Verificar HIT_RATIO - Taxa de acerto de Buffer

select
100 -
100 *
(round ((sum (decode (name, 'physical reads',
value, 0))
-
sum (decode (name, 'physical reads direct',
value, 0)) -
sum (decode (name,
'physical reads direct (lob)',
value, 0))) /
(sum (decode (name, 'session logical reads',
value, 1))
),3)) hit_ratio
from
sys.v_$sysstat
where
name in
('session logical reads',
'physical reads direct (lob)',
'physical reads',
'physical reads direct');