Archive log file size

[lgaorcl]

There are some batch jobs running everyday in one of my database. I checked the frequency of log switchs for the archive log files, some of them get to 4-6 times every minutes. The size of redo is 15M, and there are 4 groups. Is this too frequent? What frequency would be appropriate? What impact would it have on database if redo log file size is not big enough?

Thanks!

[sambavan]

Oh yeah!!. That is too frequent. Check your check point interval and normally, oracle suggests a logswitch for every 30min or so. This high frequency would keep the DBWR and LGWR processes in the v.hot spot. It also could cause the log contention.

Sam

[lgaorcl]

Log_checkpoint_interval = 10000
log_checkpoint_temeout = 1800

How do these two parameters affect the frequency of log switch?

Thanks!

[sambavan]

Originally posted by lgaorcl
Log_checkpoint_interval = 10000

http://oradoc.photo.net/ora817/DOC/s...h189.htm#55753

log_checkpoint_temeout = 1800

http://oradoc.photo.net/ora817/DOC/s...ch190.htm#5517

[BV1963]

I would suggest to increase size of redo log to at least 50Mb.It will buy some time before they filled ip and have to be archived.

[sambavan]

Remember the larger the redolog the longer would be the recovery time too...

Sam

[lgaorcl]

Thanks for the help! I am planning to increase the size of redo. How necessary is it to shutdown database to recreate redo files?

What's the impact if I don't shutdown database?

[marist89]

The best way to add logfiles while the instance is up is to:
1. add logfile groups of the right size and number
2. carefully watch to see when the logfiles are being used. When the smaller logfiles are INACTIVE you can drop them. Use http://home.adelphia.net/~marist89/s...ch_logfile.htm to watch the logfile...


[Edited by marist89 on 11-30-2001 at 04:20 PM]

[sambavan]

Hey Jeff,

Looks like Uncle Bill had lent his hands to a Unix buff.

Jeff's web site . It looks good!

Sam

[marist89]

Yeah, I figured it was time to put my scripts online. That way, whenI'm answering questions I can just point people to the site...

Maybe UB can't write a server OS, but he has some kick ass desktop tools...