From: Michael Widenius
Date: April 17 1999 8:20am
Subject: Log file
List-Archive: http://lists.mysql.com/mysql/1975
Message-Id: <14104.17436.155039.111800@monty.pp.sci.fi>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

>>>>> "Chai-Hup" == Chai-Hup Chen <hup@stripped> writes:

Chai-Hup> Hi,
Chai-Hup>   The log file under /db_dir/mysql/var/my_host.log may grow to be very 
Chai-Hup> huge (>1G each week in my case), which is too big to be read. 

Chai-Hup> Since I have a live system, I can't use a script to remove the log file, 
Chai-Hup> shutdown and restart mysqld. Any way that I can keep the log file in a 
Chai-Hup> readable size?


Hi!

I just added the following entry to the MySQL manual. Hope it helps:

------
Log file maintenance
====================

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.  *Note Update log::

One a Linux (`Redhat') 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 automaticly.

On other systems you must yourself install a short script 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'.

The above command does the following:

   * If standard logging (`--log') is used, closes and reopens the log
     file.  (`mysql.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 only are using 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:

     cd mysql-data-directory
     mv mysql.log mysql.old
     mysqladmin flush-tables

and then take a backup and remove `mysql.old'.

------------------