Re: Oracle Hint Behavior

From: Anurag Varma <avoracle_at_gmail.com>
Date: Wed, 30 Jan 2008 07:27:00 -0800 (PST)
Message-ID: <27862c6b-063a-41af-acef-97e962e2863d@q21g2000hsa.googlegroups.com>


On Jan 30, 9:28 am, "Dereck L. Dietz" <diet..._at_ameritech.net> wrote:
> Oracle 10.2.0.3.0
> Windows 2003 Server
>
> What is the behavior of hints in Oracle 10g? I knew that prior to 10g
> Oracle would treat them as only "suggestions" but I thought in 10g they
> would be mostly followed.
>
> We have a query which is doing a full table scan even with hints being used
> to try to get it to use an index. I can see why it would choose a full
> table scan considering the percentage of the table being returned but I'd
> like to be able to explain why the hint is being ignored now.
>
> Thanks.

Even prior to 10g, if a hint was valid, oracle would follow it. I believe
Jonathan Lewis explained in greater detail on when a hint might not be followed.

example:
http://jonathanlewis.wordpress.com/2006/11/11/what-is-a-hint/

Anurag Received on Wed Jan 30 2008 - 09:27:00 CST

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