for cost based or rule based ? Are there any hints in the SQL?

Michiel

Aamer wrote in message <37E89431.5BA7DBBB_at_hotmail.com>...
>Hi All
>
>On checking the database it was found that the tables and schemas where
>not analysed. So in fact it was using rule based optimisation. We
>immediately analysed all schemas .
> After analysing The buffer hit ratio which was 95% dropped to 84%
>and the sort in disk increased from 0.5% to 15%.
>
>Once we deleted the analysing information it improved the buffer hit
>ratio to 94% and sort on disk to 6% .
>
> Its not understood why when we analysed the buffer hit ration
>dropped.
>
> Aamer_janjua_at_hotmail.com
>
> Thanks
Received on Wed Sep 22 1999 - 08:17:19 CDT