Databases Reference
In-Depth Information
How It Works
It's important to synchronize the secondary recovery catalog manually on a frequent basis so the catalog remains
current. This way, when you are forced to fall back on the secondary catalog, it'll have all the backup metadata you need.
You must back up the secondary recovery catalog database just as you would the primary catalog database to
provide high availability.
Viewing Backup Information
Problem
You want to access information stored in the recovery catalog. You know you can use the database views in the
individual target databases to find out information about their backups, but you'd like to get data about all your
target databases from the recovery catalog itself.
Solution
The recovery catalog comes with its own special set of dynamic views that are analogous to the database performance
views (V$ views). These recovery catalog views have the prefix RC_. Each such recovery catalog view contains
information for all the target databases registered in the recovery catalog.
Most of the RC_ views use the DB_KEY column to uniquely identify a target database registered in the recovery
catalog. That is, the DB_KEY column is the primary key in each of the recovery catalog views or RC_ views. To obtain
the DB_KEY for a database, first identify the DBID for that database. Each DBID is mapped to a unique database and
is connected to a single DB_KEY value. You can find out the DBID of a database with the following query:
RMAN> connect target orcl
target database Password:
connected to target database: ORCL (DBID=1316762630)
RMAN> select DBID from v$database;
DBID
----------
1316762630
RMAN>
Once you have the DBID for a database, you can get the DB_KEY from the RC_DATABASE view after first
connecting to the recovery catalog database:
SQL> connect rman/rman@catdb
SQL> select db_key from rc_database where dbid = 1316762630;
DB_KEY
----------
501
SQL>
