Re: Index clustering factor

From: Jared Still <>
Date: Wed, 9 Jan 2008 15:22:29 -0800
Message-ID: <>

On Jan 9, 2008 1:54 PM, Orysia Husak <> wrote:

> When I generate an explain plan manually, the appropriate index is used.
> When I view the sql running through OEM, I see the execution plan is a
> full tablescan. Since the clustering factor for this index is very high,
> my assumption is that the index isn't being selected due to the high
> clustering factor.

Cluster factor should not come into play if only 1 or two blocks need to be read.

It seems as if you may have been unlucky, as in the SQL in the cache was parsed
with values that required an FTS due to data skew.

One of the optimizer experts is sure to chime in here soon.

Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist

Received on Wed Jan 09 2008 - 17:22:29 CST

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