Re: Awr waits over 100%

From: Marcus Mönnig <mm_at_marcusmoennig.de>
Date: Wed, 28 Sep 2011 17:35:03 +0200
Message-ID: <CAFuw4vkJs9WsPeGaM_Yd=9qB1uuDo9zwAtzWcjqx90Wqz299bA_at_mail.gmail.com>



Hi Kenneth,

the time for log buffer space and log file parallel write might partly be included in log file sync, especially when there are frequent commits, so there is some double counting taking place.

Tony Hasler explained this in his 3 blog posts here: http://tonyhasler.wordpress.com/2011/07/24/log-file-sync-and-log-file-parallel-write-part-1/

Cheers,
Marcus

2011/9/28 Kenneth Naim <kennethnaim_at_gmail.com>:
> I pulled an awr this morning for a period and the top wait events add up to
> almost 200%. I was curious if anyone saw this before. I've seen it slightly
> over 100% that I wrote off for rounding but never saw it so high. I'm
> addressing the actual wait events so no issues there.
>
>
>
>
>
>
> Top 5 Timed Events
>
>
> Event
>
> Waits
>
> Time(s)
>
> Avg Wait(ms)
>
> % Total Call Time
>
> Wait Class
>
>
> log file sync
>
> 356,514
>
> 2,521
>
> 7
>
> 84.5
>
> Commit
>
>
> log file parallel write
>
> 358,641
>
> 1,967
>
> 5
>
> 65.9
>
> System I/O
>
>
> CPU time
>
>
>
> 1,192
>
>
>
> 39.9
>
>
>
>
> db file parallel write
>
> 23,911
>
> 364
>
> 15
>
> 12.2
>
> System I/O
>
>
> log buffer space
>
> 135
>
> 58
>
> 427
>
> 1.9
>
> Configuration
>
>
>
> Thanks,
>
> ken
>
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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Received on Wed Sep 28 2011 - 10:35:03 CDT

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