SELECTROUND(100- 100 * SUM(DECODE(NAME,'physical reads',VALUE,0)) /
(SUM(DECODE(NAME,'db block gets from cache',VALUE,0)) +
SUM(DECODE(NAME,'consistent gets from cache',VALUE,0))), 2)
"DB CACHE HIT RATE(%)"
FROM
V$SYSSTAT
WHERE
NAME IN
(
'physical reads', 'db block gets from cache',
'consistent gets from cache'
);
-- またはSELECTROUND(100- 100 * SUM(DECODE(NAME,'physical reads',VALUE,0)) /
(SUM(DECODE(NAME,'db block gets',VALUE,0)) +
SUM(DECODE(NAME,'consistent gets',VALUE,0))), 2)
"DB BUFFER HIT RATE(%)"
FROM
V$SYSSTAT
WHERE
NAME IN
('physical reads', 'db block gets', 'consistent gets');
関連 初期化パラメータ DB_CACHE_SIZE / (DB_BUFFER_SIZE)
隠し初期化パラメータ
隠しパラメータ(要 SYS権限) / Kernel Service, Parameter
SELECT PI.KSPPINM NAME , SV.KSPPSTVL VALUE, PI.KSPPDESC DES
FROM X$KSPPI PI, X$KSPPCV SV
WHERE PI.INDX = SV.INDX AND PI.KSPPINM LIKE '\_%' ESCAPE '\'