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that you will have to keep the backups of that read-only tablespace. This can sometimes be
troublesome over the long term. So the message here is to make tablespaces read-only only
after you figure out where and how you will store your backups.
The
RESTORE DATABASE
,
TABLESPACE
, and
DATAFILE
commands will restore read-only
tablespaces as required.
If you have read-only tablespaces and you have enabled RMAN optimiza-
tion so that they are only backed up once, you need to make sure that the
backups of those tablespaces don't accidently get deleted. While RMAN is
not going to delete them, a human might. Also it's possible that the media
management software that controls the media where the backup files are
stored will have its own retention criteria. It's no fun to try to restore a
tablespace from a backup file that isn't available.
Recovering a Database Using
Incomplete Recovery
We discussed
incomplete recovery
or
point-in-time recovery
back in Chapter 3. It is, essen-
tially, restoring the database to some point in time that is not the current point in time. If
you are not familiar with what incomplete recovery is, please review Chapter 3 for more
details. In the following sections, we will discuss point-in-time recoveries. First, we will
discuss the types of recoveries that are available, and then we will discuss the mechanics of
such recoveries.
Remember that point-in-time backups must be consistent. That means
you have to restore the whole database to the specific point in time
you are aiming for. Oracle offers the ability to do tablespace point-in-
time recoveries, which we will discuss in Chapter 7, “Performing Oracle
Advanced Recovery.”
Types of Point-in-Time Recovery
RMAN supports point-in-time recovery using the
UNTIL
clause of the
RESTORE
and
RECOVER
commands as shown in this example, where we will be restoring to 9/30/2013
at 18:00 hours:
Restore database until time '09/30/2013:18:00:00';
Recover database until time '09/30/2013:18:00:00';
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