Re: "db file async I/O submit" wait event : 11gR2

  • From: Taral Desai <taral.desai@xxxxxxxxx>
  • To: aditya.yadavalli@xxxxxxxxx
  • Date: Wed, 28 Jul 2010 14:10:08 -0500

Well the real culprit would be log file switch (checkpoint incomplete)

there is possibility that your i/o bandwidth is very low. You can try
increasing logfile size to see if this can give some time to write to
logfiles.

On Wed, Jul 28, 2010 at 1:18 PM, Yadavalli Aditya <
aditya.yadavalli@xxxxxxxxx> wrote:

> Hi All,
>
> I am seeing poor performance with one of the 11gR2 instances, and when
> i ran statspack reports for the time period , i am seeing "db file
> async I/O submit" wait event on the top hitting almost 56%. I have
> checked metalink as well as google, did not get any information.
> Please share your experiences if any one has seen this before. here is
> the snapshot (numbers are galbled, please excuse!)
>
>
> Top 5 Timed Events                                                    Avg
> %Total
> ~~~~~~~~~~~~~~~~~~                                                   wait
> Call
> Event                                            Waits    Time (s)   (ms)
> Time
> ----------------------------------------- ------------ ----------- ------
> ------
> db file async I/O submit                            13          53   4068
> 56.2
> log file switch (checkpoint incomplete)              4          27   6808
> 28.9
> CPU time                                                         6
>   6.2
> log file parallel write                          1,452           5      4
>  5.8
> control file parallel write                         65           1     20
>  1.4
>
> Thank you,
> Aditya
> --
> //www.freelists.org/webpage/oracle-l
>
>
>


-- 
Thanks & Regards,
Taral Desai

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