SELECT COUNT(@@GLOBAL.mysqlx_ssl_ca); COUNT(@@GLOBAL.mysqlx_ssl_ca) 1 SET @@GLOBAL.mysqlx_ssl_ca=1; ERROR HY000: Variable 'mysqlx_ssl_ca' is a read only variable Expected error 'Read only variable' SELECT COUNT(@@GLOBAL.mysqlx_ssl_ca); COUNT(@@GLOBAL.mysqlx_ssl_ca) 1 SELECT @@GLOBAL.mysqlx_ssl_ca = VARIABLE_VALUE FROM performance_schema.global_variables WHERE VARIABLE_NAME='mysqlx_ssl_ca'; @@GLOBAL.mysqlx_ssl_ca = VARIABLE_VALUE 1 SELECT COUNT(@@GLOBAL.mysqlx_ssl_ca); COUNT(@@GLOBAL.mysqlx_ssl_ca) 1 SELECT COUNT(VARIABLE_VALUE) FROM performance_schema.global_variables WHERE VARIABLE_NAME='mysqlx_ssl_ca'; COUNT(VARIABLE_VALUE) 1 SELECT @@mysqlx_ssl_ca = @@GLOBAL.mysqlx_ssl_ca; @@mysqlx_ssl_ca = @@GLOBAL.mysqlx_ssl_ca 1 SELECT COUNT(@@mysqlx_ssl_ca); COUNT(@@mysqlx_ssl_ca) 1 SELECT COUNT(@@local.mysqlx_ssl_ca); ERROR HY000: Variable 'mysqlx_ssl_ca' is a GLOBAL variable Expected error 'Variable is a GLOBAL variable' SELECT COUNT(@@SESSION.mysqlx_ssl_ca); ERROR HY000: Variable 'mysqlx_ssl_ca' is a GLOBAL variable Expected error 'Variable is a GLOBAL variable' SELECT COUNT(@@GLOBAL.mysqlx_ssl_ca); COUNT(@@GLOBAL.mysqlx_ssl_ca) 1 SELECT mysqlx_ssl_ca = @@SESSION.mysqlx_ssl_ca; ERROR 42S22: Unknown column 'mysqlx_ssl_ca' in 'field list' Expected error 'Readonly variable'