Re: How to tune this query ...

How to tune this query ...from metalink on RBO desupport.

http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_id=189702.1&p_database_id=NOT

"The RBO will still exist in Oracle10i, but will be an unsupported feature and will be removed in a future release."

Desupport of the Rule-Based Optimizer

The rule-based optimizer (RBO) will no longer be supported when Oracle9i is de-supported. The release after Oracle9i (referred to in this article as Oracle10i) will only support the cost-based optimizer (CBO). Hence Oracle9i Release 2 is the last release to support the RBO. Partners and customers should certify their applications with the CBO before that time. The CBO has been Oracle's primary optimization method for many years now, and most major independant software vendors use the CBO by choice. Our surveys indicate that over 80% of customers are using the CBO with Oracle8i, and this number is expected to increase with Oracle9i. For more information on the CBO please refer to the Query Optimization in Oracle9i white paper which can be found at: http://otn.oracle.com/products/bi/pdf/o9i_optimization_twp.pdf

What is being Desupported?

The RBO is Oracle's legacy optimizer originating from Oracle Version 6 and earlier. The RBO is being desupported in Oracle10i. The RBO will still exist in Oracle10i, but will be an unsupported feature and will be removed in a future release. No code changes will be made to the RBO code and no bug fixes will be provided. The RBO was superseded in Oracle7 by the CBO and has continued to be available for backwards compatibility. Oracle Oracle10i will support only one optimizer, and all applications running on that release should use that optimizer.

Versions Affected

Support for the RBO will be removed in Oracle10i. The last release that supports the rule-based optimizer will be Oracle9i Release 2.

• Original Message ----- From: Cary Millsap To: Multiple recipients of list ORACLE-L Sent: Friday, November 08, 2002 10:48 PM Subject: RE: How to tune this query ...

  Watch out, though. The RULE hint probably goes away in 10i (my guess, nothing official).

  Cary Millsap
  Hotsos Enterprises, Ltd.
  http://www.hotsos.com

  Upcoming events:

• Hotsos Clinic, Dec 9-11 Honolulu
• 2003 Hotsos Symposium on OracleŽ System Performance, Feb 9-12 Dallas
• Jonathan Lewis' Optimising Oracle, Nov 19-21 Dallas

  -----Original Message-----
  From: root_at_fatcity.com [mailto:root_at_fatcity.com] On Behalf Of Jamadagni, Rajendra   Sent: Friday, November 08, 2002 4:59 PM   To: Multiple recipients of list ORACLE-L   Subject: RE: How to tune this query ...

  This works nice .... Barbara Baker also hinted me that a good old RULE hint fixes the problem.

  Thank you Waleed and Barbara ...

  Raj

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