FreeLists / oracle-l / RE: CPU Time calculation in AWR Reports

[Tanel Poder <tanel.poder.003@xxxxxxx>]

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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