Home » RDBMS Server » Server Administration » Verify CBO (Oracle 10.2.0.4.0,SunOS)
Verify CBO [message #555345] Wed, 23 May 2012 05:32 Go to next message
Jack14
Messages: 497
Registered: December 2011
Location: INDIA
Senior Member
Hi,

How to find out the database is using Cost based analyzer?

Currently database is set to ALL_ROWS.

SQL> show parameter optimizer_mode

NAME                                 TYPE        VALUE
------------------------------------ ----------- -----------
optimizer_mode                       string      ALL_ROWS
SQL>
SQL>


Thank you
Re: Verify CBO [message #555354 is a reply to message #555345] Wed, 23 May 2012 06:28 Go to previous messageGo to next message
cookiemonster
Messages: 11287
Registered: September 2008
Location: Rainy Manchester
Senior Member
All_rows means CBO. Unless it's set to RULE it's using the CBO.
You can check by running explain plan on a query - if you get cost figures it's using the CBO. The RBO doesn't understand cost.
Re: Verify CBO [message #555355 is a reply to message #555345] Wed, 23 May 2012 06:28 Go to previous messageGo to next message
Michel Cadot
Messages: 60063
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
If it is not RULE then it is CBO.

Regards
Michel
Re: Verify CBO [message #555356 is a reply to message #555355] Wed, 23 May 2012 06:46 Go to previous message
Jack14
Messages: 497
Registered: December 2011
Location: INDIA
Senior Member
Thank you Michel and Cookie for answers.
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