Oracle 1z0-064 問題集

質問 1：
You are administering a database that supports an OLTP workload. The CURSOR_SHARING parameter is set to EXACT for the instance. The performance of queries issued by one of the modules has degraded. The queries executed by the module are almost identical in syntax. To investigate, you analyze the latest AWR report and find a large number of latch:shared pool wait events and also a high percentage of the hard parse elapsed time.
Which two can be reasons for this? (Choose two.)
A. The CURSOR_SHARING parameter is set to EXACT, which does not allow similar queries to share a cursor.
B. Bind variables are not used for similar queries, causing hard parses.
C. Excessive time is spent on finding cached cursors in the library cache.
D. The I/O performance is slow.
E. Repeated access to a small number of blocks.
正解：B,E

質問 2：
To diagnose the performance degradation of your production database, you execute these queries:



Segment space management is manual for some of the tablespaces.
What can be the reason for the performance degradation?
A. There are too many disk sort operations.
B. PGA is undersized
C. The database writer (DBWR) process is processing buffers at a rate that is faster than the rate at which the I/O system can return the buffers.
D. Contention is caused by freelist management.
E. The buffer cache is undersized.
正解：C

質問 3：
In your database, the locally managed tablespace, USERS, has the default space usage alert set to 85% for the warning level and 97% for the critical level.
Which two statements are true? (Choose two.)
A. Alerts that are triggered are automatically recorded in DBA_ALERT_HISTORY after they are cleared.
B. Alert settings for the warning and critical levels must be disabled before taking the USERS tablespace offline.
C. Alerts are triggered when the space usage reaches the warning level, again when it reaches the critical level, and yet again when the space usage falls below the critical level.
D. Alerts are recorded in both Oracle Enterprise Manager Cloud Control and DBA_OUTSTANDING_ALERTS only when the critical threshold is exceeded.
正解：B,D

質問 4：
Examine the partial TKPROF output for an SQL statement:

Which two inferences can definitely be made from this output? (Choose two.)
A. Another transaction held a shared lock on the table, thereby causing a significant delay.
B. Array fetch operations were not performed for this query.
C. No hard parse was performed for this query.
D. An uncommitted transaction made a series of updates to the NAME_ID column just before the execution of this query.
E. The number of logical I/Os is almost equal to the number of physical I/Os.
正解：A,C

質問 5：
You are administering a database that supports an OLTP workload. An application regularly creates global temporary tables and a large number of transactions are performed on them. You notice that performance is degraded because of excessive generation of undo due to a large number of transactions on the global temporary tables.
What is the recommended action to improve performance? (Choose the best answer.)
A. Increase the size of the temporary tablespace or make it autoextensible.
B. Increase the size of the database buffer cache.
C. Increase the size of the undo tablespace and enable undo retention guarantee.
D. Enable Automatic Segment Space Management (ASSM) for the undo tablespace.
E. Enable temporary undo.
正解：C

質問 6：
Your database supports an OLTP workload where a large number of syntactically similar queries are executed. Examine the Instance Efficiency Percentages in the Automatic Workload Repository (AWR) report of the last hour:

Which two inferences can be drawn from the report?
A. The CPU is spending more time on pinning cursors in the library cache.
B. The database buffer cache is undersized and is causing contention.
C. The optimizer is waiting for resources during parsing of the queries.
D. Cursors are not getting shared in the library cache.
正解：C,D