You work as a DBA and you have the responsibility of managing a large online transaction processing (OLTP) system. You used the following query during the performance tuning activity:

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 --------------- 98.43 Which understanding of this ratio is correct?

Question

You work as a DBA and you have the responsibility of managing a large online transaction processing (OLTP) system. You used the following query during the performance tuning activity:

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 --------------- 98.43 Which understanding of this ratio is correct?

Accepted Answer

D. 98.43% of times the requests have found the required data blocks in the buffer cache.

Answer

A. 98.43% of times the requests have found free buffers.

Answer

B. 98.43% of the total number of requests used the buffer cache.

Answer

C. 98.43% of times the requests were satisfied by performing physical I/Os.

You work as a DBA and you have the responsibility of managing a large online transaction processing (OLTP) system. You used the following query during the performance tuning activity: SQL> SELECT…

Question

Options

How the community answered

Community Discussion