RE: Index clustering factor
- From: "Stephens, Chris" <chris_stephens@xxxxxxxxxxxx>
- To: <Orysia.Husak@xxxxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 9 Jan 2008 14:37:08 -0600
I'd first try hinting the index and see if that results in less db work.
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Orysia Husak
Sent: Tuesday, January 08, 2008 6:45 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Index clustering factor
On our 10.2.0.3 database, we have a very simple query that is not using
the index that we expected and is instead doing a full tablescan. The
clustering factor of this index is very high. Have any of you
encountered a similar problem? How have you solved it?
Have any of you used the technique described in the book Cost-Based
Oracle Fundamentals by Jonathan Lewis to adjust the clustering factor of
an index using the sys_op_countchg() function?
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.
The clustering factor of the index is : 1089825
The table is located in an ASSM type tablespace and the table stats:
NUM_ROWS BLOCKS
---------- ----------
1976721 31517
I'd appreciate your suggestions ...... or experiences using the
sys_op_countchg() function.
Thank you,
Orysia
Orysia Husak
Sr. Oracle DBA - Classroom Applications Hosting
University of Phoenix/ Apollo Group, Inc.
Office: 602-557-6934
Mobile: 602-377-8586
orysia.husak@xxxxxxxxxxxxx
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