RE: CPU Time calculation in AWR Reports
- From: Tanel Poder <tanel.poder.003@xxxxxxx>
- To: lfcerri@xxxxxxxxx, oracle-l@xxxxxxxxxxxxx
- Date: Fri, 02 Nov 2007 01:10:30 +0800
Well you can trace the awrrpt run...
I suspect (but don't know for sure) that AWR uses DBA_HIST_SYS_TIME_MODEL
for its CPU info... V$SYS_TIME_MODEL CPU values can differ from V$SYSSTAT
ones...
SQL> select
2 a.value/1000000 time_model_seconds,
3 b.value/10000 sysstat_seconds,
4 a.value/1000000 - b.value/10000 missing_seconds
5 from
6 v$sys_time_model a,
7 v$sysstat b
8 where
9 a.stat_name = 'DB CPU'
10 and b.name = 'CPU used by this session'
11 /
TIME_MODEL_SECONDS SYSSTAT_SECONDS MISSING_SECONDS
------------------ --------------- ---------------
126.997282 4.6276 122.369682
--
Regards,
Tanel Poder
http://blog.tanelpoder.com
> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx
> [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Luis
> Fernando Cerri
> Sent: Thursday, November 01, 2007 23:20
> To: oracle-l@xxxxxxxxxxxxx
> Subject: CPU Time calculation in AWR Reports
>
> Hello, list.
>
> At Statspack age, 'CPU Time' value in section 'Top 5 Timed
> Events' was calculated as the difference of 'CPU used by this
> session' values between two snapshots:
>
> select 'CPU' , (e.value-b.value)/100 time
> from stats$sysstat b, stats$sysstat e
> where e.snap_id = :v_eid
> and b.snap_id = :v_bid
> and e.name = 'CPU used
> by this session'
> and b.name = 'CPU used
> by this session';
>
>
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