如何从自动备份中恢复控制文件和SPFILE文件

启用了自动控制文件备份功能之后，在数据库发生重要改变或备份完成之后，会自动进行控制文件备份，同时备份SPFILE文件。
关于何时进行自动备份，Oracle如下说明:

When RMAN Performs Control File Autobackups

By default, control file autobackups are turned off, and no control file 
autobackups are performed. If CONFIGURE CONTROLFILE AUTOBACKUP is ON, 
then RMAN automatically backs up the control file and the current server 
parameter file (if used to start up the database) in one of two circumstances:
 

when a successful backup must be recorded in the RMAN repository, 
and when a structural change to the database affects the contents of the 
control file which therefore must be backed up.

以下示例用于说明如何通过自动备份恢复控制文件和SPFILE文件。
1.查询当前拥有的备份

$ rman target /

Recovery Manager: Release 10.1.0.2.0 - 64bit Production

Copyright (c) 1995, 2004, Oracle.  All rights reserved.

connected to target database: EYGLE (DBID=1337390772)

RMAN> list backup of controlfile;

using target database controlfile instead of recovery catalog

List of Backup Sets
===================

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
26      Full    3M         DISK        00:00:02     29-MAR-05      
        BP Key: 26   Status: AVAILABLE  Compressed: NO  Tag: TAG20050329T171049
        Piece Name: /data5/flash_recovery_area/EYGLE/autobackup/2005_03_29/o1_mf_s_554231449_14l6wv59_.bkp
  Controlfile Included: Ckp SCN: 10643029     Ckp time: 29-MAR-05

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
27      Full    3M         DISK        00:00:02     29-MAR-05      
        BP Key: 27   Status: AVAILABLE  Compressed: NO  Tag: TAG20050329T222158
        Piece Name: /data5/flash_recovery_area/EYGLE/autobackup/2005_03_29/o1_mf_s_554250117_14ls48bd_.bkp
  Controlfile Included: Ckp SCN: 10652118     Ckp time: 29-MAR-05

2.从备份中恢复控制文件

RMAN> restore controlfile to '/tmp/control.ctl' from 
'/data5/flash_recovery_area/EYGLE/autobackup/2005_03_29/o1_mf_s_554250117_14ls48bd_.bkp';

Starting restore at 30-MAR-05
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=134 devtype=DISK

channel ORA_DISK_1: restoring controlfile
channel ORA_DISK_1: restore complete
Finished restore at 30-MAR-05

3.从备份中恢复SPFILE文件

RMAN> restore spfile to '/tmp/spfileeygle.ora' from 
'/data5/flash_recovery_area/EYGLE/autobackup/2005_03_29/o1_mf_s_554250117_14ls48bd_.bkp';

Starting restore at 30-MAR-05
using channel ORA_DISK_1

channel ORA_DISK_1: autobackup found: 
/data5/flash_recovery_area/EYGLE/autobackup/2005_03_29/o1_mf_s_554250117_14ls48bd_.bkp
channel ORA_DISK_1: SPFILE restore from autobackup complete
Finished restore at 30-MAR-05

RMAN>