RE: Tkprof ouput -- Query on times waited/max waited/total waited

  • From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Thu, 5 Feb 2004 08:27:14 -0600

Responses in-line.


Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of
k.sriramkumar@xxxxxxxxxxxxxxxxxx
Sent: Thursday, February 05, 2004 4:39 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Tkprof ouput -- Query on times waited/max waited/total waited
Importance: High

Hi Gurus,

        I was analyzing the output of 10046 event of a single session.
Myself and my fellow coleage differ in the interpretation of the output
statistics.

Question 1
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

The output Reads

Elapsed times include waiting on following events:
  Event waited on                             Times   Max. Wait  Total
Waited
  ----------------------------------------   Waited  ----------
------------
  SQL*Net message to client                       6        0.00
0.00
  SQL*Net message from client                     5      132.69
142.99


My Understanding of this output is=20

        Times waited -- Number of times this event has waited. Here the
user might have entered 7 statements hence it says
number of times waited as 6

[Cary Millsap] Close. It means that there were six occasions when the db
server was awaiting input from the client. It probably means that there
were about six dbcalls, but even this can vary because of call bundling,
pre-fetching, and so on.

        Max Waited -- Maximum duration of wait (Out of the 6 times it
has waited)

[Cary Millsap] Yes. You can confirm this by checking the raw trace data.

        Total Waited -- Total Waiting time ( sigma of 6 wait times )

[Cary Millsap] Yes. Again, this is easy to confirm by examining the
input data to tkprof.

Pls confirm whether my understanding is correct.


Question 2
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

Say I turn on the SQL tracing at 12.00 and the session is idle till 1.00
and a single SQL statement is executed at 1.00.

Now if I analyze the ouput.

My undestanding is that, this 1 hour would be accounted in the  "SQL*Net
message from client" . Is my understanding correct??

[Cary Millsap] Yes. This is what I call in Jeff's and my book
"collection error." You probably don't need to optimize that hour, so
you shouldn't collect timing data for that hour.


Best Regards

Sriram Kumar











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