Managing MySQL Server Logs

MySQL Server provides several logs that help us find out what activity is taking place. MySQL provides different types of log files. 
Error Log: contains information indicating when mysqld was started and stopped and also any critical errors that occur while the server is running. 
General Query Log: is a general record of what  mysqld is doing. The server writes information to this log when clients connect or disconnect, and it logs each SQL statement received from clients. 
Binary Log: contains “events” that describe database changes such as table creation operations or changes to table data. 

Relay Log: consists of the events read from the binary log of the master and written by the slave I/O thread. Slow Query Log: consists of SQL statements that took more than long_query_time seconds to execute.

MySQL server log management can be divided into 3 major steps:

1. Checking
2. Setting
3. Restart

Checking: By default, no logs are enabled. Administrator has to enable the server logging.

    mysql> show variables like '%log%';

Setting: To set the MySQL variables, use the SET keyword or make change in my.ini (mysql configuration) file.

    mysql> SET GLOBAL log = 'ON'; 

Restart: To reflect the changes, mysql services need to be restarted and enjoying logging on servers using MySQL.

    shell$ service mysqld restart