Re: OPTIMIZER_MODE ???

From: Neil Chandler <oracle_at_tchp2.tcamuk.stratus.com>
Date: 1998/01/19
Message-ID: <slrn6c6u4u.r18.oracle@tchp2.tcamuk.stratus.com>#1/1

In article <69urt0$ms7$1_at_gte2.gte.net>, "Pei L. Ku" wrote:

The actual options for the OPTIMIZER_MODE are:

RULE
CHOOSE
FIRST_ROWS (cost based - index weighted) ALL_ROWS (cost based - table-scan weighted)

If you use choose, and there are statistics in the tables, you will use the ALL_ROWS version of the CBO.

regs

Neil Chandler

>This is a 'bug' in Oracle documentation -- 'COST' is not a valid value.
>The reality, as you have found out, is this:
>
>RULE = rule-based optimizer
>CHOOSE = cost-based optimizer
>
>Pei
>
>Nabil Courdy <moab_at_emirates.net.ae> wrote in article
><01bd2438$35c7d8a0$4b0ee5c3_at_msdusr>...
>>
>> I am unable to set OPTIMIZER_MODE = COST under
>> 7.3 on NT 4.0. It only accepts RULE or CHOOSE.
>> I read somewhere in the Advanced Tuning book that is
>> is best to set it at either COST or RULE. Any idea?
>>
>> Nabil Courdy
>> moab_at_emirates.net.ae
>> ==================
>> --
>>
>>
Received on Mon Jan 19 1998 - 00:00:00 CST