IO Tuning

IO Related waits

SELECT
n.username,
s.sid,
s.value
FROM v$sesstat s,v$statname t, v$session n
WHERE s.statistic# = t.statistic#
AND n.sid = s.sid
AND t.name='CPU used by this session'
Page 342 Oracle DBA Code Examples
AND s.value <> 0
ORDER BY s.value desc;