*/Description : Gives summary of the buffers in the SGA /*

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');