Re: Optimizer

Rule based optimization is obsolete since 7.1. It is not enhanced anymore, so no parallel query, no bitmap indexes, no hints, no nothing. That alone is a reason to forget about it. And yes you can run into wrong query plans because of 'aged' statistics.

Hth,

Sybrand Bakker, Oracle DBA

Jeff Hunter <marist89_at_excite.com> schreef in berichtnieuws 391f5eec_at_defiant.btitelecom.net...
> I thought I read somewhere that Rule-based optimization will be going away
> in future versions... When using cost based optimization, your objects
 need
> to be optimized on a regular basis.
>
> RL <mark_at_mark-it.demon.co.uk> wrote in message
> news:958301705.11737.0.nnrp-14.9e9864e7_at_news.demon.co.uk...
> > I appreciate this is probably a huge topic, but can anyone point
> > me in the direction of information about the Oracle optimizer.
> > In particular, what should the optimizer rule be
> > set to (CHOOSE, RULE etc). If the optimizer is using cost
> > based optimization, is it necessary to analyze tables regularly or
> > can it be run once. Does the cost based optimizer always give better
> > results that the rule based optimizer or are there too many variables
> > to decide this.
> >
> > Are there are good tools to help with optimization, (where to add
> > indexes etc), I found tkprof output very cryptic.
> >
> > Many thanks
> >
> >
> >
>
>
Received on Mon May 15 2000 - 00:00:00 CDT