Performance Schema Status Variable Tables | VARIABLE_NAME | +---------------+ | basedir | | datadir | | log_error | | pid_file | | plugin_dir | | port | +---------------+ mysql>  SELECT VARIABLE_NAME FROM performance_schema.variables_info WHERE VARIABLE_SOURCE = ’PERSISTED’ ORDER BY VARIABLE_NAME; +--------------------------+ | VARIABLE_NAME | +--------------------------+ | event_scheduler | | max_connections | | validate_password.policy | +--------------------------+ •Display variables set from persistent storage: •Join  variables_info  with the  global_variables  table to display the current values of persisted variables, together with their range of values: mysql>  SELECT VI.VARIABLE_NAME, GV.VARIABLE_VALUE, VI.MIN_VALUE,VI.MAX_VALUE FROM performance_schema.variables_info AS VI INNER JOIN performance_schema.global_variables AS GV USING(VARIABLE_NAME) WHERE VI.VARIABLE_SOURCE = ’PERSISTED’ ORDER BY VARIABLE_NAME; +--------------------------+----------------+-----------+-----------+ | VARIABLE_NAME | VARIABLE_VALUE | MIN_VALUE | MAX_VALUE | +--------------------------+----------------+-----------+-----------+ | event_scheduler | ON | 0 | 0 | | max_connections | 200 | 1 | 100000 | | validate_password.policy | STRONG | 0 | 0 | +--------------------------+----------------+-----------+-----------+ 27.12.15 Performance Schema Status Variable Tables The MySQL server maintains many status variables that provide information about its operation (see Section 5.1.10, “Server Status Variables” ). Status variable information is available in these Performance Schema tables: • global_status : Global status variables. An application that wants only global values should use this table. • session_status : Status variables for the current session. An application that wants all status variable values for its own session should use this table. It includes the session variables for its session, as well as the values of global variables that have no session counterpart. • status_by_thread : Session status variables for each active session. An application that wants to know the session variable values for specific sessions should use this table. It includes session variables only, identified by thread ID. There are also summary tables that provide status variable information aggregated by account, host name, and user name. See Section 27.12.20.12, “Status Variable Summary Tables” . 5035