Re: log_buffer
- From: "Zhu,Chao" <zhuchao@xxxxxxxxx>
- To: jhowerton@xxxxxxxxx
- Date: Wed, 21 May 2008 08:22:11 +0800
Each "log file sync" wait event, the timing is about 300ms......
A well tuned system with "log file sync" should be well within 5ms.
how can a system like that does not have "log file sync" and "log buffer
space" wait event and scale well?
To me, obviously the underlying redo log filesystem/disk/raid is having some
bottleneck.
Without fixing the hardware itself, make no sense to fix oracle.
On Tue, May 20, 2008 at 6:04 AM, James Howerton <jhowerton@xxxxxxxxx> wrote:
> DBA's,
>
> What is you're log_buffer set to??? I have a 2 Tb oltp two node RAC
> database on 10.1.0.5 that is showing lots of log file sync waits. My
> current setting is 1.5 Mb. Redo log files are 2Gb each.
>
>
> Top 5 Timed Events
> ~~~~~~~~~~~~~~~~~~ % Total
> Event Waits Time (s) DB Time Wait
> Class
> ------------------------------ ------------ ----------- ---------
> --------------
> log file sync 356,123 113,472 64.41
> Commit
> log buffer space 35,114 26,771 15.20
> Configuration
> buffer busy waits 21,139 13,489 7.66
> Concurrency
> CPU time 7,996 4.54
> gcs drm freeze in enter server 564,623 5,753 3.27
> Other
>
> TIA
> ...JIM...
>
>
> --
> //www.freelists.org/webpage/oracle-l
>
>
>
--
Regards
Zhu Chao
www.cnoug.org
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