RE: CBO irregularity

From: <Satheesh.Babu_at_iflexsolutions.com>
Date: Tue, 8 Jun 2004 11:17:05 +0530
Message-ID: <10898BE7CA96D611988B000802255AAF069B1B2A@fmgrt.rt.i-flex.com>

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

Thanks and Regards,

Satheesh Babu.S

Bangalore.  

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From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Naveen, Nahata (IE10)
Sent: Tuesday, June 08, 2004 10:49 AM
To: oracle-l_at_freelists.org
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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Received on Tue Jun 08 2004 - 00:40:05 CDT