Re-synchronization of the Recovery Catalog

                  Re-synchronization of the Recovery Catalog 

Changes made to the target database aren't automatically propagated to recovery catalog. "Backup" and "Copy" commands automatically perform a re-synchronization each time they run.

Manual re-synchronization required in following circumstances:-

1) When target database has just undergone a number of physical changes 

2) When the target database is performing a very large number of log switches in-between the              backups. 

Re-sync. Operation:-

RMAN reads the target database's control file to update information it keeps regarding datafiles, log switches, physical schema etc.

RMAN> RESYNC CATALOG;