Which statement is true about the loss of system­critical data files in ARCHIVELOG mode？（）

多项选择题Inyourdatabase，theLogWriter（LGWR）processisunabletowritetoamemberofacurrentredologgroupduetoread writefailure.Whichtwoeffectswouldyouseeinyourdatabase？（）

A.The database instance aborts.
B.The database operation temporarily halts till the member becomes available.
C.Writing proceeds as normal. LGWR writes to the available members of a group and ignores the unavailable members.
D.The member would be marked as STALE and an error message would be written to the alert log file and LGWR trace file.
E.The status of the group changes to INACTIVE and an error message would be written to the alert log file and LGWR trace file.

多项选择题Your database is configured in NOARCHIVELOG mode. All the control files have been lost due to a hard disk failure but the data files are not lost. You have the closed whole database backup available to you.  Which two statements are true in this scenario？（）

A.The instance aborts.
B.The database cannot be recovered.
C.The database can be recovered by restoring the control files from the backup.
D.The database remains opened and you have to shut it down with the ABORT option.
E.The database can be restored till the point of the last closed whole database backup.

单项选择题Accordingtoyourbackupstrategy，youperformedanincrementallevel0backupofyourdatabase.Whichstatementregardingthisbackupistrue？（）

A.The backup is similar to image copy.
B.The backup contains all used data blocks.
C.The backup contains only unused data blocks.
D.The backup contains all data blocks changed since the last incremental level 1 backup.

单项选择题You want to monitor and control the resource usage by sessions. You want to be warned automatically when more than 100 sessions are opened with your database.  What action would you take to achieve this？（）

A.Use the Database Resource Manager.
B.Set the limits in the profiles used by users.
C.Modify the SESSIONS initialization parameter.
D.Set the warning threshold for the Current Logons Count metric.

单项选择题Theapplicationworkloadonyourdatabaseissamebetween10a.m.and11a.m.onweekdays.Suddenlyyouobservepoorperformancebetween10a.m.and11a.m.inthemiddleoftheweek.Howwouldyouidentifythechangesinconfigurationsettings，workloadprofile，andstatisticstodiagnosethepossiblecausesoftheperformancedegradation？（）

A.by using the SQL access advisor
B.by using the Automatic Workload Repository report
C.by running the Automatic Database Diagnostic Monitor （ADDM）
D.by using the Automatic Workload Repository Compare Period report
E.by analyzing the output of the V$ACTIVE_SESSION_HISTORY view