select @@global.performance_schema_max_table_handles; @@global.performance_schema_max_table_handles 123 select @@session.performance_schema_max_table_handles; ERROR HY000: Variable 'performance_schema_max_table_handles' is a GLOBAL variable show global variables like 'performance_schema_max_table_handles'; Variable_name Value performance_schema_max_table_handles 123 show session variables like 'performance_schema_max_table_handles'; Variable_name Value performance_schema_max_table_handles 123 select * from information_schema.global_variables where variable_name='performance_schema_max_table_handles'; VARIABLE_NAME VARIABLE_VALUE PERFORMANCE_SCHEMA_MAX_TABLE_HANDLES 123 select * from information_schema.session_variables where variable_name='performance_schema_max_table_handles'; VARIABLE_NAME VARIABLE_VALUE PERFORMANCE_SCHEMA_MAX_TABLE_HANDLES 123 set global performance_schema_max_table_handles=1; ERROR HY000: Variable 'performance_schema_max_table_handles' is a read only variable set session performance_schema_max_table_handles=1; ERROR HY000: Variable 'performance_schema_max_table_handles' is a read only variable