Chapter 4 - Database Recovery
Review Questions
1. What is another name for RMAN-based database recovery?
A. User-managed recovery
B. Server-managed recovery
C. Traditional recovery
D. Database recovery
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Ans: B. Server-managed recovery is another name for RMAN recovery because the server
session performs the recovery process as it interacts with the target database.
2. What command is responsible for automating the backup of control files?
A. ALTER DATABASE CONTROLFILE AUTOBACKUP ON
B. ALTER SYSTEM CONTROLFILE AUTOBACKUP ON
C. CONFIGURE CONTROLFILE AUTOBACKUP ON
D. ENABLE CONTROLFILE AUTOBACKUP
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Ans: C.
The control file autobackup is enabled by setting parameters within RMAN by
using CONFIGURE CONTROLFILE AUTOBACKUP ON.
3. What is the process to recover a control file?
A. Start up database, restore control file, start up mount the database, recover the database, and open the database.
B. Start up mount, restore control file, start up the database, recover the database, and open the database.
C. Start up nomount, restore control file, start up mount the database, recover the database, and open the database.
D. Start up force, restore control file, start up the database, recover the database, and open the database.
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Ans: C.
The database needs to be started in NOMOUNT mode because there is not a control file available to MOUNT the database. Next, the control file can be restored. Once a restored control file is available, the database can be started in MOUNT mode so that standard database recovery can continue. When recovery is complete, the database can OPEN for normal use.
4. When recovering a control file without the recovery catalog, what special step must be performed to identify the target database? (Choose all that apply.)
A. You must CONNECT TARGET / to the target database within RMAN.
B. You must STARTUP MOUNT the database because the control file is missing.
C. You must SET DBID to the target database so that the target database can be identified without the control file available.
D. You must CONNECT TARGET database name to the target database within RMAN.
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ANs: A, C.
The target database is not identifiable by database name without the control
file. So you must first use the CONNECT TARGET / command to connect. The target
database needs to be identified by the database identifier (DBID) number with the
command SET DBID database identifier. This database identifier number denotes the
target database. When you are recovering the control file, the target database
identification is not available because it is stored in the control file.
5. After you restore the control file, what must you do before you execute the RECOVER command to apply archive logs?
A. The database must be restored with the RESTORE command.
B. The database must be reconnected with the CONNECT TARGET database name command.
C. The database must be started in MOUNT mode.
D. The database must open for use with ALTER DATABASE OPEN command.
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Ans: C. The database must be mounted before the RECOVER command can be executed.
You first must restore control so you can MOUNT the database.
6. Which of the following methods should you use for creating a control file?
(Choose all that apply.)
A. Dump the control file information to a trace file.
B. Use the ALTER DATABASE BACKUP CONTROLFILE TO TRACE command.
C. Use the CREATE CONTROLFILE command.
D. None of the above.
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Ans: A, B.
The ALTER DATABASE BACKUP CONTROL FILE TO TRACE command creates a
user trace file, which stores an ASCII representation of the binary control file.
7. What are the two cases defined in the backup control file? (Choose two.)
A. ALTER DATABASE OPEN
B. ALTER DATABASE OPEN RESETLOGS
C. ALTER DATABASE OPEN NORESETLOGS
D. ALTER DATABASE OPEN NORESET
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Ans: B, C.
The two cases in the backup control file are opening the database with RESETLOGS or NORESETLOGS.
8. Which files need to be available and in the matching location of the ASCII
control file in order to rebuild the control file? (Choose all that apply.)
A. Server file, PFILE or SPFILE
B. Datafiles
C. Control files
D. Redo logs
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Ans: A, B.
The server file, SPFILE or PFILE must be available to start the database with the right parameters, and the datafiles must be in the location matching the control file. The redo logs and control file will be rebuilt.
9. Which of the following descriptions best describes incomplete recovery?
(Choose all that apply.)
A. Recovery that stops before the failure
B. Recovery that stops at the point of failure
C. Recovery that is missing transactions
D. Recovery that is not missing transactions
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Ans: A, C.
Incomplete recovery is a recovery that stops before the failure and a recovery
that is missing transactions. Incomplete recovery is not complete or missing some
data that was previously stored in the database prior to the failure.
10. What are the required steps to perform a RMAN-based incomplete recovery with the SET UNTIL TIME clause?
A. Start up the database in MOUNT mode, verify or set the NLS_DATE_FORMAT environment variable, designate time with the SET
UNTIL TIME time stamp, restore the necessary files with the RESTORE DATABASE command, recover the database with the RECOVER DATABASE command, and then open the database with the ALTER DATABASE OPEN
command.
B. Start up the database in NOMOUNT mode, verify or set the NLS_DATE_FORMAT environment variable, designate the SET UNTIL TIME time stamp, restore the necessary files with the RESTORE DATABASE command, recover the database with the RECOVER DATABASE command, and then open the database with the ALTER DATABASE OPEN
RESETLOGS command.
C. Start up the database in MOUNT mode, designate the SET UNTIL TIME time stamp, restore the necessary files with the RESTORE DATABASE command, recover the database with the RECOVER DATABASE command, and then open the database with ALTER DATABASE OPEN NORESETLOGS command.
D. Start up the database in MOUNT mode, verify or set the NLS_DATE_FORMAT environment variable, designate the SET UNTIL TIME time stamp, restore the necessary files with the RESTORE DATABASE command, recover the database with the RECOVER DATABASE command, and then open the database with ALTER DATABASE OPEN RESETLOGS command.
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Ans: D.
The proper process of performing a RMAN based incomplete recovery utilizing a
time stamp to determine the point-in-time to complete the recovery process is as
follows: Start up the database in MOUNT mode, verify or set the NLS_DATE_FORMAT
environment variable if not present, designate the SET UNTIL TIME time stamp,
restore the necessary files with the RESTORE DATABASE command, recover the
database with the RECOVER DATABASE command, and then open the database with
ALTER DATABASE OPEN RESETLOGS command.
11. Which command is not a valid RMAN incomplete recovery run block?
A. run
{
set until change 7563633;
restore database;
recover database;
}
B. run
{
set until time '06-SEP-2004 11:25:00';
restore database;
recover database;
}
C. run
{
set until SCN 7563633;
restore database;
recover database;
}
D. run
{
set until sequence 3 thread 1;
restore database;
recover database;
}
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Ans: A.
The SET UNTIL CHANGE command is not used with RMAN. This command is used during a user-managed incomplete recovery.
12. Which of the following would be a reason for using incomplete recovery?
(Choose all that apply.)
A. Stopping the recovery at a certain redo log sequence before a database corruption point
B. Stopping the recovery at a certain time when database corruption occurred
C. Stopping the recovery before a bad transaction is executed
D. Stopping the recovery only after applying all transactions
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Ans: A, B, C.
Incomplete recovery is designed to be able to stop at a desired point, before introducing undesired transactions to the database.
13. Which incomplete recovery capability is available to RMAN or user-managed methods?
A. SET UNTIL TIME
B. UNTIL TIME
C. UNTIL SCN
D. UNTIL SEQUENCE
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Ans: B.
The UNTIL TIME clause is available in both user-managed and RMAN-based incomplete recovery methods.
Note: the question should be 'RMAN and user-managed methods?'
14. When performing incomplete recovery, which command allows you to stop the recovery process at a random point?
A. UNTIL SEQUENCE, when performing a user-managed recovery
B. UNTIL SCN, when performing a RMAN-based recovery
C. UNTIL CANCEL, when performing a RMAN-based recovery
D. UNTIL CANCEL, when performing a user-managed recovery
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Ans: D.
The UNTIL CANCEL command is available only in user-managed recovery. This command allows you to stop the recovery process at a random point during redo log switches.
15. Which command is required when performing an incomplete recovery?
A. ALTER DATABASE OPEN RESETLOGS
B. ALTER DATABASE OPEN NORESETLOGS
C. UNTIL CANCEL
D. ALTER DATABASE OPEN
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Ans: A.
The ALTER DATABASE OPEN RESETLOGS command is required with every incomplete recovery. This is because the redo log sequence always needs to be reset.
16. When using EM to perform a whole database incomplete recovery, what sequence of events must occur? (Choose the best answer.)
A. The database must be shut down and started in NOMOUNT mode.
B. The database must be started in MOUNT mode.
C. The database must be shut down and started in MOUNT mode.
D. The database must be shut down and restarted.
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Ans: C.
When using EM, the database must be shut down and started in MOUNT mode so
that a whole database backup can be performed when you are recovering the same
database EM is connected to.
17. Which credentials are needed to perform a recovery with EM? (Choose all that apply.)
A. Database account with SYSDBA privilege
B. Administrator account in Windows
C. Oracle account in Unix
D. Any Windows account
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Ans: A, B, C.
You need two credentials when running a recovery with EM: the correct operating system account and the correct database account. The correct operating system account is an account similar to the Oracle account in Unix or the administrator account in Windows. The database account is any account that has SYSDBA privilege.
18. The RESETLOGS clause is required with which of the following types of incomplete recovery?
A. Using the UNTIL CANCEL command and applying almost all the archived redo logs before cancelling recovery
B. Using the UNTIL TIME command and stopping before the current time
C. Using the SET UNTIL SEQUENCE command and stopping before the last redo log sequence
D. All of the above
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Ans: D.
The RESETLOGS clause is required with all incomplete recovery options. The RESETLOGS clause is required because you are opening the database to a point prior to the existing redo log entries. So the redo logs must be reset when the database is opened.
19. What is required to perform a UNTIL SEQUENCE recovery in RMAN?
A. Identifying the sequence number with V$LOGHISTORY
B. Identifying the sequence number with V$LOG_HISTORY
C. Identifying the SCN number with V$LOG_HISTORY
D. Identifying the SCN number with V$LOGHISTORY
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Ans: B. You need to know the redo log sequence number and thread to perform an UNTIL SEQUENCE recovery in RMAN. This can be obtained by querying the V$LOG_HISTORY dynamic view.
20. What is required to recover your database through a RESETLOGS recovery from a backup created prior to the RESETLOGS recovery?
A. NORESETLOGS
B. RESETLOGS
C. UNTIL SEQUENCE
D. Nothing, this feature is automatic.
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Ans: D.
The new feature to recover your database through a prior RESETLOGS recovery is native with Oracle 10g. Oracle will recover the database through the RESETLOGS prior to recovery if necessary.
