> select 1-(phy.value - lob.value -dir.value)/ ses.value "cache hit ratio"
>   from v$sysstat ses, v$sysstat lob, v$sysstat dir, v$sysstat phy
>   where ses.name = 'session logical reads'
>   and dir.name = 'physical reads direct'
>   and lob.name = 'physical reads direct (lob)'
>   and phy.name = 'physical reads'

SQL水着というのを考えた

参考：2007/05/27(日)23時09分19秒