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Re: How Can I force SQL to use a specific plan?

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Fri, 14 Sep 2001 21:13:07 +0100
Message-ID: <1000498400.12273.0.nnrp-13.9e984b29@news.demon.co.uk>

I disagree - bear in mind that Oracle now implements stored outlines for plan stability.

A stored outline is a list of hints to apply to an SQL statement at run-time.

Whilst hints may have been unstable, or 'only hints' in earlier versions of Oracle, I believe that it is now necessary that hints should be obeyed IF Oracle is sufficiently constrained that it cannot find an alternative path that permits it to ignore some of your hints.

This requirement makes it harder to make Oracle follow a required path, but given sufficient hints, you can ALWAYS (bar one bug I know of) force Oracle 8.1+ to follow the path you want.

--
Jonathan Lewis
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Markus Stuhlpfarrer wrote in message <3BA1D182.A1651892_at_hollomey.com>...

>yes, you can try this, but it is possible that it doesn't work
>as the word says, this are hints and not rules
>you cannot really force oracle to do it this way
>
Received on Fri Sep 14 2001 - 15:13:07 CDT

Original text of this message

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