RE: Index clustering factor

From: Brady, Mark <Mark.Brady_at_Constellation.Com>
Date: Thu, 10 Jan 2008 14:37:09 -0500
Message-ID: <72AB68B424526641A8514835270C2EB5033B7930@EXM-OMF-21.Ceg.Corp.Net>


Jonathan, can you expand upon the question, "what does OEM tell you about the run-time predicates?" a bit.

Where in OEM would I look if wanted to answer that question?

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jonathan Lewis Sent: Thursday, January 10, 2008 2:10 AM To: oracle-l_at_freelists.org
Subject: Re: Index clustering factor

The optimizer cannot ignore the index hint for that query. Therefore the hint is illegal.

The first thing to check is whether you have a column coercion issue. What are the types of the columns and of the input variables - and what does OEM tell you about the run-time predicates ?

Regards

Jonathan Lewis
http://jonathanlewis.wordpress.com

Author: Cost Based Oracle: Fundamentals
http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

  • Original Message ----- From: "Orysia Husak" <Orysia.Husak_at_apollogrp.edu> Subject: RE: Index clustering factor

The statement is expected to fetch only 1 or 2 rows. The default Oracle gather_stats generates a histogram size auto.

We've provided an index hint in the SQL and Oracle sill ignores the index.
>
>Our query is :
>
>Select * from tableA where fielda=:A and fieldb=:B
>
>We have an index on tableA (fielda, fieldb), but Oracle isn't using the
index.
>

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Received on Thu Jan 10 2008 - 13:37:09 CST

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