RE: The best CPU usage measurement in Oracle: BUFFER_GETS or CPU_TIME?
- From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 21 Jun 2004 09:55:38 -0500
Jurijs,
If, in step 1, you've discovered that either (a) 'CPU service' or (b)
competition for CPU service (what the book calls 'unaccounted for' time) =
is
the major source of your response time consumption, then the right step =
2 is
to identify the top consumers of CPU_TIME during the problem time =
interval.
The direct statistic, not an indirect or incomplete one like BUFFER_GETS =
for
exactly the reasons you have described.
This is true /if/ CPU_TIME is a reliable statistic in Oracle. I have not
investigated whether it is, but I do expect that it is.
Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
* Nullius in verba *
Upcoming events:
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Boston
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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx =
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of J.Velikanovs@xxxxxxxx
Sent: Monday, June 21, 2004 3:05 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: The best CPU usage measurement in Oracle: BUFFER_GETS or
CPU_TIME?
>> My point is: may be now the better measure is CPU_TIME? I show in=20
previous
>> posting situation then CPU_TIME figure is 10 times accurate then=20
BUFFER_GETS.
>> Can you show me contrariwise situation?=20
>>=20
>> [Cary Millsap] No, I think you're actually on the best path to the=20
solution.
Lets me ask contrariwise question:
Are there situations when using statspack report (if using) or other=20
instance wide performance tool the better way to see TOP SQL-s is sort =
by=20
BUFFER_GETS not CPU_TIME?
Jurijs
Additional info from previous postings:
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
1. Activity=20
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
NAME VALUE
----------------------------------------------------------------=20
session logical reads 23002
CPU used by this session 137
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
2. Activity=20
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
NAME VALUE
----------------------------------------------------------------=20
session logical reads 23006
CPU used by this session 1422
I.
session logical reads=20
Action 1 =3D Action 2
II.
CPU used by this session
Action 1 * 10 =3D Action 2
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