Re: oracle can ignore hints

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Thu, 4 Mar 2004 21:39:37 -0000
Message-ID: <00cb01c40231$334b9160$7002a8c0@Primary>

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 - 16:48:35 CST