View the Exhibit and examine the Load Profile from the AWR report of a test database.
The application must process an average of 10,000 very small transactions per day. The bulk of the
processing activity is for DML operations with minimal to nil query processing.
Which two statements are correct about the values of the Physical reads events? (Choose two.)
A.
The per second value indicates the total number of data blocks read from disk to only the buffer
cache.
B.
The per transaction value includes both the db block gets and the consistent gets that occurred
during the last sample period.
C.
The per transaction value indicates that write or update transactions have been committed or
rolled back during the last sample period.
D.
The per second value indicates the total number of data blocks read from disk to the buffer
cache including reads bypassing the buffer cache, and reads into process private buffers.
C and D
Physical Reads (per transaction)
Description
This metric represents the number of disk reads per transaction during the sample period. When a user performs a SQL query, Oracle tries to retrieve the data from the database buffer cache (memory) first, then goes to disk if it is not in memory already. Reading data blocks from disk is much more expensive than reading the data blocks from memory. The goal with Oracle should always be to maximize memory utilization.
The value of this statistic will be zero if there have not been any write or update transactions committed or rolled back during the last sample period. If the bulk of the activity to the database is read only, the corresponding “per second” metric of the same name will be a better indicator of current performance.
C. D.