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

From: Riyaj Shamsudeen <riyaj.shamsudeen_at_gmail.com>
Date: Thu, 22 May 2008 20:28:32 -0500
Message-ID: <203315c10805221828h4e23b56cvab787b80f43a9e12@mail.gmail.com>


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
>
> -------------------------------------------------------------
>
> **************** CAUTION - Disclaimer *****************
> This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely
> for the use of the addressee(s). If you are not the intended recipient, please
> notify the sender by e-mail and delete the original message. Further, you are not
> to copy, disclose, or distribute this e-mail or its contents to any other person and
> any such actions are unlawful. This e-mail may contain viruses. Infosys has taken
> every reasonable precaution to minimize this risk, but is not liable for any damage
> you may sustain as a result of any virus in this e-mail. You should carry out your
> own virus checks before opening the e-mail or attachment. Infosys reserves the
> right to monitor and review the content of all messages sent to or from this e-mail
> address. Messages sent to or from this e-mail address may be stored on the
> Infosys e-mail system.
> ***INFOSYS******** End of Disclaimer ********INFOSYS***
>
>

-- 
Cheers
Riyaj Shamsudeen
The Pythian Group - www.pythian.com
orainternals.wordpress.com

--
http://www.freelists.org/webpage/oracle-l
Received on Thu May 22 2008 - 20:28:32 CDT

Original text of this message