MySQL Manual
4 Database Administration
4.9.6 Log File Maintenance
The MySQL Server can create a number of different log files, which make it easy to see what is going on. See section 4.9 The MySQL Log Files. One must however regularly clean up these files, to ensure that the logs don't take up too much disk space.
When using MySQL with log files, you will, from time to time, want to remove/backup old log files and tell MySQL to start logging on new files. See section 4.4.1 Database Backups.
On a Linux (Red Hat) installation, you can use the
mysql-log-rotate script for this. If you installed MySQL
from an RPM distribution, the script should have been installed
automatically. Note that you should be careful with this if you are using
the log for replication!
On other systems you must install a short script yourself that you
start from cron to handle log files.
You can force MySQL to start using new log files by using
mysqladmin flush-logs or by using the SQL command FLUSH LOGS.
If you are using MySQL Version 3.21 you must use mysqladmin refresh.
The above command does the following:
-
If standard logging (
--log) or slow query logging (--log-slow-queries) is used, closes and reopens the log file (`mysql.log' and ``hostname`-slow.log' as default). -
If update logging (
--log-update) is used, closes the update log and opens a new log file with a higher sequence number.
If you are using only an update log, you only have to flush the logs and then move away the old update log files to a backup. If you are using the normal logging, you can do something like:
shell> cd mysql-data-directory shell> mv mysql.log mysql.old shell> mysqladmin flush-logs
and then take a backup and remove `mysql.old'.
