Backup and Recovery - Expert Consolidation in Oracle Database 12c - page 390

Issue the “create catalog” command next to start the creation of the catalog which will take a short while to
complete. Oracle 11g introduced a new feature, called a virtual private catalog. Such a virtual private catalog allows
the main catalog owner-“rco” in the example-to grant access to specific objects in the basic catalog. The idea is
to allow for stricter separation of duties. After all, in many enterprises dedicated teams are responsible for the
operational support of databases, and do not necessarily include the task of managing backup and recovery. The
virtual catalog allows the base catalog owner to logically subdivide the main catalog into smaller units. So instead of
connecting as the base catalog owner each time, you can create additional accounts in the database, and grant them
access to specific objects in the main catalog. The risk of these users to accidentally cause damage to the main catalog
is reduced, and access to databases is granted on a need-to-have basis only. The following examples however do not
use virtual catalogs, but instead focus on a base catalog instead which is probably the most widely used adoption of
RMAN catalogs.
Registering databases in the catalog
When using the RMAN catalog database you should connect to the catalog database as well as the target database
when taking backups. Before you can make use of the catalog however the target database(s) must be registered with
it. Using the rman utility again connect to the target database as the catalog database to register the database as shown:
[oracle@server1 ~]$ rman catalog rco@rcat target sys@cdb1
Recovery Manager: Release 12.1.0.1.0 - Production on Sat Sep 21 23:22:18 2013
Copyright (c) 1982, 2013, Oracle and/or its affiliates. All rights reserved.
target database Password:
connected to target database: CDB1 (DBID=800340993)
recovery catalog database Password:
connected to recovery catalog database
RMAN> register database;
database registered in recovery catalog
starting full resync of recovery catalog
full resync complete
The implicit resynchronization operation will ensure that existing backup information stored in the database's
controlfile is transferred into the recovery catalog.
Keeping controlfile and catalog in sync
Typically when you are taking backups you are connected to the recovery catalog database as well as the target
database. In certain circumstances however, it might not be possible to establish a connection to the recovery catalog
database for all the reasons DBAs know. In other environments, you may find yourself generating lots and lots of
redo log switches between backups. In both the foregoing cases it might be necessary to manually resynchronize the
catalog. This operation is simple and can be performed quickly by issuing the following command when connected to
the target database and catalog:
RMAN> resync catalog;
As soon as you start paying attention to the RMAN output when using the catalog you will see that the
resynchronization happens fairly frequently.