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Tuesday, February 9, 2016

Block change tracking for faster Incremental RMAN backups

The details of changes in the blocks of the database after the last backup are written in the block change tracking file.RMAN uses this file for tracking the changed block and backup it instead all the blocks and hence saves time and space.

The background process Block Change Tracking Writer (CTWR) will be writing modified block details to block change tracking file.

The Change Tracking file is read during backups and the required blocks are accessed directly.

To enable block change tracking 

alter database enable block change tracking using file '/u02/oracle/oradata/GOLD/block_change_track.dbf';

when using OMF we can enable block change tracking as follows

alter database enable block change tracking ;

the change tracking file will be created in the directory mentioned by DB_CREATE_FILE_DEST.

now check ,

col filename for a70
select filename,status from v$block_change_tracking;

-----------------------------------                          ---------------

To Disable

SQL>alter database disable block change tracking;

To Check

select status from V$BLOCK_CHANGE_TRACKING;

1 comment:

Sridevi K said...

Sridevi Koduru (Senior Oracle Apps Trainer
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Please Contact for One to One Online Training on Oracle Apps Technical, Financials, SCM, SQL, PL/SQL, D2K at | +91 - 9581017828.