Re: DB CPU in Time Model
- From: Venkat Krish <venkat.lear@xxxxxxxxx>
- To: Niall Litchfield <niall.litchfield@xxxxxxxxx>
- Date: Tue, 16 Aug 2011 08:59:30 -0400
Thanks Niall.. I understand CPU seconds is depedent on # of cpus..
Usually if the cpus were consumed by SQLs (hash-joins,sorts, or I/Os),
shouldn't the sql elapsed time also be approximately equal or more than DB
CPU % (83% in this case).. I am lost on why sql elapsed time reports only
46% and there is nothing else (pl/sql elapsed time, parse time) that is
significantly higher..
I guess , my question is.. can there be "DB CPU" slice thats not part of
sql,pl/sql & parsing ?
Thanks
Venkat
On Tue, Aug 16, 2011 at 1:53 AM, Niall Litchfield <
niall.litchfield@xxxxxxxxx> wrote:
> On a machine with more than one 'CPU' you can spend more than 1 second on
> cpu time for each second of elapsed time.
>
>
> On Mon, Aug 15, 2011 at 9:08 PM, Venkat Krish <venkat.lear@xxxxxxxxx>wrote:
>
>> Hi -
>> This is just a curious question that popped up my mind by looking at
>> someone's AWR.. I dont have access to database and wont be able to run any
>> related query or anything.
>>
>> The TimeModel statistics have been pasted here:
>> http://pastebin.com/YZ7SRX0M
>>
>>
>> The question is related to "DB CPU" metric ..
>>
>> Here is what I know or my thought process.. please correct me, if I am
>> missing anything or incorrectly ruling out
>>
>> -- the SQL elapsed time accounts only to less than 50% (if there was a
>> culprit sql or API, it should hv been counted against this.)
>> -- parsing is near zero (so its not parsing cpu)
>> -- there could have been no PL/SQL (looping with dbms_lock.sleep or
>> anything similar) because PLSQL exec time is almost zero
>>
>>
>> what could be causing this DB CPU.. ?? if the db is spending 83% on total
>> db time cpu but doesnt correspond to sql or plsql elapsed time, is it a good
>> or bad indicator?
>>
>> Thanks in advance,
>> Venkat
>>
>> PS: DB version : 11.2.0.2 running on Solaris
>>
>>
>>
>
>
> --
> Niall Litchfield
> Oracle DBA
> http://www.orawin.info
>
Other related posts:
