恢复控制文件后如何避免resetlogs打开数据库？

恢复控制文件后，数据库使用resetlogs方式打开，在线日志的序列被重置。

恢复控制文件后，数据库使用resetlogs方式打开，在线日志的序列被重置。

SYS@practice >select group#,sequence#,archived,status,first_change#,next_change# from v$log;

GROUP# SEQUENCE# ARC STATUS FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- --- ---------------- ------------- ------------
1 1 NO CURRENT 1014415 2.8147E+14
2 0 YES UNUSED 0 0
3 0 YES UNUSED 0 0

如果没有被resetlog截断的话当前日志的序列号应该是7，8，9
SYS@practice >select recid,sequence#,first_change#,next_change# from v$log_history;

RECID SEQUENCE# FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- ------------- ------------
1 1 925702 955284
2 2 955284 955847
3 3 955847 971151
4 4 971151 987800
5 5 987800 997957
6 6 997957 1010981
7 1 1010981 1013463
8 2 1013463 1013471
9 3 1013471 1014415

如果恢复完控制文件，不使用resetlogs是打不开数据库的。

我们可以采取手工创建控制文件的方法打开数据库，保持联机日志的sequence#连续。下面的实验来演示具体操作过程。

在实验之前先手工切换3次日志，使得在线日志的序列号产生变化。在恢复结束后作为参考。
SYS@practice >alter system archive log current;

SYS@practice >alter system archive log current;

SYS@practice >alter system archive log current;

切换后当前连接日志状态如下
SYS@practice >select group#,sequence#,archived,status,first_change#,next_change# from v$log;

GROUP# SEQUENCE# ARC STATUS FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- --- ---------------- ------------- ------------
1 4 NO CURRENT 1030130 2.8147E+14
2 2 YES INACTIVE 1030109 1030117
3 3 YES ACTIVE 1030117 1030130

1，恢复控制文件
RMAN> startup force nomount;

Oracle instance started

Total System Global Area 580395008 bytes

Fixed Size 2255392 bytes
Variable Size 402654688 bytes
Database Buffers 171966464 bytes
Redo Buffers 3518464 bytes

RMAN> restore controlfile from autobackup;

Starting restore at 06-OCT-14
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=19 device type=DISK

recovery area destination: /u01/fast_recovery_area
database name (or database unique name) used for search: PRACTICE
channel ORA_DISK_1: AUTOBACKUP /u01/fast_recovery_area/PRACTICE/autobackup/2014_10_06/o1_mf_s_860251717_b35s05gm_.bkp found in the recovery area
channel ORA_DISK_1: looking for AUTOBACKUP on day: 20141006
channel ORA_DISK_1: restoring control file from AUTOBACKUP /u01/fast_recovery_area/PRACTICE/autobackup/2014_10_06/o1_mf_s_860251717_b35s05gm_.bkp
channel ORA_DISK_1: control file restore from AUTOBACKUP complete
output file name=/u01/oradata/practice/control01.ctl
output file name=/u01/fast_recovery_area/practice/control02.ctl
Finished restore at 06-OCT-14

2，启动数据库到mount状态
RMAN> mount database;

database mounted
released channel: ORA_DISK_1

3，恢复数据库
RMAN> recover database;