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RE: Surprising parameters for direct path read in 100046 trace

From: Fedock, John (KAM.RHQ) <John.Fedock_at_us.kline.com>
Date: Tue, 7 Mar 2006 14:27:26 -0500
Message-ID: <5042FDC675779848A113F70D54F587490E3BB82C@KAMRICEXCLUS.us.kline.com>


That is how I would read it as well. Let me know what you find out. Time for a TAR?

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

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]On Behalf Of Chris Dunscombe Sent: Tuesday, March 07, 2006 5:15 AM
To: oracle-l_at_freelists.org
Subject: Surprising parameters for direct path read in 100046 trace

Hi,

I've traced a long running piece of SQL and observed the following in the trace file (only a small sample):

WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 4 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 4 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 4 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 4 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 5 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 4 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 4 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 4 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 4 p1=202 p2=641040 p3=1
WAIT #3: nam='direct path read' ela= 4 p1=202 p2=641041 p3=1
WAIT #3: nam='direct path read' ela= 3 p1=202 p2=641040 p3=1
.................

My understanding is that p1 is the filenum#, p2 the block# and p3 the block count. So my question is why is Oracle continually re-reading the same 2 blocks?

Oracle version 9.2.0.4 64 bit on Solaris. Filenum# 202 is an Oracle temp file. The SQL was in the middle of a sort merge at the time.

Thanks,

Chris Dunscombe

www.christallize.com

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http://www.freelists.org/webpage/oracle-l Received on Tue Mar 07 2006 - 13:27:26 CST

Original text of this message

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