Query to find buffer cache details of data, rollback information

col class form A10
select decode(greatest(class,10),10,decode(class,1,'Data',2 ,'Sort',4,'Header',to_char(class)),'Rollback') "Class",
sum(decode(bitand(flag,1),1,0,1)) "Not Dirty",
sum(decode(bitand(flag,1),1,1,0)) "Dirty",
sum(dirty_queue) "On Dirty",
count(*) "Total"
from x$bh
group by decode(greatest(class,10),10,decode(class,1,'Data',2 ,'Sort',4,'Header',to_char(class)),'Rollback')
/

Note -> This is query on Oracle internal table x$