SET GLOBAL gtid_binlog_pos= '';
ERROR HY000: Variable 'gtid_binlog_pos' is a read only variable
SELECT variable_name FROM information_schema.global_variables
WHERE variable_name='gtid_binlog_pos';
variable_name
GTID_BINLOG_POS
SELECT @@gtid_binlog_pos;
SELECT @@session.gtid_binlog_pos;
ERROR HY000: Variable 'gtid_binlog_pos' is a GLOBAL variable