Oracle-L: RE: Win2000/8.1.7.3.0/SQL

From: John Kanagaraj <john.kanagaraj_at_hds.com>
Date: Tue, 20 Aug 2002 12:23:31 -0800
Message-ID: <F001.004BA5B7.20020820122331@fatcity.com>

Mike,

> Ok...this is strange. The optimizer_mode is set to RULE, but if
> I put a RULE hint into the SQL it runs OK. I tried increasing

This is almost clearly a case of the CBO being forced for whatever reason. And there are many :( Cut and paste from the Fine Manual (Oracle 8i Designing and Tuning for Performance). See the last 'Note:' :)

The Optimizer 4-19
Features that Require the CBO
The use of any of the following features requires the use of the CBO: n Partitioned tables
n Index-organized tables
n Reverse key indexes
n Function-based indexes
n SAMPLE clauses in a SELECT statement
n Parallel execution and parallel DML
n Star transformations
n Star joins
n Extensible optimizer
n Query rewrite (materialized views)
n Progress meter
n Hash joins
n Bitmap indexes
n Partition views (release 7.3)
Note: Even if the parameter OPTIMIZER_MODE is set to RULE, the use of these features enables the CBO.

John Kanagaraj
Oracle Applications DBA
DBSoft Inc
(W): 408-970-7002

Disappointments are inevitable in Life, but discouragement is optional. You decide!

The opinions and statements above are entirely my own and not those of my employer or clients ** -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: John Kanagaraj INET: john.kanagaraj_at_hds.com

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