Re: Redo Log Size

From: John P. Higgins <jh33378nospam_at_deere.com>
Date: 1997/12/09
Message-ID: <348DA9B4.2C84@deere.com>#1/1

Kurt Tucker wrote:
>
> Is there any guidlines when sizing redo logs? I will be running in
> archivelog mode and want to get fewer log files while not degrading
> performance.
>
> thanx
> -rat

It all depends on the activity level. On a busy database, I increased the redo log files from 20MB to 200MB. Then I queried V$LOG_HISTORY and used Excel to analyze the time between logs. I found that 10% the log switches were over 400 minutes apart. On the other end of the scale, 10% of the log switches were only 4 minutes apart. The median time was about 23 minutes.

I think a median time in the 30 minute ballpark is about right, so I am satisfied with this setting. If the activity increases, I'll again increase the size.

I also implemented LOG_CHECKPOINT_TIMEOUT to be sure I got at least one checkpoint every 30 minutes.

John Received on Tue Dec 09 1997 - 00:00:00 CST