Re: cost based optimizer

Chris Xia wrote:
>
> In article <DM2GFI.8Gw_at_iquest.net>, parbha_at_iquest.net (New Age) writes:
> > In ORACLE Ver 7.02, Which is best : Cost based or Rule based query. I
> > have a rule based statement which executes faster than cost based
> > query. Has ORACLE really implemented Cost based sql query or they
> > fooling around ?
> >
> > Has anyone faced this problem. I may be wrong in my above statements.
> >
> > prabha
> > prabha_at_lilly.com (office)
> > parbha_at_iquest.net (home)
> >
>
> About cost based optimizer, there is one thing you need to do to make it smarter.
> that is : you need to run analyze on the tables you are querying. lacking of the
> statistics could hamper the ability of cost-based optimizer.
>
> The rule of thumbs is (according to the book ORACLE
> performance tuning by Peter Corrigan and Mark Gurry): if you have a query which
> is fine-tuned for the rule-based, then give it a hint, otherwise, use cost-based
> optimizer. ( and don't forget to run analyze ).
>
> Chris

I presume Peter Corrigan is on the net somewhere. He lives in Melbourne, Australia. Perhaps he even reads this newsgroup.

I hear he was a thorn in Oracle's side for quite some time until they rewrote the optimizer for version 7.1. I would suggest, Prabba, that if at all possible you upgrade from 7.0 to something much later.

Joan. Received on Thu Feb 08 1996 - 00:00:00 CET