Block Change Tracking :
* Block Change Tracking Feature is used to speed up the RMAN incremental backup.
*After Enabling this feature the records modified since the last backup and log stored of it in a block change tracking file using the change
Tracking writer(CTWR) Process.
*Records modified since the last backup and stores log of it in the blcok change tracking file.
*During backup RMAN uses the logfile to identify the specific blocks that must be backedup.
*Block Change Tracking is not read the whole database blocks but only read the changed blocks which results in the block change tracking file.
*Block Change Tracking file is not read all the datafile blocks but read the changed blocks and take backups.
STEP 1:
Enable the Block Change Tracking Feature.
SQL>alter database enable block change tracking using file ‘/u02/prod/blockfile.log’
STEP 2:
Check the status of the enabled block change tracking file.
SQL>select file_name,status from v$block_change_tracking
STEP 3:
Check the Change Tracking writer (CTWR) is started.
SQL>select * from v$sgastat where name like %CTWR%
SQL>select sid,program,status from v$session where name like %CTWR%
STEP 4:
Disable the Block change Tracking Feature.
SQL>alter database disable block change tracking;
SQL>select sid,program,status from v$session where name like %CTWR%
