There are all sorts of things you can do to speed up
the process of writing log files:
- direct io file systems
- isolate logs onto disks
- raw
- faster disks
- ultra fine grain striping
- transaction_auditing = false
etc etc etc...but the big key here is:
"Each and every record is committed"...
bad bad news there...With that policy, you'll almost
always be constricted on lgwr performance.
Cheers
Connor
- Pat Howe <PHowe_at_VERISIGN.COM> wrote: > We have a
canned package that we use to insert
> approx 100 records/second
> into one table (oltp environment).
> Each record is just under 1K (datatypes = number and
> varchar).
> There are several indexes that are build on the
> table as the records are
> inserted.
> Each and every record is committed.
> Therefore we are flushing the 'redo log buffer' to
> disk (online redo
> logfiles) 100 times per second (once per commit).
>
> Not surprisingly we have noticed IO waits which we
> believe are associated
> with our 'Redo Log buffer'. Namely ;
> log_file_sync = 180 waits/sec
> log_file_parallel_write = 180 waits/sec
>
> We tried resizing the 'redo log buffer' from 16K to
> 256K - but we did not
> notice any improvements.
> Neither Log switching or archiving seem to be
> excessive.
> 100 records per second seems to be our maximum speed
> without the application
> queuing up and Oracle showing very high waits on
> log_file_sync and
> log_file_parallel_writes.
>
> Does anyone know how we might be able to minimize
> the IO waits?
>
> Thanks in advance.
>
> ENVIRONMENT
> oracle : Oracle 8.1.7.4
> os : Sun Sparc Solaris 8
> box : 8x8 E10K
> IO : Hitachi SANS unit through fiber and Brocade
> switch
>
>
> _________________________
> Patrick J. Howe
>
>
>
> --
> Please see the official ORACLE-L FAQ:
> http://www.orafaq.com
> --
> Author: Pat Howe
> INET: PHowe_at_verisign.com
>
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Received on Wed Sep 18 2002 - 15:58:26 CDT