Oracle 1z0-064 問題集

質問 1：
You are administrating a database on a symmetric multiprocessing (SMP) machines. The database supports a mixed workload. You notice a large number of free buffer waits and buffer busy waits that are affecting the performance of the database. To mitigate the issue, you increase the buffer cache size, but after some time, you notice the same wait events with a high number.
Examine the parameters set for the instance:

Which two actions would you recommend to resolve the issue?
A. enabling asynchronous I/O for the file system
B. increasing the value of the DB_FILE_MULTIBLOCK_READ_COUNT parameter
C. configuring the KEEP buffer pool
D. increasing the number of DBWn processes
E. decreasing the idle time resource limit in the profile assigned to users
正解：B,E

質問 2：
A senior DBA asks you to decrease the values of the connect_time_scale and think_time_scale replay processing parameters to 50 to preprocess the workload for replay.
What three could be reasons for this change? (Choose three.)
A. to increase the number of concurrent users during replay
B. to reduce the elapsed time between two successive user calls from a session.
C. to reduce the time of replay
D. to decrease the wait for a query, caused by noncommitted transactions
E. to decrease the number of concurrent users during replay
正解：A,C,D

質問 3：
The SALES table has over one million rows. Statistics for the SALES table and its dependent objects are gathered by the Oracle AutoTask task during a predefined maintenance window.
Examine the query:

Which two actions can improve the accuracy of cardinality estimates for this query?
A. setting the OPTOMIZER_DYNAMIC_SAMPLING parameter to 4 to augment the default standard statistics
B. gathering system statistics during peak workload time to augment the standard statistics
C. setting the FORCE parameter of the GATHER_*_STATS procedure to TRUE and gathering statistics for the SALES table and its dependent objects
D. ensuring that histograms exist for the CUST_ID and PROD_ID columns
正解：B,D

質問 4：
You are administering a database that supports an OLTP workload. RESULT_CACHE_MODE is set to the default value and a result cache is configured for the instance. Multiple sessions execute syntactically similar queries without dblinks, containing functions and expressions, on tables with no DML activity. Some users complain about poor performance of these queries.
You investigate and find that the queries are frequently performing physical I/O, even though the results fetched by the queries are similar.
Which two actions do you recommend to overcome the problem affecting these queries? (Choose two.)
A. Set the RESULT_CAHCE_MODE parameter to FORCE for the instance.
B. Set the RESULT_CACHE_REMOTE_EXPIRATION parameter to a nonzero value.
C. Use bind variables for similar queries instead of literals.
D. Configure the KEEP pool and cache the queried tables used in the KEEP pool.
E. Use the result cache hint in the queries.
正解：A,E

質問 5：
In which three scenarios would you recommend the use of the SQL Performance Analyzer?
A. to analyze the impact of network and interconnect changes on database workload
B. to identify SQL statements whose performance may have regressed due to a hardware upgrade
C. to analyze the impact of using bind variables for syntactically similar SQL statements
D. to identify SQL statements that require SQL profiles
E. to analyze the impact of new indexes and materialized views on the SQL statements executed by an application
F. to identify SQL statements in an application whose performance may have regressed due to migration from Oracle Database 11g to 12c
正解：A,B,D

質問 6：
You define the warning threshold for the tablespace usage metric for the USERS tablespace to be 60% and the critical threshold to be 80%.
Which two sources should you check for the alert information when either the warning or the critical threshold is exceeded? (Choose two.)
A. DBA_ACTIVE_SESSION_HISTORY
B. DBA_ALERT_HISTORY
C. DBA_THRESHOLDS
D. the alert log
E. Oracle Enterprise Manager Cloud Control
F. DBA_OUTSTANDING_ALERTS
正解：C,D