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