The MySQL server, mysqld, has many command options and system variables that can be set at startup to configure its operation. To determine the default command option and system variable values used by the server, execute this command:
$> mysqld --verbose --help
The command produces a list of all mysqld options and configurable system variables. Its output includes the default option and variable values and looks something like this:
To see the current system variable values actually used by the server as it runs, connect to it and execute this statement:
mysql> SHOW VARIABLES;
To see some statistical and status indicators for a running server, execute this statement:
mysql> SHOW STATUS;
System variable and status information also is available using the mysqladmin command:
$> mysqladmin variables
$> mysqladmin extended-status
For a full description of all command options, system variables, and status variables, see these sections:
More detailed monitoring information is available from the
Performance Schema; see Chapter 29, MySQL Performance Schema. In
addition, the MySQL
sys schema is a set of
objects that provides convenient access to data collected by the
Performance Schema; see Chapter 30, MySQL sys Schema.
If you specify an option on the command line for mysqld or mysqld_safe, it remains in effect only for that invocation of the server. To use the option every time the server runs, put it in an option file. See Section 184.108.40.206, “Using Option Files”.
Windows users may execute Section 2.3.2, “Configuration: Using MySQL Configurator” to help configure a MySQL server installation. This includes tasks such as configuring MySQL users, log files, the Windows service name, and sample databases.