Re: Yet another "why is my index not used" question

From: Jonathan Lewis <>
Date: Wed, 28 Jan 2009 08:09:01 -0000
Message-ID: <>

"Michael Austin" <> wrote in message news:lBKfl.16314$
> Jonathan, Based on his WHERE Clause - no amount of fiddling is going to
> fix his problem until he gives the optimizer something other than "is not
> null" to work with- it is still going to do a FTS.


I think you're looking at the query that Dimitre used to generate an alternative value for the clustering_factor. This uses "is not null" clauses against every column in the index he is analyzing to ensure that Oracle can legal use the index-only access path that's needed.


Jonathan Lewis

Author: Cost Based Oracle: Fundamentals

The Co-operative Oracle Users' FAQ
Received on Wed Jan 28 2009 - 02:09:01 CST

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