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Question and Answer

Connor McDonald

Thanks for the question, Asim Amitav.

Asked: February 13, 2017 - 11:06 am UTC

Last updated: February 20, 2017 - 2:24 am UTC

Version: 11.2.0.4

Viewed 1000+ times

You Asked

Hi ,

If block change tracking is ENABLED, Does oracle uses this file when we take an offline incremental backup ( in mount mode ) ?
As the Db is not open , I think it can not access the file ( change tracking file), I believe the feature is only helpful for online incremental backup.

Thanks
Asim A

and Connor said...

Block change tracking is possible for offline as well.

Example (I have block change tracking enabled already)

--
-- First level 1, takes a couple of minutes
--
RMAN> backup incremental level 1 database format 'c:\temp\bkp%U';

Starting backup at 20/02/2017-10:14:36
using channel ORA_DISK_1
no parent backup or copy of datafile 4 found
no parent backup or copy of datafile 2 found
no parent backup or copy of datafile 1 found
no parent backup or copy of datafile 5 found
channel ORA_DISK_1: starting incremental level 0 datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00004 name=C:\ORACLE\ORADATA\DB11\USERS01.DBF
input datafile file number=00002 name=C:\ORACLE\ORADATA\DB11\SYSAUX01.DBF
input datafile file number=00001 name=C:\ORACLE\ORADATA\DB11\SYSTEM01.DBF
input datafile file number=00005 name=C:\ORACLE\ORADATA\DB11\EXAMPLE01.DBF
channel ORA_DISK_1: starting piece 1 at 20/02/2017-10:14:37
channel ORA_DISK_1: finished piece 1 at 20/02/2017-10:15:52
piece handle=C:\TEMP\BKP0SRT1S8D_1_1 tag=TAG20170220T101437 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:01:15
channel ORA_DISK_1: starting incremental level 1 datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00003 name=C:\ORACLE\ORADATA\DB11\USERS_MV01.DBF
input datafile file number=00006 name=C:\ORACLE\ORADATA\DB11\UNDOTMP.DBF
channel ORA_DISK_1: starting piece 1 at 20/02/2017-10:15:52
channel ORA_DISK_1: finished piece 1 at 20/02/2017-10:16:47
piece handle=C:\TEMP\BKP0TRT1SAO_1_1 tag=TAG20170220T101437 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:55
Finished backup at 20/02/2017-10:16:47

--
-- Next level 1, is almost instant (due to BCT)
--
RMAN> backup incremental level 1 database format 'c:\temp\bkp%U';

Starting backup at 20/02/2017-10:17:19
using channel ORA_DISK_1
channel ORA_DISK_1: starting incremental level 1 datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00004 name=C:\ORACLE\ORADATA\DB11\USERS01.DBF
input datafile file number=00002 name=C:\ORACLE\ORADATA\DB11\SYSAUX01.DBF
input datafile file number=00003 name=C:\ORACLE\ORADATA\DB11\USERS_MV01.DBF
input datafile file number=00006 name=C:\ORACLE\ORADATA\DB11\UNDOTMP.DBF
input datafile file number=00001 name=C:\ORACLE\ORADATA\DB11\SYSTEM01.DBF
input datafile file number=00005 name=C:\ORACLE\ORADATA\DB11\EXAMPLE01.DBF
channel ORA_DISK_1: starting piece 1 at 20/02/2017-10:17:20
channel ORA_DISK_1: finished piece 1 at 20/02/2017-10:17:21
piece handle=C:\TEMP\BKP0VRT1SDG_1_1 tag=TAG20170220T101720 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 20/02/2017-10:17:21

--
-- Now I take database to mount mode
--
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
sys@db11
SQL> startup mount
ORACLE instance started.

Total System Global Area 3206836224 bytes
Fixed Size                  2285512 bytes
Variable Size             788529208 bytes
Database Buffers         2399141888 bytes
Redo Buffers               16879616 bytes
Database mounted.

--
--  Still super fast
--
RMAN>  backup incremental level 1 database format 'c:\temp\bkp%U';

Starting backup at 20/02/2017-10:19:26
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=129 device type=DISK
channel ORA_DISK_1: starting incremental level 1 datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00004 name=C:\ORACLE\ORADATA\DB11\USERS01.DBF
input datafile file number=00002 name=C:\ORACLE\ORADATA\DB11\SYSAUX01.DBF
input datafile file number=00003 name=C:\ORACLE\ORADATA\DB11\USERS_MV01.DBF
input datafile file number=00006 name=C:\ORACLE\ORADATA\DB11\UNDOTMP.DBF
input datafile file number=00001 name=C:\ORACLE\ORADATA\DB11\SYSTEM01.DBF
input datafile file number=00005 name=C:\ORACLE\ORADATA\DB11\EXAMPLE01.DBF
channel ORA_DISK_1: starting piece 1 at 20/02/2017-10:19:26
channel ORA_DISK_1: finished piece 1 at 20/02/2017-10:19:27
piece handle=C:\TEMP\BKP11RT1SHE_1_1 tag=TAG20170220T101926 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 20/02/2017-10:19:27

--
-- And now I ditch BCT altogether
--
SQL> ALTER DATABASE DISABLE BLOCK CHANGE TRACKING;

Database altered.

--
-- and the incremental takes a lot longer
--
RMAN> backup incremental level 1 database format 'c:\temp\bkp%U';

Starting backup at 20/02/2017-10:21:03
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=69 device type=DISK
channel ORA_DISK_1: starting incremental level 1 datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00004 name=C:\ORACLE\ORADATA\DB11\USERS01.DBF
input datafile file number=00002 name=C:\ORACLE\ORADATA\DB11\SYSAUX01.DBF
input datafile file number=00003 name=C:\ORACLE\ORADATA\DB11\USERS_MV01.DBF
input datafile file number=00006 name=C:\ORACLE\ORADATA\DB11\UNDOTMP.DBF
input datafile file number=00001 name=C:\ORACLE\ORADATA\DB11\SYSTEM01.DBF
input datafile file number=00005 name=C:\ORACLE\ORADATA\DB11\EXAMPLE01.DBF
channel ORA_DISK_1: starting piece 1 at 20/02/2017-10:21:04
channel ORA_DISK_1: finished piece 1 at 20/02/2017-10:21:49
piece handle=C:\TEMP\BKP13RT1SKG_1_1 tag=TAG20170220T102103 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:45
Finished backup at 20/02/2017-10:21:49




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