I will continue to tell you about the RMAN (Recovery Manager) tool in this seventh article of my tutorial series .
Read Older articles of my rman backup tutorial series before this article with following links.
Block Change Tracking: There is a serious performance problem in case of incremental backup. Because All datafiles are scanned and changing blocks are determined while taking a incremental backup. This performance problem has been fixed with Oracle 10g. With Oracle 10g, changed blocks are written to a file and this backup file is used in incremental backup, a significant performance increase has been achieved in this way. This file is called the Change Tracking File.
We can enable this feature as follows.
[oracle@MehmetSalih ~]$ sqlplus / as sysdba SQL*Plus: Release 188.8.131.52.0 - Production on Mon Mar 25 17:37:18 2019 Version 184.108.40.206.0 Copyright (c) 1982, 2018, Oracle. All rights reserved. Connected to: Oracle Database 19c Enterprise Edition Release 220.127.116.11.0 - Production Version 18.104.22.168.0 SQL> select status from v$block_change_tracking; STATUS ---------- DISABLED SQL> alter database enable block change tracking using file '/BACKUP/rman_change_tracking_file.f' reuse;
When we enable this feature as above, the blocks that are changed after Full backup will now be written to /BACKUP/rman_change_tracking_file.f. This means that when incremental backup is taken, RMAN should read this file instead of scanning all datafiles one by one. This means a significant performance gain for incremental backup operations. We can disable this feature with the following command.
SQL> ALTER DATABASE DISABLE BLOCK CHANGE TRACKING;