Your production database is running in the ARCHIVELOG mode and the ARCn process is functional. You have two online redo log groups. Which three background processes would be involved when a log switch happens？ （）

多项选择题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？ （）

A.increase the size of the redo log buffer
B.increase the number of redo log groups
C.increase the number of log writer processes
D.increase the number of ARCn processes
E.change the appropriate LOG_ARCHIVE_DEST_n parameter to place the archived log files in a separate location

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.