Re: Log Switching

You are correct. It is very likely that your batch process is being slowed down by
dbwr working harder than it needs to, and an increase in the sizes of log files may help.

(The worst case I ever saw was a batch job dropping from 7 hours to 90 minutes after changing from 2x 512K log files to 5 x 10 Mb log files, but that was a bit extreme).

If you are worried that putting the log files to a much larger size may increase the risk of data loss during the day, you can also set a 'log_checkpoint_timeout (in seconds) in the init.ora to force a checkpoint at regular intervals.

A good size for logfiles is very much system and business dependent, but a frequent guideline is to set the size so that a switch occurs at about 15 to 30 minutes intervals.

--

Jonathan Lewis
Yet another Oracle-related web site: www.jlcomp.demon.co.uk

M. Bhatti wrote in message <372DC548.4919C5C2_at_mci.com>...
>During batch processing, I notice a lot of log switches in the alert.log
>file. I assume that during a log switch, a checkpoint ocurrs and the
>dbwr writes changed blocks to the datafiles. For better performance,
>would it be a better idea to increase the size of the log files (Oracle
>8.0.5 on Soalris 2.5.1) so that fewer log switches ocurred.
Received on Mon May 03 1999 - 11:03:30 CDT