SELECT name,value
FROM V$SYSSTAT
WHERE name IN (’db block gets’,’consistent gets’,’physical reads’); 命中率=1-physical reads/(db block gets + consistent gets)
如果命中率<0.6~0.7,则应增大DB-BLOCK-BUFFERS
FROM V$SYSSTAT
WHERE name IN (’db block gets’,’consistent gets’,’physical reads’); 命中率=1-physical reads/(db block gets + consistent gets)
如果命中率<0.6~0.7,则应增大DB-BLOCK-BUFFERS
select
sum(decode(name,'consistent gets',value,0)) consistentt,
sum(decode(name,'db block gets',value,0)) dbblockgets,
sum(decode(name,'physical reads',value,0)) physrds,
round((
(sum(decode(name,'consistent gets',value,0)) +
sum(decode(name,'db block gets',value,0)) -
sum(decode(name,'physical reads',value,0))
)/
(sum(decode(name,'consistent gets',value,0)) +
sum(decode(name,'db block gets',value,0))
)
)*100,2) Hitratio
from V$SYSSTAT;