RE: wait time is huge compared with cpu time

From: Khemmanivanh, Somckit <somckit.khemmanivanh_at_weyerhaeuser.com>
Date: Fri, 21 Jul 2006 09:48:55 -0700
Message-ID: <65C0D8935651CB4D96E97CEFAC5A12B9022F1838@wafedixm10.corp.weyer.pri>

Could maybe be a by product of when transactions completed. Remember that the recording is made when the transaction completes...so timing wise a long running transaction could have just completed when you began the snap?

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of amonte Sent: Friday, July 21, 2006 9:35 AM
To: oracle-l_at_freelists.org
Subject: wait time is huge compared with cpu time

I have a HP-UX Server running Oracle 8.1.7.4, there are 6 CPUs.

I have a statspack report which shows this (2 hours interval)

                Snap Id     Snap Time      Sessions
                ------- ------------------ --------
 Begin Snap:        143 20-Jul-06 02:31:02      453
   End Snap:        167 20-Jul-06 04:31:06      453 
    Elapsed:                 120.07 (mins)


Top 5 Wait Events 
~~~~~~~~~~~~~~~~~                                             Wait     %
Total
Event                                               Waits  Time (cs)

Wt Time

-------------------------------------------- ------------ ------------
-------
latch free                                      3,573,965    6,945,555
99.25
log file sync                                     122,691       30,316


.43

log file parallel write                           146,604       18,685


.27

SQL*Net more data to client                       522,539        1,762


.03

db file sequential read                            10,923          534

.01

Statistic                                    Total   per Second    per

Trans

--------------------------------- ---------------- ------------
------------
CPU used by this session                 2,990,059        415.1
27.6
CPU used when call started               2,423,510        336.4

22.4

I was wondering how can we get over 69000 seconds waits in 2 hours with 6 CPUs? That is much larger than

3600seconds * 6CPUs * 2hours

TIA Alex

--
http://www.freelists.org/webpage/oracle-l

Received on Fri Jul 21 2006 - 11:48:55 CDT