1select @@global.named_pipe; 2@@global.named_pipe 30 4select @@session.named_pipe; 5ERROR HY000: Variable 'named_pipe' is a GLOBAL variable 6show global variables like 'named_pipe'; 7Variable_name Value 8named_pipe OFF 9show session variables like 'named_pipe'; 10Variable_name Value 11named_pipe OFF 12select * from information_schema.global_variables where variable_name='named_pipe'; 13VARIABLE_NAME VARIABLE_VALUE 14NAMED_PIPE OFF 15select * from information_schema.session_variables where variable_name='named_pipe'; 16VARIABLE_NAME VARIABLE_VALUE 17NAMED_PIPE OFF 18set global named_pipe=1; 19ERROR HY000: Variable 'named_pipe' is a read only variable 20set session named_pipe=1; 21ERROR HY000: Variable 'named_pipe' is a read only variable 22