Computing the Hit Ratio
- Source: http://www.oreilly.com/catalog/oracle2/chapter/ch10.html
Code Block SELECT SUM(DECODE(name, 'consistent gets',value, 0)) "Consis Gets", SUM(DECODE(name, 'db block gets',value, 0)) "DB Blk Gets", SUM(DECODE(name, 'physical reads',value, 0)) "Phys Reads", (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 "Hit Ratio" FROM v$sysstat;