Which three statements are true about using flashback database in a multitenant container
database (CDB)?
A.
The root container can be flashed back without flashing back the pluggable databases (PDBs).
B.
To enable flashback database, the CDB must be mounted.
C.
Individual PDBs can be flashed back without flashing back the entire CDB.
D.
The DB_FLASHBACK RETENTION_TARGET parameter must be set to enable flashback of
the CDB.
E.
A CDB can be flashed back specifying the desired target point in time or an SCN, but not a
restore point.
Explanation:
C: * RMAN provides support for point-in-time recovery for one or more pluggable
databases (PDBs). The process of performing recovery is similar to that of DBPITR. You use the
RECOVER command to perform point-in-time recovery of one or more PDBs. However, to recover
PDBs, you must connect to the root as a user with SYSDBA or SYSBACKUP privilege
D: DB_FLASHBACK_RETENTION_TARGET specifies the upper limit (in minutes) on how far
back in time the database may be flashed back. How far back one can flashback a database
depends on how much flashback data Oracle has kept in the flash recovery area.Range of values0 to 231 – 1
Note:
Reference; Oracle Database, Backup and Recovery User’s Guide 12c
Correct options are BDE. C-Option is not correct.
CDB must be mounted to perform Flashback Database.
Flashback can be done only at CDB level and this will apply to all containers, the root and the PDBs
I think answer is ‘BCD’
BDE is correct sequence.
Correct Answer: BDE
Flashback database
doesn’t work in PDB’s:
RMAN> flashback pluggable database pdb1 to time “to_date(’23:15 02-03-2014′,’hh24:mi dd-mm-yyyy’)”;
Starting flashback at 02-MAR-14 using channel ORA_DISK_1
using channel ORA_DISK_2
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of flashback command at 02/03/2014 23:20:45
RMAN-05108: Command is not supported for pluggable database by Johan R
Thank you! JRD
Well, E isn’t right either. Try this:
SQL> create restore point x;
Restore point created.
SQL> flashback database to restore point x;
Flashback complete.
D is questionable as well, as you can just use the default DB_FLASHBACK RETENTION_TARGET value.
So, as far as I’m concerned, the only correct answer is [B] (and maybe [D] is you’re pushing it).
BCD
Hi @ll,
sry but NO answer is correct?!?!
A: BR operations only on cdb level (Sunil is right!)
B: flashback can be enabled in 12c in OPEN and mount mode … so the MUST not be in mount mode … it may be in mounted or open mode …
C: already described by jrd .. -> yes right!
D: must not be explicitly set, default 1440 is ok. Further it can be 0 and flashback is possible ..> this is optional!
E: restore points are possible. (see Shawn’s comment)
So what should we answer!?
I agree with gumpx.
– Flashback can be enabled when database is either mount or open.
– The Oracle doc says that the DB_FLASHBACK_RETENTION_TARGET can optionnaly be set since it has a default value.
– Restore points are supported…
I would say this question is outdated!
The given answer, CDE, is wrong. In fact, ALL the statements in the question are incorrect.
A: Flashback database occurs at the CDB level. If the CDB is flashed back, then so too are all the PDBs it contains.
B: This is misleading. You can enable/disable flashback database when the database is mounted or open by using ALTER DATABASE FLASHBACK ON|OFF. To say the database “must” be mounted implies that’s the state the database must be in, in order to enable Flashback Database – which is not true, because you can enable/disable it when the database is open. Now, you could make the argument that an open database is mounted by definition, but in Oracle parlance, the state of the database is either NOMOUNT, MOUNT or OPEN. So B is wrong.
C: Flashback Database occurs at the CDB level, not the PDB level.
D: This is misleading. The word “must” is the sticking point. It implies YOU must set DB_FLASHBACK_RETENTION_TARGET in order to enable Flashback Database which is not true because this parameter has a default value, 1440 which is specified in minutes.
E: You can flashback a database to a specific timestamp, SCN or a named restore point.
So none of the question’s statements are true.
H*T*H
Perform Flashback for a CDB It is possible to perform Flashback Database Operations on a CDB as you would on a non-CDB.
If it is necessary to flashback the CDB to a point earlier than the DBPITR of the PDB, you must perform the following steps: Start RMAN and connect to the root as a user with the SYSBACKUP or SYSDBA privilege. Determine the target time to which the CDB must be recovered. Take all files that correspond to the PDB for which PITR was performed offline. Rewind the CDB to the desired target time. The PDB whose files are offline will not be affected. Recover the PDB for which PITR was performed using the RESTORE PLUGGABLE DATABASE and RECOVER PLUGGABLE DATABASE commands.
Morris, Matthew (2014-03-20). Study Guide for 1Z0-060: Upgrade to Oracle Database 12c: Oracle Certification Prep (p. 61). ODB Press. Kindle Edition.
In order to enable Flashback Database, you must first ensure the database instance is open or mounted. If the instance is mounted, then the database must
be shut down cleanly unless it is a physical standby database. Optionally, set the DB_FLASHBACK_RETENTION_TARGET to the length of the desired flashback window in minutes. The default is 1 day (1440 minutes). Enable the Flashback Database feature for the whole database: ALTER DATABASE FLASHBACK ON;
Morris, Matthew (2014-03-20). Study Guide for 1Z0-060: Upgrade to Oracle Database 12c: Oracle Certification Prep (p. 184). ODB Press. Kindle Edition.
https://docs.oracle.com/database/121/BRADV/rcmflash.htm#BRADV89739
“To enable logging for Flashback Database, you must set the DB_FLASHBACK_RETENTION_TARGET initialization parameter and issue the ALTER DATABASE FLASHBACK ON statement.” My comment: even if there is a default value DB_FLASHBACK_RETENTION_TARGET must be set (must not be empty). so D is correct.
B is not correct.
C is not correct (RMAN-05108: Command is not supported for pluggable database).
So correct answers are
A D E
ABD I would go for ABD
wrong E
Performing a Flashback Database Operation
This section presents a basic technique for performing a flashback of the database, specifying the desired target point in time with a time expression, the name of a normal or guaranteed restore point, or an SCN.
FLASHBACK DATABASE TO SCN 46963;
FLASHBACK DATABASE TO RESTORE POINT BEFORE_CHANGES;
FLASHBACK DATABASE TO TIME “TO_DATE(’09/20/12′,’MM/DD/YY’)”;
Idea: Perhaps B is :’To flashback a database, the CDB must be mounted.’ => this would be correct!
Idea: Perhaps B is :’To enable flashback database, the CDB must be mounted or opened.’
wrong C
In Oracle 12.1 flashback database is NOT possible at PDB level. It’s planned for 12.2
A&B&D
Example: Rewinding a CDB to a Point that is Beyond the Point in Time to Which a PDB Was Recovered
Assume that a CDB contains the following PDBs: pdb1, pdb2, pdb3, and pdb4. DBPITR was performed on pdb2 and this PDB was opened with the RESETLOGS option when the SCN was 128756. You can perform a flashback of the whole CDB to a point in time when the SCN is greater than 128756. However, you cannot directly perform a flashback of the whole CDB to a point when the SCN is lower than 128756. Use the following steps to flashback the whole CDB to a point in time when the SCN was 128048:
Connect to the root as a user with the SYSDBA or SYSBACKUP privilege.
See Also:
“Making RMAN Connections to a CDB”
Determine the target time to which a Flashback Database operation must be performed on the CDB.
In this example, the target time is the time when the SCN was 128048.
Take all the files corresponding to pdb2 offline using the following command:
ALTER PLUGGABLE DATABASE PDB2 DATAFILE ALL OFFLINE;
Shut down the CDB and bring it to a mounted state as follows:
SHUTDOWN;
STARTUP MOUNT;
Rewind the CDB to the desired point in time.
The following command performs a flashback of the whole CDB to the point when the SCN was 128048.
FLASHBACK DATABASE TO SCN 128048;
Make the CDB available for updates by opening the CDB with the RESETLOGS option.
Open the CDB as follows:
ALTER DATABASE OPEN RESETLOGS;
Restore and recover the PDB pdb2. This includes restoring the PDB, making its file online, and then performing a complete recovery of the PDB.
The following commands restore and recover pdb2 and then open this PDB:
RESTORE PLUGGABLE DATABASE PDB2;
ALTER PLUGGABLE DATABASE PDB2 DATAFILE ALL ONLINE;
RECOVER PLUGGABLE DATABASE PDB2;
ALTER PLUGGABLE DATABASE PDB2 OPEN;
ABD
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BDE