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...Change Tracking
Block change recorded in a file
File size estimate 1/30,000 of db size
Caution
- Oracle doc mentions performance hit
- No specifics
- Must Test
Notes:
Change tracking is implemented by the creation of a file that records which blocks are changed. The Oracle documentation says that the initial size of the file is 10MB and grows in 10MB increments. The space required is 1/30,000 of the blocks tracked. The file size shown in the example above is roughly 10MB.
While the file size should not be an issue, Oracle does mention a performance hit related to the use of this feature. Test before implementing.
Refer to Chapter 4 of the Oracle10g Database Backup and Recovery Basics manual for more information on change tracking. Specifically, read the section entitled “Improving Incremental Backup Performance: Change Tracking.”
Supplemental Notes
Execute the following query to determine if change tracking is enabled for your database:
DAVE@linux3> select status from v$block_change_tracking;
STATUS
----------
ENABLED