The instance abnormally terminates because of a power outage. Which statement is true about redolog files during instance recovery（）

多项选择题Younoticethattheperformanceofthedatabasehasdegradedbecauseoffrequentcheckpoints.Whichtwoactionsresolvetheissue（）

A.Disable automatic checkpoint tuning.
B.Check the size of the redo log file size and increase the size if it is small.
C.Set the FAST_START_MTTR_TARGET parameter as per the advice given by the MTTR Advisor. 
D.Decrease the number of redo log members if there are more than one redo log members available in each redo log group.

多项选择题Whichtwostatementsaretrueaboutcheckpointing（）

A.The checkpoint frequency decreases with the smaller redo log file size.
B.It ensures that all committed data is written to the data files during normal shutdown.
C.The frequent full checkpoint in a database can cause the overall degradation of the database performance.
D.It prompts the Checkpoint （CKPT） process to write data to the data files and redo information to the online redo log files.

多项选择题Which two statements are true about setting the FAST_START_MTTR_TARGET initializationparameter to a nonzero value（）

A.The MTTR advisor will be disabled.
B.Automatic checkpoint tuning will be enabled.
C.The value for the LOG_CHECKPOINT_INTERVAL initialization parameter will be override the value forFAST_START_MTTR_TARGET.
D.The time taken to recover the instance after the crash is always exactly the same as the value given forthe FAST_START_MTTR_TARGET initialization parameter.

单项选择题ou are in the middle of a transaction updating a very important table. The machine on which adatabase was running reboots because of power outage. This caused a database instance failure.  Which statement is true in this situation（）

A.The online redo log files and archived redo log files are required to accomplish the recovery.
B.The uncommitted transaction will be committed at the next startup of the database instance.
C.The uncommitted transaction is rolled back automatically at the next opening of the database.
D.The DBA has to perform the recovery on the database to recover the uncommitted transaction.

单项选择题Given below is a list of scenarios：  1）A user terminates his session abnormally.  2）The connection between the server and the client application terminates because of a network failure.  3）A schema is accidentally dropped.  4）The tablespace is accidentally dropped from the database.  5）The hard disk gets corrupted and the data files in the disk are lost.  6）The database instance abnormally shuts down because of power failure.  Which scenarios require DBA intervention to perform recovery（）

A.4 and 5
B.1，3，and 6
C.4，5，and 6
D.3，4，and 5
E.1，2，and 6