Check all active processes, the latest SQL, and the SQL hit ratio

select a.status, a.sid, a.serial#, a.username, a.terminal,
a.osuser, c.Consistent_Gets, c.Block_Gets, c.Physical_Reads,
(100*(c.Consistent_Gets+c.Block_Gets-c.Physical_Reads)/
(c.Consistent_Gets+c.Block_Gets)) HitRatio, c.Physical_Reads, b.sql_text
from v$session a, v$sqlarea b, V$SESS_IO c
where a.sql_hash_value = b.hash_value
and a.SID = c.SID
and (c.Consistent_Gets+c.Block_Gets)>0
and a.Username is not null
and a.status = 'ACTIVE'
Order By a.status asc, c.Consistent_Gets desc , c.Physical_Reads desc;