You can increase the incremental backup speed with Block Change Tracking, which is one of the features that introduced with 10G.
When we enable this feature, backups are taken without checking the changing blocks. This means a very serious time saving.
The tracking of changing blocks is done with the Change Tracking Writer (CTWR) background process.
When Block Change Tracking is activated, the CTWR process will also start.
When a commit operation occurs, the block change information is copied into the field called CTWR buffer in the large pool.
In the Checkpoint process, the CTWR process writes the information in the CTWR buffer area to the change tracking file we specified when BCT was activated.
Based on my experience, a backup process time of 11 hours can be reduced to 50 minutes.
To use this feature, you need to activate it as follows. The “REUSE” statement in the command allows us to reuse the file if it was previously used.
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SQL> ALTER DATABASE ENABLE BLOCK CHANGE TRACKING USING FILE '+RECO/ORCL/block_change_tracking.dat' REUSE; Database altered. |
The following query can be used to query the current status.
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SQL> SELECT status, filename FROM V$BLOCK_CHANGE_TRACKING; STATUS ------------------------------ FILENAME -------------------------------------------------------------------------------- ENABLED +RECO/orcl/block_change_tracking.dat |
To disable this feature, the following command will be sufficient.
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SQL> alter database disable block change tracking; Database altered. |
