Re: High "log file sync" wait in HP-UX Benchmark ?

Vivek
  Can you please send me the statspack report, please?   log file sync waits can occur for many reasons, and most common reasons are poor write bandwidth for log writer, frequent commits, or CPU starvation. Statspack report will usually spell out the issue.

Cheers
Riyaj

On Wed, May 21, 2008 at 3:00 PM, VIVEK_SHARMA <VIVEK_SHARMA_at_infosys.com> wrote:

> Folks
>
>
>
> During a Benchmark, High "log file sync" wait is observed for OLTP
> Transactions
>
>
>
> Qs 1 What is the Solaris "maxphys" equivalent parameter on HP-UX 11.31? ..
> Increasing this had helped.
>
> Qs 2 Will moving the Online Redo logfiles from Mounted Filesystem to RAW
> Devices help? ... This had significantly helped in the Solaris case since
> Oracle was using pwrite() function call to write to redo logfiles on Mounted
> Filesystem , while another function call (forgot which) was used to write to
> redo logfiles after they were moved to RAW Devices.
>
> Qs 3 Since the Entire Set of Hard Disks is on RAID 5, could this be a
> significant cause for High logfile sync wait?
>
> NOTE – Storage Box = HP EVA 600 SAN Storage Box
>
> RAID 5 setup using SAME thereby consuming all of the 24 Hard Disks in the
> Box
>
>
>
> Will provide Statspack Report as needed.
>
>
>
> Cheers & Thanks in Advance
>
>
>
> Vivek
>
>
>
> *P.S. *
>
> *Config:-*
>
> Oracle 10.2.0.3
>
> HP-UX 11.31
>
> Application – Hybrid Banking Product
>
>
>
> *SP Report:-*
>
> Top 5 Timed Events Avg
> %Total
>
> ~~~~~~~~~~~~~~~~~~ wait
> Call
>
> Event Waits Time (s) (ms)
> Time
>
> ----------------------------------------- ------------ ----------- ------
> ------
>
> log file sync 178,131 1,659 9
> 52.0
>
> CPU time 972
> 30.5
>
> log file parallel write 140,197 240
> 2 7.5
>
> cursor: pin S 888,008 147
> 0 4.6
>
> db file sequential read 43,218 77
> 2 2.4
>
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-- 
Cheers
Riyaj Shamsudeen
The Pythian Group - www.pythian.com
orainternals.wordpress.com

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