You are analyzing the components of the redo log mechanisms 

第1题：

You are maintaining your OLTP database in Oracle10g. While observing the performance of the database， you find that the log switch occurs more than once for every 20 minutes， affecting the database performance. Which factor is responsible for frequent log switches？（）  

• 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

第2题：

You have configured the flash recovery area to store online redo log files， control files， archived redo logs and RMAN backups. Which of the following files can you successfully delete from the flash recovery area if you want to reclaim the space within it？（）

• A、 multiplexed control files
• B、 RMAN obsolete backups
• C、 multiplexed online redo log files
• D、 archived redo logs that have not been copied to tape

第3题：

第4题：

You are working on a database， where you have three redo log groups. When the database is down for a backup， an operating system （OS） user deletes all the redo log files in a group. What will happen when you open your database？（）

• A、 The instance starts， the database is mounted， but efforts to open the database fail， and an error about the missing redo log group is displayed.
• B、 Before the instance starts， you receive an error about the missing redo log files of a group.
• C、 The instance starts and the database opens with an error message written to the alert log file.
• D、 The instance starts and the database opens because two redo log groups still exist.
• E、 The instance starts and the database opens， but every attempt to write to redo log files fails with an error.

第5题：

You have the following online redo log configuration：    Group       Member   1     ’/disk1/oradata/redo01a.log’   2     ’/disk2/oradata/redo02a.log’   3     ’/disk3/oradata/redo03a.log’   You decide to multiplex the online redo log groups for recovery of redo log files in case of any disaster. Which two statements will you NOT issue to multiplex the online redo log files？（）

• A、 ALTER DATABASE ADD LOGFILE MEMBER ’/disk1/oradata/redo01b.log’ TO GROUP 1；
• B、 ALTER DATABASE ADD LOGFILE MEMBER ’/disk2/oradata/redo01b.log’ TO GROUP 1；
• C、 ALTER DATABASE ADD LOGFILE MEMBER ’/disk1/oradata/redo02b.log’ TO GROUP 2；
• D、 ALTER DATABASE ADD LOGFILE MEMBER ’/disk2/oradata/redo02b.log’ TO GROUP 2；
• E、 ALTER DATABASE ADD LOGFILE MEMBER ’/disk1/oradata/redo3b.log’ TO GROUP 3；
• F、 ALTER DATABASE ADD LOGFILE MEMBER ’/disk2/oradata/redo3b.log’ TO GROUP3；

第6题：

Because of hardware failure， you decided to drop a redo log member from the database. Which condition should be met to drop a redo log file？（）

• A、 The redo log file should belong to an active group.
• B、 The redo log file should belong to an inactive group.
• C、 The redo log file should belong to the current group.
• D、 The redo log file can be dropped only if all the transactions are stopped.
• E、 Before a redo log file is dropped， it should be deleted from the operating system （OS）.

第7题：

The database is running in the ARCHIVELOG mode. It has three redo log groups with one member each. Oneof the redo log groups has become corrupted. You have issued the following command during the recovery of a damaged redo log file:ALTER DATABASE CLEAR UNARCHIVED LOGFILE GROUP 3; Which action should you perform immediately after using this command?（）

• A、You should perform a log switch
• B、You should make a backup of the database
• C、You should switch the database to the NONARCHIVELOG mode
• D、You should shut down the database instance and perform a complete database recovery

第8题：

Redo log files are multiplexed in your database. The disk in which you have one of the redo log members is highly fragmented. In the process of defragmentation you lose the redo log member， which is not a member of the current group. How would you recover from the loss of the redo log member？（）

• A、SMON would automatically restore the lost file.
• B、You would need to restore the whole database from the last backup.
• C、You would need to restore the file from the last full database backup.
• D、You would need to use flashback technology to restore the lost redo log member.
• E、You would need to use Recovery Manager （RMAN） to restore the lost redo log member.
• F、You would need to restore the missing log file by copying one of the remaining files from the same group.

第9题：

While performing the backup of the flash recovery area, you notice that one of the archived redo log files is missing. You have multiple destinations for archived redo log files. What implications does it have on the backup of the flash recovery area?（）

• A、The backup fails because one of the archived redo log files is missing. 
• B、The backup succeeds but it would be without the missing archived log. 
• C、During backup, you are prompted for the alternative destination for the missing archived redo log file. 
• D、The backup succeeds because it fails over to one of the alternative archived redo log destinations. 

第10题：

Which statement about recovering from the loss of a redo log group is true?（）

• A、If the lost redo log group is ACTIVE, you should first attempt to clear the log file.
• B、If the lost redo log group is CURRENT, you must clear the log file.
• C、If the lost redo log group is ACTIVE, you must restore, perform cancel-based incomplete recovery, and open the database using the RESETLOGS option.
• D、If the lost redo log group is CURRENT, you must restore, perform cancel-based incomplete recovery, and open the database using the RESETLOGS option.