Re: oracle can ignore hints

From: K Gopalakrishnan <kaygopal_at_yahoo.com>
Date: Fri, 5 Mar 2004 10:11:31 +0530
Message-ID: <004001c4026c$260a4fb0$0200010a@idc.oracle.com>

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_at_jlcomp.demon.co.uk> To: <oracle-l_at_freelists.org> 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
>
> The Co-operative Oracle Users' FAQ
> http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
> 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_at_csedge.com>
> To: <oracle-l_at_freelists.org>
> 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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Received on Thu Mar 04 2004 - 22:42:28 CST