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RMAN 11G : RMAN UNDO backup optimization [ID 406468.1]

原创 Linux操作系统 作者:spider0283 时间:2012-02-26 17:21:58 0 删除 编辑

In this Document
  Purpose
  Scope and Application
  RMAN 11G : RMAN UNDO backup optimization
  References


Applies to:

Oracle Server - Enterprise Edition - Version: 11.1.0.6 and later   [Release: 11.1 and later ]
Information in this document applies to any platform.

Purpose

RMAN 11G new feature : UNDO Backup Optimization

Scope and Application

Intended audience are DBA's who are supporting large databases and make backups via RMAN.
Common knowledge of RMAN is required.

RMAN 11G : RMAN UNDO backup optimization

In backup undo optimization, RMAN excludes undo not needed for recovery from the backup, that is, for transactions which have already been committed.  For example, a user updates the salaries table in the USERS tablespace. The change is written to the USERS tablespace, while the before image of the data is written to the UNDO tablespace. The user commits.  A subsequent RMAN backup of the UNDO tablespace does not include the undo information for the salary changes as a restore of this backup would already have the committed data. 

The undo excluded is based on commit of user and an internally specified period of time.  Backup undo optimization is built-in RMAN behavior. and cannot be disabled.  However, there are some restrictions:

- Compatible parameter must be set to 11.0 or higher 
- Backup must use a disk or OSB channel
- For 'backup copy of ' or 'backup datafilecopy' the database must be open for undo optimization to be used. 
- Not active for LEVEL 1 incremental backups, only for LEVEL 0 and FULL backups

 

RMAN> list backup of datafile 3;

List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
58 Full 73.10M DISK 00:00:29 14-JAN 00:07:00
BP Key: 69 Status: AVAILABLE Compressed: NO Tag: TAG20070114T000631
Piece Name: /backups/v110/V110_40i7ejo7_1_1
List of Datafiles in backup set 58
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------------- ----
3 Full 277406 14-JAN 00:06:31 /oradata/v110/undotbs01.dbf

RMAN> backup datafile 3;

Starting backup at 14-JAN 00:07:44
using channel ORA_DISK_1
using channel ORA_DISK_2
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00003 name=/oradata/v110/undotbs01.dbf
channel ORA_DISK_1: starting piece 1 at 14-JAN 00:07:45
channel ORA_DISK_1: finished piece 1 at 14-JAN 00:07:48
piece handle=/backups/v110/V110_44i7ejqh_1_1 tag=TAG20070114T000744 comment=NONEchannel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
Finished backup at 14-JAN 00:07:48

Starting Control File and SPFILE Autobackup at 14-JAN 00:07:48
piece handle=/backups/v110/V110_c-1689207191-20070114-01 comment=NONE
Finished Control File and SPFILE Autobackup at 14-JAN 00:07:50

RMAN> list backup of datafile 3;

List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
58 Full 73.10M DISK 00:00:29 14-JAN 00:07:00
BP Key: 69 Status: AVAILABLE Compressed: NO Tag: TAG20070114T000631
Piece Name: /backups/v110/V110_40i7ejo7_1_1
List of Datafiles in backup set 58
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------------- ----
3 Full 277406 14-JAN 00:06:31 /oradata/v110/undotbs01.dbf

BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
61 Full 12.60M DISK 00:00:02 14-JAN 00:07:47
BP Key: 72 Status: AVAILABLE Compressed: NO Tag: TAG20070114T000744
Piece Name: /backups/v110/V110_44i7ejqh_1_1
List of Datafiles in backup set 61
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------------- ----
3 Full 277477 14-JAN 00:07:45 /oradata/v110/undotbs01.dbf


BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
63 Full 536.00K DISK 00:00:01 14-JAN 00:51:05
BP Key: 74 Status: AVAILABLE Compressed: NO Tag: TAG20070114T005104
Piece Name: /backups/v110/V110_46i7embo_1_1
List of Datafiles in backup set 63
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------------- ----
3 Full 278620 14-JAN 00:51:04 /oradata/v110/undotbs01.dbf




References

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