Re: RULE vs COST based optimiser
Date: 1996/04/16
Message-ID: <4l12hv$ajt_at_altrade.nijmegen.inter.nl.net>#1/1
grant_at_towersoft.com.au (Fuzzy) wrote:
>Any ideas on this problem would be much appreciated.
>A 750 Meg Oracle database is split roughly between 500 Meg of data and
>250 Meg of indexes. However, the db is set to rule-based optimising.
>I think it should be set to cost-based (otherwise serious resources
>are being wasted on maintaining indexes, statistics, etc), but the
>customer is dubious. Any ideas on what kind of improvement (if any)
>will be made by switching to cost-based?
It depends. I have an customer who was using cost-based optimizing. This would cause good response on most parts of our application, but absolutly terrible performance on several screens. After switching to rule based optimizing, the performance on the few screens improved significantly (from 75 mins down to 13 seconds!) and also solved several other problems that we could not reproduce. On the other hand, several other screens now have an poorer response.
I know this is not very helpfull for your problem.
>Ciao
>Fuzzy
>:-)
Bye, Jan Paul
SQL Systems B.V.
Customer Support.
Received on Tue Apr 16 1996 - 00:00:00 CEST