Make backupset unavailable in RMAN

This may be useful when you want to restore archive logs which were backed up more than once.
These archivelog files will be included in multiple backup sets in the RMAN catalog, by
default it will attempt to restore from the latest backup. But what if at the moment you have
tapes from earlier backup, or one of the files got corrupted and the latest backup has the
corrupted version? Here's what you do:

. oraenv
ORACLE_SID

rman

RMAN> connect target;

RMAN> connect catalog rman/password@CATDB;

RMAN> list backup of archivelog from logseq = 124349 until logseq = 124449;


List of Backup Sets
===================

BS Key  Size       Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
5447    665M       SBT_TAPE    00:03:35     12-JUL-07      
        BP Key: 6468   Status: AVAILABLE  Compressed: NO  Tag: TAG20070712T224403
        Handle: /DBNAME.ARC.roimm89p_1_1/   Media: PCC401

  List of Archived Logs in backup set 5447
  Thrd Seq     Low SCN    Low Time  Next SCN   Next Time
  ---- ------- ---------- --------- ---------- ---------
  1    124413  7338072204478 12-JUL-07 7338072246322 12-JUL-07
  1    124414  7338072246322 12-JUL-07 7338072294914 12-JUL-07
  1    124415  7338072294914 12-JUL-07 7338072328638 12-JUL-07
  1    124416  7338072328638 12-JUL-07 7338072373031 12-JUL-07
  1    124417  7338072373031 12-JUL-07 7338072443931 12-JUL-07
  1    124418  7338072443931 12-JUL-07 7338072482427 12-JUL-07
  1    124419  7338072482427 12-JUL-07 7338072528575 12-JUL-07

BS Key  Size       Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
5461    95M        SBT_TAPE    00:04:55     12-JUL-07      
        BP Key: 6482   Status: AVAILABLE  Compressed: NO  Tag: TAG20070712T224403
        Handle: /DBNAME.ARC.s3imm8i4_1_1/   Media: PCC524

  List of Archived Logs in backup set 5461
  Thrd Seq     Low SCN    Low Time  Next SCN   Next Time
  ---- ------- ---------- --------- ---------- ---------
  1    124349  7338033789154 12-JUL-07 7338033816533 12-JUL-07


....


BS Key  Size       Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
38474   285M       SBT_TAPE    00:01:14     24-JUL-07      
        BP Key: 38614   Status: AVAILABLE  Compressed: NO  Tag: TAG20070724T091359
        Handle: /DBNAME.ARC.m9inkdob_1_1/   Media: PCC828


RMAN> change backupset 38474 unavailable;

changed backup piece unavailable
backup piece handle=/DBNAME.ARC.m9inkdob_1_1/ recid=109056 stamp=628766476
Changed 1 objects to UNAVAILABLE status


The completion time for backupset 38474 is 24-JUL-07 and the other backupsets completed on
12-JUL-07, in this case I want to restore from backup that took place on 12-JUL-07 so I made
the other backupset unavailable, and those tapes will not be used to restore archived log
files.