Re: CPU rounding

From: Gerry Miller <gerry_at_millerandbowman.com>
Date: Fri, 18 Nov 2011 07:23:40 +1000
Message-ID: <4EC57B5C.3050504_at_millerandbowman.com>

 Thanks to those who replied. I have been assuming all along that it was a local problem, perhaps something to do with the OS configuration, but now it seems to be something to do with the OS version or is an "undocumented feature" in 11.2.
This is more of a problem than it may appear as it substantially overestimates the CPU contribution to total resource usage, as this excerpt from an AWR report shows:
Top 5 Timed Foreground Events

---

                                                           Avg
                                                          wait   % DB
Event                                 Waits     Time(s)   (ms)   time Wait

Class

------------------------------ ------------ ----------- ------ ------
----------
DB CPU                                                2         140.4
log file sync                            52           0      2    4.9 Commit
direct path read                        207           0      0     .7 User
I/O
SQL*Net break/reset to client            40           0      0     .3
Applicatio
Disk file operations I/O                 29           0      0     .2 User

I/O

I don't think management would be impressed with either me or Oracle if I told them that CPU accounted for 140% of total database resource usage duringa period.

Andrew, regarding your suggestion that I try MOS, I submitted an SR on this on September 21st. The first analyst assured me on two occasions that the values were expressed in microseconds because it said so in the Oracle documentation. He also tested the query on his 11.2.0.2 environment and did not strike the problem but I have since found that it does not occur on Windows installations and he didn't say what OS he was on. After a few exchanges I asked for another analyst on September 28th and after a few "Anyone there?" updates from me I was appointed one on October 13th. On October 18th he asked me to upload some output files, which I did and have not heard from him since. I had the SR escalated to Severity 3 on November 14th and have received a reply from yet another analyst asking me to upload an RDA, which I will do. In summary, I did go through MOS and am quite unimpressed. I was going to say singularly unimpressed but I have been unimpressed with Oracle Support more than once.

Thanks again

Gerry

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Received on Thu Nov 17 2011 - 15:23:40 CST