1select @@global.performance_schema; 2@@global.performance_schema 31 4select @@session.performance_schema; 5ERROR HY000: Variable 'performance_schema' is a GLOBAL variable 6show global variables like 'performance_schema'; 7Variable_name Value 8performance_schema ON 9show session variables like 'performance_schema'; 10Variable_name Value 11performance_schema ON 12select * from information_schema.global_variables 13where variable_name='performance_schema'; 14VARIABLE_NAME VARIABLE_VALUE 15PERFORMANCE_SCHEMA ON 16select * from information_schema.session_variables 17where variable_name='performance_schema'; 18VARIABLE_NAME VARIABLE_VALUE 19PERFORMANCE_SCHEMA ON 20set global performance_schema=1; 21ERROR HY000: Variable 'performance_schema' is a read only variable 22set session performance_schema=1; 23ERROR HY000: Variable 'performance_schema' is a read only variable 24