You observed very low cache-hit ratio in your database as shown below:
SQL> SELECT (1-((phy.value-phyd.value) / (cur.value + con.value))) * 100
2 “Cache Hit ratio”
3 FROM v$sysstat cur, v$sysstat con, v$sysstat phy, v$sysstat phyd
4 WHERE cur.name = ‘db block gets’
5 AND con.name = ‘consistent gets’
6 AND phy.name = ‘physical reads’
7 AND phyd.name = ‘physical reads direct’;
Cache Hit Ratio
—————
68.43
After further investigation, you decided to increase the database buffer cache size. You are using the
Buffer Cache Advisor to check the appropriate size for the buffer cache. View the Exhibit and examine the graph shown by the advisory.
What can you infer from the graph?
A.
The buffer cache size can be set to 12 MB for optimal performance.
B.
The buffer cache size can be set to more than 16 MB to get more benefit.
C.
The buffer cache size can be set to more than 16 MB but there would be no benefit from it.
D.
The buffer cache size cannot be set to more than 16 MB because the SGA_MAX_SIZE value does not allow that.