select @@global.shared_memory; @@global.shared_memory 0 select @@session.shared_memory; ERROR HY000: Variable 'shared_memory' is a GLOBAL variable show global variables like 'shared_memory'; Variable_name Value shared_memory OFF show session variables like 'shared_memory'; Variable_name Value shared_memory OFF select * from information_schema.global_variables where variable_name='shared_memory'; VARIABLE_NAME VARIABLE_VALUE SHARED_MEMORY OFF select * from information_schema.session_variables where variable_name='shared_memory'; VARIABLE_NAME VARIABLE_VALUE SHARED_MEMORY OFF set global shared_memory=1; ERROR HY000: Variable 'shared_memory' is a read only variable set session shared_memory=1; ERROR HY000: Variable 'shared_memory' is a read only variable