Others have answered most of this; I'll add a summary...
- You can tell whether timed_statistics was activated by checking your
raw trace data. If you see any non-zero value for a tim field, it was
on.
- The Oracle kernel gets its CPU time statistics from calls to the
getrusage system call (times on HP-UX). The getrusage function gets the
information from the OS process table. Except on Solaris with microstate
accounting activated, the OS process table gets its CPU statistics by
sampling at 0.01-second intervals. Of course, data sampled at
0.01-second intervals are accurate only to +/-0.01 seconds per sample.
For events that execute on the order of microseconds, odds are that
there will be significant error. But summing these values over a large
sample (like in a big trace file) still makes sense.
Full details (pictures, etc.) about all this are in the book "Optimizing
Oracle Performance."
Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
* Nullius in verba *
Upcoming events:
- Performance Diagnosis 101: 3/23 Park City, 4/6 Seattle
- Hotsos Symposium 2004: March 7-10 Dallas
- Visit www.hotsos.com for schedule details...
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of ryan.gaffuri_at_cox.net
Sent: Monday, March 08, 2004 1:50 PM
To: oracle-l_at_freelists.org
Subject: tkprof and parse count?
Below is a simple tkprof output. Why is my parse count = 4? if there is
no CPU time used? I take this to mean, I did not incur a hard parse? How
come the 'count' goes up? I can't find this in the docs on metalink.
select 2
from
dual
call count cpu elapsed disk query current
rows
------- ------ -------- ---------- ---------- ---------- ----------
Parse 4 0.00 0.00 0 0 0
0
Execute 4 0.00 0.00 0 0 0
0
Fetch 8 0.00 0.00 0 12 0
4
------- ------ -------- ---------- ---------- ---------- ----------
total 16 0.00 0.00 0 12 0
4
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Received on Thu Mar 11 2004 - 09:32:56 CST
