# calculate % of response time components

• From: SJHussain@xxxxxxxxxxxxxxx
• To: oracle-l@xxxxxxxxxxxxx, oracle-l-bounce@xxxxxxxxxxxxx
• Date: Tue, 21 Sep 2004 16:58:53 +0300
```

Hello Gurus,

In metalink note : 223117.1 - Tuning I/O related waits, I extracted the
following, but, I couldn't understand the calculation made to get the %
result. The extract of the note are as follows:

Top 5 Wait Events

~~~~~~~~~~~~~~~~~
Wait     % Total

Event
Waits  Time (cs)   Wt
Time

------------------------
--------------------
------------
------------ -------

4,232       10,827
52.01

6,105        6,264
30.09

direct path write
1,992        3,268
15.70

control file parallel
write
893          198     .95

db file parallel write
40          131     .63

------------------------
------------------------
-------------

Based on this listing we
may be tempted to
immediately start
looking at the

causes between the
waits and

to try to tune them.
This approach would not
take into account
'Service Time'.

Here is the statistic
that measures 'Service
Time' from the same
report:

Statistic
Total   per Second
per Trans

------------------------
---------
----------------
------------
------------

CPU used by this session
358,806        130.5
12,372.6

Let's do some simple
math from these figures:

'Wait Time' = 10,827 x
100% / 52,01% = 20,817
cs

'Service Time' = 358,806
cs

'Response Time' =
358,806 + 20,817 =
379,623 cs

If we now calculate
percentages for all the
'Response Time'
components:

CPU time
= 94.52%

=  2.85%

=  1.65%

direct path write
=  0.86%

control file parallel
write =  0.05%

db file parallel write
=  0.03%

Could any one tell me, how the calculations are made to get the % of each
wait event in the above?

Best Regards,

Syed Jaffar Hussain
OCP, DBA Consultant
ITD/Systems Department/Database Section
Tel : 01 4042222 x 1020
Mobile : 0506446723
Visit us on www.alfransi.com.sa
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