#
# Only global
#

select @@global.performance_schema;

--error ER_INCORRECT_GLOBAL_LOCAL_VAR
select @@session.performance_schema;

show global variables like 'performance_schema';

show session variables like 'performance_schema';

--disable_warnings
select * from performance_schema.global_variables
  where variable_name='performance_schema';

select * from performance_schema.session_variables
  where variable_name='performance_schema';
--enable_warnings

#
# Read-only
#

--error ER_INCORRECT_GLOBAL_LOCAL_VAR
set global performance_schema=1;

--error ER_INCORRECT_GLOBAL_LOCAL_VAR
set session performance_schema=1;