Re: log file sync event

As you're on 10.2, look at the commit_write init param, or the new options for the SQL COMMIT command,
it may be scary, but it is worth a look at.

rgds

On 6/8/06, Alex Gorbachev <gorbyx_at_gmail.com> wrote:
>
> To reduce log file sync you need to reduce number and size of IOs per
> physical device used for redo logs and remove all possible contention
> (i.e. dedicate disks).
>
> Reduce number and size of IOs per physical device:
> - add more devices
> - reduce frequency of commits
> - check you log_buffer if it's not too smal and gets filled to 1/3 too
> often - usually not the case with OLTP anyway.
> - reduce amount of redo (don't update when not required - like columns
> with the same values and rows that can be skipped).
> - "do less work" on application - you would be surprised how much can
> be saved and optimized there.
> I would look on these points from bottom up.
>
> Removing contention - are your backup destination/datafiles/archive
> log destination sharing the same physical disks? If yes than your IO
> subsystem gets more saturated. Consider optimizing your IO layout -
> dedicating seprate disks to redo logs.
>
> RMAN backup itself doesn't influence LGWR unlike online backup without
> RMAN.
>
> 2006/6/8, Sandeep Dubey <dubey.sandeep_at_gmail.com>:
> > I am using 10.2 on linux for OLTP system. I am getting log file sync
> > as top event. I can not change disk or combine transactions in one or
> > some thing other as suggested in metalink.
> >
> > Does rman backup has any effect on this event as I see this event
> > going up during backup time and performance goes down the drain.
> >
> > How can I reduce this wait event?
> >
> > Thanks
> >
> > Sandeep
> > --
> > http://www.freelists.org/webpage/oracle-l
>
> --
> Best regards,
> Alex Gorbachev
>
> http://oracloid.blogspot.com
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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