RE: log file sync wait

Which was also used primarily for cheating on benchmarks, only in a little bit more subtle manner.

Mladen Gogala
Oracle DBA
Phone:(203) 459-6855
Email:mgogala_at_oxhp.com

-----Original Message-----
Sent: Monday, May 05, 2003 5:32 PM
To: Multiple recipients of list ORACLE-L

If i remember well, there is also a _wait_for_synch or similar ...

"Gogala, Mladen" wrote:
>
> We're not talking about "_disable_logging", an ancient parameter
> for cheating on benchmarks, are we? I've tried that and if anything
> happens, the database doesn't come up. Other then the possibility
> that you might lose all your data, everything works fine and the
> database is flying like a greased lightning.
>
> Mladen Gogala
> Oracle DBA
> Phone:(203) 459-6855
> Email:mgogala_at_oxhp.com
>
> -----Original Message-----
> Sent: Monday, May 05, 2003 5:07 AM
> To: Multiple recipients of list ORACLE-L
>
> Ganesh:
>
> Not very true. Slower log files with bigger log buffers are the main
> cause for log file sync waits. THis typically happens during a
> transaction end, either commit or rollback will make others wait for
> the log file sync.
>
> To reduce this, you can keep the redo logs in the fastest disk, use
> no-logging wherever you can, reduce the commits,tune the
> sessions/processes parameter. And also there is an underscore parameter
> which will completely eliminate the log_file_sync waits. But that is
> against the Oracle's implementation of the ACID property in the
> transactional database system. You can use them during batch loads,
> benchmarks, _non_ production systems and test systems. But then the
> committed transactions are not necessarily committed transactions.
>
> --- ganesh_raja_at_non.agilent.com wrote:
> > Ur Log file sync wait is mainly because your Log Buffer is small and
> > every time Logwr Writes the redo into the Redo Logs your apps are
> > waiting for the sync to complete.
> >
> > Run Your Lgwr in Parallel using IO Slaves or use Async_IO parameter
> > ro control it from OS.
> > Increase the size of your LOGBuffer so that the ur App does not wait
> > for the syncs..
> >
> > HTH
> >
> > Best Regards,
> > Ganesh R
>
> =====
> Have a nice day !!
> ------------------------------------------------------------
> Best Regards,
> K Gopalakrishnan,
> Bangalore, INDIA.
> --

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