In your production database， you have observed that the database server performance degrades whenever there is a switch between the log groups. On further investigation， you find that the database is running in ARCHIVELOG mode and the archived log files are being written to the same disk that is used to store the redo log members. 
Which two actions would you take to improve the performance of the database server？ （）

多项选择题You want to use the SQL Tuning Advisor to generate recommendations for badly written SQL statements in your development environment.   Which three sources can you select for the advisor to analyze？ （）

A.Top SQL
B.snapshots
C.SQL Tuning sets
D.index access path
E.optimizer statistics
F.materialized view logs

单项选择题You find that the execution time of reports in your datawarehouse application is significantly high. You suspect the lack of indexes to be the reason for the degradation in performance.  Which advisory component would you refer to， in order to determine the appropriate indexes？（）

A.Memory Advisor
B.Segment Advisor
C.SQL Access Advisor
D.Automatic Workload Repository （AWR）
E.Automatic Database Diagnostic Monitor （ADDM）

单项选择题You observe that database performance has degraded over a period of time. While investigating the reason， you find that the size of the database buffer cache is not large enough to cache all the needed data blocks.  Which advisory component would you refer to， in order to determine the required size of the database buffer cache？（）

A.Memory Advisor
B.Segment Advisor
C.SQL Tuning Advisor
D.SQL Access Advisor
E.Automatic Database Diagnostic Monitor （ADDM）

多项选择题You are performing a block media recovery on the tools01.dbf data file in the SALES database by using RMAN.   Which two statements are correct in this scenario？（）

A.You must ensure that the SALES database is mounted or open.
B.You must restore a backup control file to perform a block media recovery.
C.You must take the tools01.dbf data file offline before you start a block media recovery.
D.You must put the database in NOARCHIVELOG mode to perform a block media recovery.
E.You can perform only a complete media recovery of individual blocks； point-in-time recovery of  individual data blocks is not supported.

单项选择题Your database is open and running in ARCHIVELOG mode. You take RMAN full backups every Sunday night. On Monday morning， while querying the user1.employees table， you receive the following error message：  01578： ORACLE data block corrupted （file # 5， block # 51） ORA-01110： data file 5：  ’ u01 app oracle oradata orcl example01.dbf’  You need to rectify the corruption while ensuring the following： The data file should remain online.  The mean time to recover （MTTR） should be minimal.  You are not using a backup control file， and all the archived logs are accessible.   Which option would you choose？（）

A.flash back the corrupted blocks
B.use the DBMS_REPAIR package
C.use the RMAN TSPITR command
D.use the RMAN BLOCKRECOVER command
E.use the RESTORE DATABASE and RECOVER DATABASE commands
F.investigate the time at which the corruption occurred and perform a point-in-time recovery