Change Tracking Incremental Backups

RMAN's change tracking feature for incremental backups improves incremental backup performance by recording changed blocks in each datafile in a change tracking file.

If change tracking is enabled, RMAN uses the change tracking file to identify changed blocks for incremental backups, thus avoiding the need to scan every block in the datafile.

By default this is turned off, due to a very small performance overhead. When enabled the change tracking file is created as a Oracle Managed File in the DB_CREATEFILE_DEST location. You can choose to name the file your self and place it anywhere.

Enabling Change Tracking:

--Database must be mounted or open

SQL> alter database enable block change tracking;
--or name the file yourself
SQL>alter database enable block change tracking
USING FILE '/u01/app/oracle/rman_change_track.f'
REUSE;

Checking if change tracking is enabled:

SQL> select * from v$block_change_tracking;

STATUS FILENAME BYTES
---------- --------------------------------------------- -----
ENABLED +DATA/prod/changetracking/ctf.267.664766903 11599

Disable block change tracking:

SQL> alter database disable block change tracking;

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keywords: change tracking
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rdbms version: 10g - 11g
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