Oracle的数据缓存命中率

数据缓存命中率
select sum(decode(name,'physical reads',value,0))  "Physical Reads",
       sum(decode(name,'db block gets',value,0))   "Db Block Reads",
       sum(decode(name,'consistent gets',value,0)) "Consistent Reads",
       (1-(sum(decode(name,'physical reads',value,0))/
          (sum(decode(name,'db block gets',value,0))+
          sum(decode(name,'consistent gets',value,0)))))*100 "Hitratio"
from v$sysstat;

数据字典命中率
select 1-(sum(getmisses)/sum(gets)) "data dictonary hit ratio" from v$rowcache;