RE: Optimizer Plan's Cost

From: Lex de Haan <lex.de.haan_at_naturaljoin.nl>
Date: Tue, 26 Oct 2004 11:16:53 +0200
Message-ID: <JFEEIGBIDOCCDALDIPLNOEDPCKAA.lex.de.haan@naturaljoin.nl>

the CBO costs are cumulative. so in your case the total estimated cost is 24.

Kind regards,
Lex.

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-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]On Behalf Of fahd mirza Sent: Tuesday, October 26, 2004 10:10
To: Active DBA
Subject: Optimizer Plan's Cost

Hi Listers,

      I have one doubt regarding optimizer plan. would u please rectify them.
Lets say I have a query like this

select * from foo where foo100=:b1 order by foodate;

The plan might be like this

Operation                                            Step#            Cost
Select Statement                                   4                    24
    Sort (order by)                                    3
24
        foo table access                             2                   22
          fooidx index (range scan)              1                     1

Now what would be the cost of this plan. would it be the aggregate of all four operations that is 24+24+22+1=71 or would it be just of first operation i.e. 24 or what? Please clarify this. thanks regards,
Fahd

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http://www.freelists.org/webpage/oracle-l Received on Tue Oct 26 2004 - 04:12:41 CDT