官方说明：
You can apply RESTORE ... PREVIEW to any RESTORE operation to create a detailed list of every backup to be used in the requested RESTORE operation, and the necessary target SCN for recovery after the RESTORE operation is complete
. This command accesses the RMAN repository to query the backup metadata, but does not actually read the backup files to ensure that they can be restored.
上面大致说了两点:
1 restore
………preview命令
给出恢复restore操作所需要的备份文件列表。
2 restore
………preview命令实际上不读取备份文件以确认备份能够恢复。
二：restore database preview 显示结果
RMAN> restore database preview;
Starting restore at 22-NOV-12
using channel ORA_DISK_1
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
5 Full 568.48M DISK 00:00:58 20-NOV-12
BP Key: 5 Status: AVAILABLE Compressed: NO Tag: TAG20121120T084422
Piece Name: /backup/07nqp236_1_1
List of Datafiles in backup set 5
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
1 Full 2150426643 20-NOV-12 /oracle/CRM2/system1.dbf
2 Full 2150426643 20-NOV-12 /oracle/CRM2/zxb.dbf
3 Full 2150426643 20-NOV-12 /oracle/CRM2/CRM/sysaux01.dbf
4 Full 2150426643 20-NOV-12 /oracle/CRM2/CRM/users01.dbf
5 Full 2150426643 20-NOV-12 /oracle/CRM2/zxa.dbf
6 Full 2150426643 20-NOV-12 /oracle/CRM2/CRM/test1.dbf
7 Full 2150426643 20-NOV-12 /oracle/CRM2/zxc.dbf
8 Full 2150426643 20-NOV-12 /oracle/CRM2/CRM/undotbs1.dbf
List of Archived Log Copies
Key Thrd Seq S Low Time Name
------- ---- ------- - --------- ----
35 1 2 A 20-NOV-12 /oracle/archive/1_2_799830099.dbf
36 1 3 A 20-NOV-12 /oracle/archive/1_3_799830099.dbf
37 1 4 A 20-NOV-12 /oracle/archive/1_4_799830099.dbf
38 1 5 A 20-NOV-12 /oracle/archive/1_5_799830099.dbf
39 1 6 A 20-NOV-12 /oracle/archive/1_6_799830099.dbf
40 1 7 A 20-NOV-12 /oracle/archive/1_7_799830099.dbf
41 1 8 A 20-NOV-12 /oracle/archive/1_8_799830099.dbf
42 1 9 A 21-NOV-12 /oracle/archive/1_9_799830099.dbf
43 1 10 A 21-NOV-12 /oracle/archive/1_10_799830099.dbf
44 1 11 A 21-NOV-12 /oracle/archive/1_11_799830099.dbf
45 1 12 A 21-NOV-12 /oracle/archive/1_12_799830099.dbf
46 1 13 A 21-NOV-12 /oracle/archive/1_13_799830099.dbf
47 1 14 A 21-NOV-12 /oracle/archive/1_14_799830099.dbf
48 1 15 A 22-NOV-12 /oracle/archive/1_15_799830099.dbf
49 1 16 A 22-NOV-12 /oracle/archive/1_16_799830099.dbf
50 1 17 A 22-NOV-12 /oracle/archive/1_17_799830099.dbf
51 1 18 A 22-NOV-12 /oracle/archive/1_18_799830099.dbf
52 1 19 A 22-NOV-12 /oracle/archive/1_19_799830099.dbf
53 1 20 A 22-NOV-12 /oracle/archive/1_20_799830099.dbf
54 1 21 A 22-NOV-12 /oracle/archive/1_21_799830099.dbf
55 1 22 A 22-NOV-12 /oracle/archive/1_22_799830099.dbf
56 1 23 A 22-NOV-12 /oracle/archive/1_23_799830099.dbf
57 1 24 A 22-NOV-12 /oracle/archive/1_24_799830099.dbf
58 1 25 A 22-NOV-12 /oracle/archive/1_25_799830099.dbf
59 1 26 A 22-NOV-12 /oracle/archive/1_26_799830099.dbf
60 1 27 A 22-NOV-12 /oracle/archive/1_27_799830099.dbf
Media recovery start SCN is 2150426643
Recovery must be done beyond SCN 2150426643 to clear data files fuzziness
Finished restore at 22-NOV-12
----------------------------------------------------------------------------------------
对于上面的信息的一点解释：
介质恢复的开始是2150426643：Media recovery start SCN is 2150426643
以及开始应用的归档文件seq 号2：/oracle/archive/1_2_799830099.dbf
都是由restore database后,数据文件头部信息决定
，如下为转储数据文件头部信息：
Tablespace #2 - SYSAUX rel_fn:3
Creation at scn: 0x0000.00001896 10/22/2005 21:44:46
Backup taken at scn: 0x0000.00000000 01/01/1988 00:00:00 thread:0
reset logs count:0x2fac7053 scn: 0x0000.802c8c23 reset logs terminal rcv data:0x0 scn: 0x0000.00000000
prev reset logs count:0x2fac6f51 scn: 0x0000.802c3dfd prev reset logs terminal rcv data:0x0 scn: 0x0000.00000000
recovered at 11/22/2012 14:18:39
status:0x0 root dba:0x00000000 chkpt cnt: 1114 ctl cnt:1113
begin-hot-backup file size: 0
Checkpointed at scn: 0x0000.802ce813 11/20/2012 08:44:22 该scn值决定了数据文件恢复的起始 ( scn 0x802ce813转换10进制即为2150426643)
thread:1 rba:(0x2.eb3.10) 此处rba 0x2决定了应用归档开始的seq。
对于上面信息的一点误解：
由于列出来的归档seq号为2到27所以误以为recover会应用归档seq从 2到27，之后再应用current redo log直到其结尾。
三：跟踪recover恢复过程
而实际上recover database 恢复过程应用归档为2到22。
Restore database
后，通过查询视图v$recovery_log可查的恢复过程需要的归档seq为2-22号归档。.
SQL> select * from v$recovery_log;
THREAD# SEQUENCE# TIME ARCHIVE_NAME
---------- ---------- --------- ----------------------------------------
1 2 20-NOV-12 /oracle/archive/1_2_799830099.dbf
1 3 20-NOV-12 /oracle/archive/1_3_799830099.dbf
1 4 20-NOV-12 /oracle/archive/1_4_799830099.dbf
1 5 20-NOV-12 /oracle/archive/1_5_799830099.dbf
1 6 20-NOV-12 /oracle/archive/1_6_799830099.dbf
1 7 20-NOV-12 /oracle/archive/1_7_799830099.dbf
1 8 20-NOV-12 /oracle/archive/1_8_799830099.dbf
1 9 21-NOV-12 /oracle/archive/1_9_799830099.dbf
1 10 21-NOV-12 /oracle/archive/1_10_799830099.dbf
1 11 21-NOV-12 /oracle/archive/1_11_799830099.dbf
1 12 21-NOV-12 /oracle/archive/1_12_799830099.dbf
THREAD# SEQUENCE# TIME ARCHIVE_NAME
---------- ---------- --------- ----------------------------------------
1 13 21-NOV-12 /oracle/archive/1_13_799830099.dbf
1 14 21-NOV-12 /oracle/archive/1_14_799830099.dbf
1 15 22-NOV-12 /oracle/archive/1_15_799830099.dbf
1 16 22-NOV-12 /oracle/archive/1_16_799830099.dbf
1 17 22-NOV-12 /oracle/archive/1_17_799830099.dbf
1 18 22-NOV-12 /oracle/archive/1_18_799830099.dbf
1 19 22-NOV-12 /oracle/archive/1_19_799830099.dbf
1 20 22-NOV-12 /oracle/archive/1_20_799830099.dbf
1 21 22-NOV-12 /oracle/archive/1_21_799830099.dbf
1 22 22-NOV-12 /oracle/archive/1_22_799830099.dbf
21 rows selected.
跟踪了rman的recover过程，应用归档以及日志过程如下：
Start recovery at thread 1 ckpt scn 2150426643 logseq 2 block 3763
*** 2012-11-22 14:50:17.753
Media Recovery add redo thread 1
EXEC #3:c=43993,e=1046443,p=8,cr=0,cu=0,mis=0,r=0,dep=0,og=1,tim=1321842790813978
ERROR #3:err=279 tim=436944789
XCTEND rlbk=0, rd_only=1
=====================
PARSING IN CURSOR #2 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842794851740 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #2:c=0,e=767,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842794851734
*** 2012-11-22 14:50:21.928
Media Recovery Log /oracle/archive/1_2_799830099.dbf
=====================
PARSING IN CURSOR #1 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842795236155 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #1:c=0,e=468,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842795236151
*** 2012-11-22 14:50:22.321
Media Recovery Log /oracle/archive/1_3_799830099.dbf
=====================
PARSING IN CURSOR #3 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842795265680 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #3:c=1000,e=525,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842795265675
*** 2012-11-22 14:50:22.352
Media Recovery Log /oracle/archive/1_4_799830099.dbf
=====================
PARSING IN CURSOR #2 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842795285533 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #2:c=0,e=359,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842795285529
*** 2012-11-22 14:50:22.372
Media Recovery Log /oracle/archive/1_5_799830099.dbf
=====================
PARSING IN CURSOR #1 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842795345122 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #1:c=0,e=342,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842795345118
*** 2012-11-22 14:50:22.433
Media Recovery Log /oracle/archive/1_6_799830099.dbf
=====================
PARSING IN CURSOR #3 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842795363994 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #3:c=0,e=391,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842795363990
*** 2012-11-22 14:50:22.452
Media Recovery Log /oracle/archive/1_7_799830099.dbf
=====================
PARSING IN CURSOR #2 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842795384043 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #2:c=0,e=332,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842795384040
*** 2012-11-22 14:50:22.473
Media Recovery Log /oracle/archive/1_8_799830099.dbf
=====================
PARSING IN CURSOR #1 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842804457560 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #1:c=0,e=370,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842804457556
*** 2012-11-22 14:50:31.764
Media Recovery Log /oracle/archive/1_9_799830099.dbf
=====================
PARSING IN CURSOR #3 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842812587561 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #3:c=0,e=507,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842812587556
*** 2012-11-22 14:50:40.089
Media Recovery Log /oracle/archive/1_10_799830099.dbf
=====================
PARSING IN CURSOR #2 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842812693837 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #2:c=1000,e=44536,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842812693833
*** 2012-11-22 14:50:40.198
Media Recovery Log /oracle/archive/1_11_799830099.dbf
=====================
PARSING IN CURSOR #1 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842812721209 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #1:c=0,e=753,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842812721202
*** 2012-11-22 14:50:40.226
Media Recovery Log /oracle/archive/1_12_799830099.dbf
=====================
PARSING IN CURSOR #3 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842812743052 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #3:c=1000,e=526,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842812743048
*** 2012-11-22 14:50:40.249
Media Recovery Log /oracle/archive/1_13_799830099.dbf
=====================
PARSING IN CURSOR #2 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842812816218 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #2:c=0,e=358,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842812816213
*** 2012-11-22 14:50:40.323
Media Recovery Log /oracle/archive/1_14_799830099.dbf
=====================
PARSING IN CURSOR #1 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842814087856 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #1:c=0,e=451,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842814087850
*** 2012-11-22 14:50:41.626
Media Recovery Log /oracle/archive/1_15_799830099.dbf
=====================
PARSING IN CURSOR #3 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842815929158 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #3:c=0,e=446,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842815929153
*** 2012-11-22 14:50:43.511
Media Recovery Log /oracle/archive/1_16_799830099.dbf
=====================
PARSING IN CURSOR #2 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842816552606 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #2:c=0,e=394,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842816552602
*** 2012-11-22 14:50:44.150
Media Recovery Log /oracle/archive/1_17_799830099.dbf
=====================
PARSING IN CURSOR #1 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842816961431 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #1:c=0,e=380,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842816961427
*** 2012-11-22 14:50:44.568
Media Recovery Log /oracle/archive/1_18_799830099.dbf
=====================
PARSING IN CURSOR #3 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842818513605 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #3:c=0,e=356,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842818513601
*** 2012-11-22 14:50:46.158
Media Recovery Log /oracle/archive/1_19_799830099.dbf
=====================
PARSING IN CURSOR #2 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842820154621 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #2:c=0,e=504,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842820154616
*** 2012-11-22 14:50:47.838
Media Recovery Log /oracle/archive/1_20_799830099.dbf
=====================
PARSING IN CURSOR #1 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842822606041 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #1:c=0,e=540,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842822606036
*** 2012-11-22 14:50:50.348
Media Recovery Log /oracle/archive/1_21_799830099.dbf
=====================
PARSING IN CURSOR #3 len=44 dep=0 uid=0 oct=35 lid=0 tim=1321842823929608 hv=2522010750 ad=\'72d39c08\'
ALTER DATABASE RECOVER CONTINUE DEFAULT
END OF STMT
PARSE #3:c=1000,e=842,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,tim=1321842823929598
*** 2012-11-22 14:50:51.704
Media Recovery Log /oracle/archive/1_22_799830099.dbf
*** 2012-11-22 14:50:51.949
Recovery of Online Redo Log: Thread 1 Group 5 Seq 23 Reading mem 0
*** 2012-11-22 14:50:53.872
Recovery of Online Redo Log: Thread 1 Group 6 Seq 24 Reading mem 0
*** 2012-11-22 14:50:56.779
Recovery of Online Redo Log: Thread 1 Group 1 Seq 25 Reading mem 0
*** 2012-11-22 14:50:56.891
Recovery of Online Redo Log: Thread 1 Group 2 Seq 26 Reading mem 0
*** 2012-11-22 14:50:57.413
Recovery of Online Redo Log: Thread 1 Group 3 Seq 27 Reading mem 0
*** 2012-11-22 14:50:58.499
Recovery of Online Redo Log: Thread 1 Group 4 Seq 28 Reading mem 0
很清晰的显示了recover过程，应用归档2-22，联机日志23-28。recover的结尾为当前联机日志的最后一个重做记录。
SQL> select checkpoint_change# from v$datafile_header;
CHECKPOINT_CHANGE#
------------------
2150707413
2150707413
2150707413
2150707413
2150707413
2150707413
2150707413
2150707413
SQL> select checkpoint_change# from v$datafile;
CHECKPOINT_CHANGE#
------------------
2150707413
2150707413
2150707413
2150707413
2150707413
2150707413
2150707413
2150707413
----- Redo read statistics for thread 1 -----
Read rate (ASYNC): 74309Kb in 40.78s => 1.78 Mb/sec
Total physical reads: 77642Kb
Longest record: 23Kb, moves: 0/186197 (0%)
Change moves: 72487/353963 (20%), moved: 33Mb
Longest LWN: 2004Kb, moves: 13/2879 (0%), moved: 6Mb
Last redo scn: 0x0000.803130d4 (2150707412)
总结：
1 restore database后recover 应用归档的结尾：所有联机日志中最小seq号的前一个
2 restore database 后recover应用归档的开始seq号由restore后数据文件头部信息决定
3 restore……preview 虽然对列出恢复所需的文件列表不进行有效性检查，不过我们可以通过命令如 restore validate database|restore validate archivelog sequence between xx and xx 对给出的恢复文件列表进行验证。
本文转自 zhangxuwl 51CTO博客，原文链接：http://blog.51cto.com/jiujian/1073246，如需转载请自行联系原作者
