Re: Poor performance during log switches

What is the hardware configuration ? i.e. which physical disks with what RAID setup make which logical disks. Also, which disks are your on-line and archived redo files on ? Do other applications reside on these disks ? How fragmented are the files on those disks ? Do you have a checkpoint_process ? Do all operations on the machine go slow at log switch time or just Oracle ones ? Please set LOG_CHECKPOINTS_TO_ALERT = YES and tell us how frequently they are happening.

Eugene (Unemployed)

> We periodically experience poor performance (read this as everything stops)
> during log switches. During this period of time (4-5 minutes,) we will
> notice several new log files being created which implies a high volume of
> data changes within the database although we have not identified a
> consistent concurrent job or transaction executing. Eventually, after 4-5
> minutes, everything frees up and functions execute normally. Afterward, we
> will notice the date of creation of the new log files as being separated by
> 1 minute and sometimes even zero minutes!
>
> We have our archive log file set at 20M and we see typically 2-3 log
> switches per hour, which seems to be an optimal number.
>
> Does this 20M size seem reasonable and is there some other configuration
> setting we should be looking at to to correct this behavior?
>
> Thanks for any help in this area.
>
> Mr. Dana Smith
>
>

Eugene Gardner.
Oracle Certified dba available for hire on NT or VMS platforms. Received on Thu Jan 07 1999 - 19:12:51 CET