对restoredatabasepreview显示结果的思考

一restoredatabasepreview解释：官方说明：YoucanapplyRESTORE...PREVIEWtoanyRESTOREoperationtocreateadetailedlistofeverybackuptobeusedintherequestedRESTO

一 restore database preview 解释：

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:

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 21504263 20-NOV-12 /oracle/CRM2/system1.dbf

2 Full 21504263 20-NOV-12 /oracle/CRM2/zxb.dbf

3 Full 21504263 20-NOV-12 /oracle/CRM2/CRM/sysaux01.dbf

4 Full 21504263 20-NOV-12 /oracle/CRM2/CRM/users01.dbf

5 Full 21504263 20-NOV-12 /oracle/CRM2/zxa.dbf

6 Full 21504263 20-NOV-12 /oracle/CRM2/CRM/test1.dbf

7 Full 21504263 20-NOV-12 /oracle/CRM2/zxc.dbf

8 Full 21504263 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 21504263

Recovery must be done beyond SCN 21504263 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21504263：Media recovery start SCN is 21504263

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: 0x0000.000016 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