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。

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;

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