While doing a crash test that involved losing all the content of the ASM Disk Group Data, I noticed that a set of 3 transported tablespaces that was plugged in and left read only, were not part of the backup set.
When trying to execute alter database open resetlogs I've got:
ORA-01135: file n accessed for DML/query is offline
ORA-01110: data file n: '<plugged-in RO tablespace datafile>'
This problem has been described as affecting read only plugged in tablespaces. Rman silently excludes them from any backupset.
Workaround is implemented following these steps:
- Offline drop the datafiles comprising the plugged in read only tablespaces,
- Backup controlfile to trace, the script will exclude the readonly datafiles,
- Recreate the controlfile,
- Drop the tablespace of the offlined datafiles.
You may online these tablespaces and backup them using backup as copy, and then offline them again, if you need them to be offline.