DESC sys.memory_global_total;
Field	Type	Null	Key	Default	Extra
total_allocated	text	YES		NULL	
SELECT * FROM sys.memory_global_total;
DESC sys.x$memory_global_total;
Field	Type	Null	Key	Default	Extra
total_allocated	decimal(41,0)	YES		NULL	
SELECT * FROM sys.x$memory_global_total;