RE: autotrace issue

Isn't it normal that the plan changes with the actual value in the where clause. That is what the optimizer does. You can use a bind variable instead of that literal and see what the plan is.

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Sanjay Madan Sent: Friday, October 14, 2005 2:01 PM
To: oracle-l_at_freelists.org
Subject: autotrace issue

Hi ,

Oracle 9.2.0.5 on AIX
Partitioned table ( list) ~ 10 mil rows in all distibuted almost equally across 5 partitions
field1 ( used in the query) is not the PK.

My autotrace ( traceonly explain) output for a particular query changes with the actual value of the input parameter.

select .......
where ...........
and field1 = 123456

autotrace output shows an Index range scan whereas

select .......
where ...........
and field1 = 1234561

autotrace output shows a full table scan (not the exact input values) ...

I have tried values
-both within and outside the field lengths of field1
-values actually existing in the table
-values NOT existing in the table.

It seems to be happening randomly. For most values it shows an index range scan.
For others (fewer) it shows a full table scan.

Any hints as to what could be happening or where I should look to solve the problem ?

Thanks

sanjay

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http://www.freelists.org/webpage/oracle-l Received on Fri Oct 14 2005 - 06:39:22 CDT