Recovering Databases with RMAN - OCP: Oracle Database 12c Administrator Certified Professional - page 214

What Can i Recover To?
You may want to make sure you can actually recover to the point in time that you are
interested in before you haul off and try the recovery. Nothing makes for a worse day
than trying to do a point-in-time restore, after having removed the existing data files,
and then finding out that you can't do the restore.
The RESTORE VALIDATE command can come in handy here. You can use this command
to make sure that all of the backup set pieces you will need to restore your database are
available, without actually restoring the database. This command checks both backup sets
for data file backups and archived redo logs as well as any data file image copies. Here is
an example of the RESTORE VALIDATE command for a point-in-time database recovery:
RMAN> restore database until time 'sysdate -1/24' validate;
Starting restore at 28-SEP-13
using channel ORA_DISK_1
channel ORA_DISK_1: starting validation of datafile backup set
channel ORA_DISK_1: reading from backup piece
C:\ORACLE\FAST_RECOVERY_AREA\ORCL\BACKUPSET\2013_09_28
\O1_MF_NNNDF_TAG20130928T185206_4G09OW7B_.BKP
channel ORA_DISK_1: piece
handle=C:\ORACLE\FAST_RECOVERY_AREA\ORCL\BACKUPSET\2013_09_28
\O1_MF_NNNDF_TAG20130928T185206_4G09OW7B_.BKP tag=TAG20130928T185206
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: validation complete, elapsed time: 00:00:25
Finished restore at 28-SEP-13
Point-in-Time Recovery Mechanics
Regardless of the type of point-in-time recovery you are going to do, the mechanics are the
same. During a point-in-time recovery, the database must be in MOUNT mode. There is
no online point-in-time recovery for an entire Oracle database (though RMAN does offer
tablespace point-in-time recovery, which can be done online).
Once the point-in-time recovery is complete, you will open the database with the ALTER
DATABASE OPEN RESETLOGS command. This will reset (or recreate if need be) the online redo
logs of the database and open it for business. The end result is a new incarnation of the data-
base (see Chapter 2 for more on database incarnations), which can impact future backups.
Oracle Database 12 c and RMAN will be able to use the same backup to restore the database
(as well as any old and new archived redo logs). Still, it's probably a good idea to perform
another backup of your database, because it just makes things cleaner and easier.