How to get list of backed up data files from RMAN catalogue schema

To get a list of datafiles with sizes in Kb for the current incarnation of a database (in this
example TESTDB) directly from RMAN catalogue database - login as the catalogue schema owner
and run the query below:

select d.NAME || ',' || d.BYTES/1024 as name_kb
from RC_DATAFILE d, RC_DATABASE_INCARNATION i
where d.DB_NAME = 'TESTDB'
and d.DB_KEY    = i.DB_KEY
and d.DBINC_KEY = i.DBINC_KEY
and d.DB_NAME   = i.NAME
and i.CURRENT_INCARNATION = 'YES'
order by d.BYTES desc;

To get a list of online redo logs run the following sql query:

select rr.name
from rc_redo_log rr, rc_database rdb
where rr.db_name = rdb.name
and rr.dbinc_key = rdb.dbinc_key
and rr.db_key = rdb.db_key
and rr.db_name = 'TESTDB';