RE: "control file sequential read" wait during RAC Benchmark ?

  • From: Hemant K Chitale <hkchital@xxxxxxxxxxxxxx>
  • To: "VIVEK_SHARMA" <VIVEK_SHARMA@xxxxxxxxxxx>, "oracle-l" <oracle-l@xxxxxxxxxxxxx>
  • Date: Wed, 28 Feb 2007 00:49:21 +0800

12seconds CPU time [of which 5seconds went to statspack.snap()]
and 7 seconds "control file sequential read"  are not significant
fractions of the elapsed time of 7minutes.
[your server has 8 CPUs on this node so the total available CPU time was 56minutes
and only 12seconds were consumed by Oracle processes ?]
Your server and database were actually idle.
Get some real load on the system and re-run StatsPack.


At 11:12 PM Tuesday, VIVEK_SHARMA wrote:
Thanks Hemant

Replies embedded below , Prefixed by -> & in Violet.

Sending you the respective Statspack in an Offline e-mail too.


-----Original Message-----
From: Hemant K Chitale [mailto:hkchital@xxxxxxxxxxxxxx]
Sent: Tuesday, February 27, 2007 8:31 PM
To: VIVEK_SHARMA; oracle-l@xxxxxxxxxxxxx
Subject: Re: "control file sequential read" wait during RAC Benchmark ?

Total wait time for "control file sequential read" is 7 seconds.
Is that significant ?  Was the StatsPack snapshot for a duration of
10 minutes ? 1 hour ?

-> Period between the Statspack Snapshots = 6.97 minutes

Snapshot       Snap Id     Snap Time      Sessions Curs/Sess Comment
~~~~~~~~ ---------- ------------------ -------- --------- -------------------
Begin Snap:         27 23-Feb-07 17:53:38       70      16.1
  End Snap:         28 23-Feb-07 18:00:36       80      18.3
   Elapsed:                6.97 (mins)

Why do you think "control file sequential read" waits would be tempered by
"transaction be grouped logically so that transactions hit different
data blocks" ?

-> That is a Question & I do NOT know if "grouping transactions" has any impact on the "control file sequential read" wait.
-> Seek your Advice on this.

At 09:07 PM Tuesday, VIVEK_SHARMA wrote:
>Qs 2) Should Transactions be grouped Logically so that Transactions
>Hit different Data Blocks on the 2 Nodes?
>Top 5 Timed
>Events                                                    Avg %Total
>wait   Call
>Event                                            Waits    Time
>(s)   (ms)   Time
>----------------------------------------- ------------ -----------
>------ ------
>time                                                        12          43.6
>control file sequential
>read                    21,969           7      0   25.4

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Hemant K Chitale


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