单选题Your boss at Certkiller .com wants you to clarify Oracle 10g. Which statement regarding the usage of redo log files during instance recovery is true？（）A Transactions are rolled back using redo log files.B Transactions are rolled forward using redo log 

第1题：

Which statement is true regarding the Archiver （ARCn） process，archived log files，and recovery？ （）

• A、A database backup, combined with archived redo log files, guarantees that all committed data can be recovered to the point of failure. 
• B、During recovery the ARCn background process copies its redo entries identified for recovery by the control file to the data files. 
• C、After each write to an archived log, the mandatory background process ARCn writes its log sequence number and the first and last SCN number within the log sequence to the control file. 
• D、At database recover time, and archived redo log is uniquely identified for recovery use by its redo thread number and destination ID number retrieved from the control file.

第2题：

You are in the middle of a transaction updating a very important table. The machine on which a database wasrunning reboots because of power outage. This caused a database instance failure. Which statement is true inthis 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

第3题：

第4题：

You are maintaining your database in Oracle10g. You are not using the recovery catalog to maintain the backup information of your database. Which file can be used as a repository to store information regarding the RMAN backup？（）

• A、 online redo log files
• B、 alert log files
• C、 control file
• D、 datafiles associated with the SYSTEM tablespace

第5题：

You work as a database administrator for Certkiller .com. Users in the Certkiller PROD database complain about the slow response when accessing the database. In the Active Session Waiting： Configuration page you find that the majority of the wait time is for the redo log buffer.Further investigation using the Run Queue graph and operating system tools reveals that the redo log files are on the same disks， and that the disk I/O for the redo log files is the reason for the performance degradation.  Which two actions would you take to gain performance？（）

• A、Increase the size of redo log files
• B、Increase the size of redo log buffer
• C、Increase the number of redo log files
• D、Place the redo log files on a separate disk
• E、Decrease the number of redo log groups to two
• F、Increate the number Log Writer （LGWR） process

第6题：

Your boss at Certkiller .com wants you to clarify Oracle 10g. Which statement regarding the usage of redo log files during instance recovery is true？（）

• A、Transactions are rolled back using redo log files.
• B、Transactions are rolled forward using redo log files.
• C、Transactions are rolled back using redo log files and archived log files.
• D、Transactions are rolled forward using redo log files and rolled back using redo log files.

第7题：

You are using Oracle Database 10g. You performed an  incomplete recovery of your database and opened the database with the RESETLOGS option.  What is the effect of opening the database with the RESETLOGS option？（）

• A、This operation resets the SCN for the database.
• B、This operation creates a new incarnation of the database.
• C、This operation moves all the redo log files to a different location.
• D、This operation deletes the old redo log files and creates new redo log files.
• E、This operation updates all current datafiles and online redo logs and all subsequent archived redo logs with a new RESETLOGS SCN and time stamp.

第8题：

The instance abnormally terminates because of a power outage.  Which statement is true about redo log filesduring instance recovery（）

• A、Inactive and current redo log files are required to accomplish recovery.
• B、Online and archived redo log files are required to accomplish instance recovery.
• C、All redo log entries after the last checkpoint are applied from redo log files to data files.
• D、All redo log entries recorded in the current redo log file until the checkpoint position are applied to data files

第9题：

You performed an incomplete recovery and opened the database with the RESETLOGS option. The LOG_ARCHIVE_FORMAT parameter is set to ’ora_%t_%s_%r.log’.  Which statement regarding the archived redo log files， created in an earlier incarnation of the database，is true？（）

• A、 The archived redo log files will be overwritten.
• B、 The archived redo log files are deleted automatically.
• C、 The archived redo log files should be moved to some other location.
• D、 The archived redo log files are still maintained because the file names are unique.

第10题：

In the parameter file of your production database， the FAST_START_MTTR_TARGET parameter is set to 300 to optimize instance recovery. While observing the performance of the database during instance recovery， you find that the redo log files are not sized properly to support this activity. Which two sources could you use to determine the optimal size of the redo log files？（）

• A、the V$LOG view
• B、the V$DBFILE view
• C、the V$LOGFILE view
• D、the V$INSTANCE_RECOVERY view
• E、Oracle Enterprise Manager Database Control