RMAN Restore and Recovery - Oracle RMAN for Absolute Beginners - page 171

■ For a complete description of all possible spfile and control file restore scenarios, see RMAN Recipes for
Oracle Database 12c .

Note

Incomplete Recovery
The term incomplete database recovery means that you can't recover all committed transactions. Incomplete means that
you do not apply all redo to restore up to the point of the last committed transaction that occurred in your database.
In other words, you are restoring and recovering to a point in time in the past. For this reason, incomplete database
recovery is also called database point-in-time recovery (DBPITR). Typically, you perform incomplete database recovery
for one of the following reasons:

• You don't have all the redo required to perform a complete recovery. You're missing either the

archived redo log files or the online redo log files that are required for complete recovery. This
situation could arise because the required redo files are damaged or missing.

• You purposely want to roll back the database to a point in time in the past. For example, you

would do this if somebody accidentally truncated a table, and you intentionally wanted to roll
back the database to just before the truncate table command was issued.

Incomplete database recovery consists of two : restore and recovery. The restore step re-creates data files, and
the recover step applies redo up to the specified point in time. The restore process can be initiated from RMAN in a
couple of different ways:

•

RESTORE DATABASE UNTIL

FLASHBACK DATABASE
For the majority of incomplete database recovery circumstances, you use the RESTORE DATABASE UNTIL
command to instruct RMAN to retrieve data files from the RMAN backup files. This type of incomplete database
recovery is the main focus of this section of the chapter. The Flashback Database feature is covered in the section
“Flashing Back a Database,” later in this chapter.
The UNTIL portion of the RESTORE DATABASE command instructs RMAN to retrieve data files from a point in time
in the past, based on one of the following methods:

•

• Time

• SCN

• Log sequence number

• Restore point

The RMAN RESTORE DATABASE UNTIL command will retrieve all data files from the most recent backup set or
image copy. RMAN will automatically determine from the UNTIL clause which backup set contains the required data
files. If you omit the UNTIL clause of the RESTORE DATABASE command, RMAN will retrieve data files from the latest
available backup set or image copy. In some situations this may be the behavior you desire. I recommend that you use
the UNTIL clause to ensure that RMAN restores from the correct backup set. When you issue the RESTORE DATABASE
UNTIL command, RMAN will establish how to extract the data files from any of the following types of backups:
Full database backup •

• Incremental level-0 backup

• Image copy backup generated by the

BACKUP AS COPY command