RMAN-20512: source database already registered in recovery catalog
Source database was already registered in the recovery catalog.
If the source database is really registered, there is no need to
register it again. Note that the recovery catalog enforces that all
databases have a unique DBID. If the new database was created by copying
files from an existing database, it will have the same DBID as the
original database and cannot be registered in the same recovery catalog.