Oracle: block change tracking

Block change tracking is used in conjunction with incremental backups. The block change tracking file, as you might imagine, is used to track the changes at the block level to each of the datafiles.

The block change tracking file size is automatically determined. It should be roughly 1/30,000 of the database size. The absolute minimum size is 320k per datafile so the file for my little database will be 5*320/1024 = 1.56 megs. The file will hold enough data to support 8 days of incremental backups. Your base backup, then, has to be done minimally, once a week.

1. To enable block change tracking:
   alter database enable block change tracking using
   using file '${absolute_path}' [ reuse ]
2. To disable block change tracking:
   alter database disable block change tracking
3. To identify status of block change tracking:
   

   SQL> select * from v$block_change_tracking;
   
   STATUS     FILENAME                                           BYTES
   ---------- --------------------------------------------- ----------
   DISABLED
   

   or

   SQL> select * from v$block_change_tracking;
   
   STATUS     FILENAME                                           BYTES
   ---------- --------------------------------------------- ----------
   ENABLED    /oracle/block_change/oci1_bc.fil                11599872