Re: oracle can ignore hints
- From: "K Gopalakrishnan" <kaygopal@xxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 5 Mar 2004 10:52:06 +0530
Hi,
I think it just ignores the hints specified by the duhevelopers. The
recursive SQLs which
are hinted (some RULE !!) will not be ignored.
Regards,
Gopal
----- Original Message -----
From: "Khedr, Waleed" <Waleed.Khedr@xxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Friday, March 05, 2004 10:49 AM
Subject: RE: oracle can ignore hints
> This would be nice if it causes Oracle itself to ignore its own hints
> specified in the kernel that take care of execution plans, PQ, etc :)
>
> Waleed
>
> -----Original Message-----
> From: K Gopalakrishnan [mailto:kaygopal@xxxxxxxxx]
> Sent: Thu 3/4/2004 11:41 PM
> To: oracle-l@xxxxxxxxxxxxx
> Cc:
> Subject: Re: oracle can ignore hints
>
>
>
> Jonathan:
>
> It is version dependent. I am sure you like that.
> BTW starting from 10g you can ask oracle to ignore the hints by setting an
> underscore parameter.
>
> Regards,
> Gopal
>
> ----- Original Message -----
> From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
> To: <oracle-l@xxxxxxxxxxxxx>
> Sent: Friday, March 05, 2004 3:09 AM
> Subject: Re: oracle can ignore hints
>
>
> >
> > No.
> >
> > The intent is that they should be absolute directives;
> > but there are conditions that put hints out of context,
> > which means they become irrelevant.
> >
> > If it can happen at all, it can be hinted.
> >
> > Regards
> >
> > Jonathan Lewis
> > http://www.jlcomp.demon.co.uk
> <https://access0.fidelity.com/,DanaInfo=www.jlcomp.demon.co.uk+>
> >
> > The Co-operative Oracle Users' FAQ
> > http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
<https://access0.fidelity.com/faq/ind_faq.html,DanaInfo=www.jlcomp.demon.co.
> uk+>
> >
> > March 2004 Hotsos Symposium - The Burden of Proof
> > Dynamic Sampling - an investigation
> > March 2004 Charlotte OUG (www.cltoug.org) CBO Tutorial
> > April 2004 Iceland
> > June 2004 UK - Optimising Oracle Seminar
> >
> >
> > ----- Original Message -----
> > From: "April Wells" <AWells@xxxxxxxxxx>
> > To: <oracle-l@xxxxxxxxxxxxx>
> > Sent: Thursday, March 04, 2004 7:44 PM
> > Subject: RE: oracle can ignore hints
> >
> >
> > :
> > : Yep, they are 'friendly suggestions' that the CBO can simply choose to
> > : ignore if it thinks it knows better than you.
> > :
> > : We have one query that we have hinted, we have computed statistics, we
> > have
> > : built histograms, we have jumped through hoops... the only way to
force
> it
> > : to use an index is to Never analyze that index and to hope, then, that
> the
> > : CBO makes the right assumptions.
> > :
> >
> >
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