Buffer Hit Ratio

From: Verma <ranju-ravi_at_worldnet.att.net>
Date: 9 Jun 1999 03:33:24 GMT
Message-ID: <01beb1fe$ae062380$14ac4e0c@Verma.medco.com>

From one of my references, I found this sql to calculate the buffer hit ratio :

select decode(name,'physical reads',value)/ (decode(name,'consistent gets',value) + decode(name,'db block gets',value) ) as hit_ratio from v$sysstat
where name in ('physical reads','consistent gets','db block gets') ;

But when I try to run this sql, no value appears for the hit ratio.

If I query v$sysstat the values do exist individually for the three parameters.

Any clue what is going wrong ?

Thanks in advance Received on Tue Jun 08 1999 - 22:33:24 CDT