RE: What is the purpose of DBMS_RESOURCE_MANAGER.CALIBRATE_IO?

  • From: "Goulet, Richard" <Richard.Goulet@xxxxxxxxxxx>
  • To: "wljohnson@xxxxxx" <wljohnson@xxxxxx>, ORACLE-L <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 21 Nov 2011 13:37:58 +0000

Bill,

        The 11g Optimizer is supposed to take system statistics into account.

Richard Goulet
Senior Oracle DBA/Na Team Leader


-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of Johnson, William L (TEIS)
Sent: Monday, November 21, 2011 8:20 AM
To: ORACLE-L
Subject: What is the purpose of DBMS_RESOURCE_MANAGER.CALIBRATE_IO?

We have an open service request with SAP where we are working on an Oracle 
performance issue related to Oracle 11.2.0.1 and securefiles.
SAP is asking us to run the calibrate_io process.  Does this have any purpose 
internal to the database other than showing information about io stats?  Does 
it affect the optimizer based on io response?

I have found lots of links that explain how to run the calibrate_io process for 
Resource Manager and how to look at the results - but none that seem to take 
the next step to explain why you are doing this or whether or not the optimizer 
will take this information into consideration when doing an explain plan.

Does anyone have experience with this process?  Is it just simply a tool to 
measure io performance like Orion and no other purpose in life - so to speak?

Thanks!
Bill Johnson

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