This is the online redo log files and the control file configurations：

Based on these configurations， which statement is true？（）

单项选择题YouaremaintainingyourOLTPdatabaseinOracle10g.Whileobservingtheperformanceofthedatabase，youfindthatthelogswitchoccursmorethanonceforevery20minutes，affectingthedatabaseperformance.Whichfactorisresponsibleforfrequentlogswitches？（）

A.the value of the UNDO_RETENTION initialization parameter
B.the value of the optimal redo log file size provided by the Redo Logfile Size Advisor
C.the online redo log files size
D.the number of redo log members in a group

单项选择题YouaremaintainingyourdatabaseinOracle10g.YouhavesetthevalueoftheSTATISTICS_LEVELinitializationparametertoTYPICALandthevalueoftheFAST_START_MTTR_TARGETparameterto900seconds.Toincreasetheperformanceofthedatabase，youwanttodeterminetheoptimalsizeoftheonlineredologfiles.Whichtoolenablesyoutodeterminetheoptimalsizeoftheonlineredologfiles？（）

A. Oracle Enterprise Manager
B. The V$LOG view
C. The V$LOGFILE view
D. The V$FLASHBACK_DATABASE_LOGS view

单项选择题Inwhichscenariowillyoucreateasortedhashcluster？（）

A. if the application uses queries joining tables only occasionally
B. if the full table scan is executed often on only one table of the clustered tables
C. if the data for all the rows of a cluster key value exceeds one or two Oracle blocks
D. when you want the data to be returned automatically in the chronological order

单项选择题You moved the index EMP_NO_INDX from one tablespace to another and then issued the following command to rebuild the index EMP_NO_INDX：   SQL> ALTER INDEX EMP_NO_INDX REBUILD ONLINE；   Which table allows the users to access the EMP_NO_INDX index while performing the rebuild operation？（）

A. Index-organized table
B. Mapping Table
C. Clustered Table
D. Journal Table

单项选择题The configuration of the online redo log files is as follows：   Based on this configuration， which statement is true？（）

A. The LGWR process concurrently writes the redo log entries to both the members of a group.
B. When a member of a group becomes corrupt， the database crashes.
C. The sizes of the redo01a.log and redo01b.log online redo log members of group Group1 can be different.
D. When redo02a.log and redo02b.log files become corrupt， then the database operations will proceed as normal.