RE: CBO irregularity

P3 of "db file scattered read" waits will show the size of the
multiblock read actually performed.

 

Thanks and Regards,

Satheesh Babu.S

Bangalore.

 

  _____  

From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Naveen, Nahata
(IE10)
Sent: Tuesday, June 08, 2004 10:49 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: CBO irregularity

 

        -          Make sure that your system statistics reasonably
represent the operational characteristics of your system. For example,
if your system really averages 3.7 blocks per multi-block read, then CBO
will make dumb decisions about whether to do full-table scans on systems
were db_file_multiblock_read_count=128.
         
        [Naveen Nahata] Can you please elaborate on how I can find, how
many blocks my system reads on an average per oracle multi-block read
request?

         

           Regards 
        Naveen

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