How to monitor buffer cache and shared pool usage?

[ggnanaraj]

Use the following query to calculate the buffer cache hit ratio using the formulae given below the code:

SELECT NAME, VALUE
  FROM V$SYSSTAT
WHERE NAME IN ('session logical reads','physical reads',
               'physical reads direct','physical reads direct (lob)');

Hit Ratio = 1 - ((physical reads - physical reads direct - physical reads direct (lob)) /
(db block gets + consistent gets - physical reads direct - physical reads direct (lob))

This should be > 95%

Use the following link for the shared pool: http://download-west.oracle.com/docs...mory.htm#32137

HTH.