Monitoring REDO Log Buffer Tips

Oracle Database Tips by Donald BurlesonFebruary 21, 2015

Question: How do I monitor my redo log buffer in Oracle?

Answer: The Oracle redo log buffer is a small area of RAM where updates (DML) are processed for roll-forward and flashback functionality.

For related redo tuning notes, see here for details on optimal redo log_buffer sizing, and here for overall redo log tuning tips. For the whole story, see my book "Oracle Tuning: The Definitive Reference".

Starting in release 10.2 and beyond, Oracle will automatically size the log_buffer on your behalf and log_buffer cannot be changed dynamically. The automatic log_buffer sizing is based on the granule size (as determined by the hidden parameter _ksmg_granule_size):

select a.ksppinm name, b.ksppstvl value, a.ksppdesc description from x$ksppi a, x$ksppcv b where a.indx = b.indx and a.ksppinm = '_ksmg_granule_size'; NAME VALUE DESCRIPTION ------------------------------ ------------------------------ ---------------- _ksmg_granule_size 16777216 granule size in bytes

For more information on the monitoring the redo log buffer, see my notes on redo log buffer management.

For more notes on optimizing your Oracle redo log buffer size, click here.

For complete scripts to monitor the redo log buffer, download the Oracle script collection.

Oracle Training from Don Burleson

The best on site "Oracle training classes" are just a phone call away! You can get personalized Oracle training by Donald Burleson, right at your shop!

Burleson is the American Team

Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals. Feel free to ask questions on our Oracle forum.
Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications.
Errata? Oracle technology is changing and we strive to update our BC Oracle support information. If you find an error or have a suggestion for improving our content, we would appreciate your feedback. Just e-mail:
and include the URL for the page.

Burleson Consulting

The Oracle of Database Support
Oracle Performance Tuning
Remote DBA Services

Copyright © 1996 - 2020

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.

��