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;
Starting recover at 06-OCT-14
Starting implicit crosscheck backup at 06-OCT-14
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=20 device type=DISK
Crosschecked 6 objects
Finished implicit crosscheck backup at 06-OCT-14
Starting implicit crosscheck copy at 06-OCT-14
using channel ORA_DISK_1
Finished implicit crosscheck copy at 06-OCT-14
searching for all files in the recovery area
cataloging files...
cataloging done
List of Cataloged Files
=======================
File Name: /u01/fast_recovery_area/PRACTICE/archivelog/2014_10_06/o1_mf_1_1_b362kndr_.arc
File Name: /u01/fast_recovery_area/PRACTICE/archivelog/2014_10_06/o1_mf_1_3_b362lc83_.arc
File Name: /u01/fast_recovery_area/PRACTICE/archivelog/2014_10_06/o1_mf_1_2_b362l34q_.arc
File Name: /u01/fast_recovery_area/PRACTICE/autobackup/2014_10_06/o1_mf_s_860251717_b35s05gm_.bkp
File Name: /u01/fast_recovery_area/PRACTICE/autobackup/2014_10_06/o1_mf_s_860251162_b35rgt84_.bkp
File Name: /u01/fast_recovery_area/PRACTICE/autobackup/2014_10_06/o1_mf_s_860251158_b35rgpms_.bkp
File Name: /u01/fast_recovery_area/PRACTICE/autobackup/2014_10_06/o1_mf_s_860246909_b35n9x55_.bkp
using channel ORA_DISK_1
starting media recovery
archived log for thread 1 with sequence 1 is already on disk as file /u01/fast_recovery_area/PRACTICE/archivelog/2014_10_06/o1_mf_1_1_b362kndr_.arc
archived log for thread 1 with sequence 2 is already on disk as file /u01/fast_recovery_area/PRACTICE/archivelog/2014_10_06/o1_mf_1_2_b362l34q_.arc
archived log for thread 1 with sequence 3 is already on disk as file /u01/fast_recovery_area/PRACTICE/archivelog/2014_10_06/o1_mf_1_3_b362lc83_.arc
archived log for thread 1 with sequence 4 is already on disk as file /u01/oradata/practice/redo01.log
archived log file name=/u01/fast_recovery_area/PRACTICE/archivelog/2014_10_06/o1_mf_1_1_b362kndr_.arc thread=1 sequence=1
archived log file name=/u01/fast_recovery_area/PRACTICE/archivelog/2014_10_06/o1_mf_1_2_b362l34q_.arc thread=1 sequence=2
archived log file name=/u01/fast_recovery_area/PRACTICE/archivelog/2014_10_06/o1_mf_1_3_b362lc83_.arc thread=1 sequence=3
archived log file name=/u01/oradata/practice/redo01.log thread=1 sequence=4
media recovery complete, elapsed time: 00:00:00
Finished recover at 06-OCT-14
4，备份控制文件到trace
SYS@practice >select open_mode from v$database;
OPEN_MODE
--------------------
MOUNTED
SYS@practice >alter database backup controlfile to trace;
SYS@practice >select value from v$diag_info where name='Default Trace File';
VALUE
--------------------------------------------------------------------------------
/u01/diag/rdbms/practice/practice/trace/practice_ora_1185.trc
5，重启实例到nomount状态
RMAN> startup force nomount;
Oracle instance started
Total System Global Area 580395008 bytes
Fixed Size 2255392 bytes
Variable Size 402654688 bytes
Database Buffers 171966464 bytes
Redo Buffers 3518464 bytes
6，执行重建控制文件命令进入到mount状态
vi /home/oracle/create_controlfile.sql
STARTUP NOMOUNT
CREATE CONTROLFILE REUSE DATABASE "PRACTICE" NORESETLOGS ARCHIVELOG
MAXLOGFILES 16
MAXLOGMEMBERS 3
MAXDATAFILES 100
MAXINSTANCES 8
MAXLOGHISTORY 292
LOGFILE
GROUP 1 '/u01/oradata/practice/redo01.log' SIZE 50M BLOCKSIZE 512,
GROUP 2 '/u01/oradata/practice/redo02.log' SIZE 50M BLOCKSIZE 512,
GROUP 3 '/u01/oradata/practice/redo03.log' SIZE 50M BLOCKSIZE 512
DATAFILE
'/u01/oradata/practice/system01.dbf',
'/u01/oradata/practice/sysaux01.dbf',
'/u01/oradata/practice/undotbs01.dbf',
'/u01/oradata/practice/users01.dbf',
'/u01/oradata/practice/example01.dbf'
CHARACTER SET AL32UTF8
;
VARIABLE RECNO NUMBER;
EXECUTE :RECNO := SYS.DBMS_BACKUP_RESTORE.SETCONFIG('CONTROLFILE AUTOBACKUP','ON');
RECOVER DATABASE
ALTER SYSTEM ARCHIVE LOG ALL;
ALTER DATABASE OPEN;
ALTER TABLESPACE TEMP ADD TEMPFILE '/u01/oradata/practice/temp01.dbf' REUSE;
在sqlplus下执行创建控制文件脚本，数据库会启动到open状态并添加临时表空间文件。
SYS@practice >@create_controlfile.sql
Control file created.
PL/SQL procedure successfully completed.
Media recovery complete.
System altered.
Database altered.
Tablespace altered.
此时数据库已经处于read write状态也就是open状态了
SYS@practice >select open_mode from v$database;
OPEN_MODE
--------------------
READ WRITE
查看当前日志的序列号，没有被重置。
SYS@practice >select group#,sequence#,archived,status,first_change#,next_change# from v$log;
GROUP# SEQUENCE# ARC STATUS FIRST_CHANGE# NEXT_CHANGE#
---------- ---------- --- ---------------- ------------- ------------
1 4 YES INACTIVE 1030130 1050296
2 5 NO CURRENT 1050296 2.8147E+14
3 3 YES INACTIVE 1030117 1030130
查看临时表数据文件也被创建出来了。
SYS@practice >select name from v$tempfile;
NAME
--------------------------------------------------------------------------------
/u01/oradata/practice/temp01.dbf
7，重新识别控制文件的备份信息和配置信息
此时的控制文件中没有之前备份过控制文件的信息
RMAN> list backup of controlfile;
using target database control file instead of recovery catalog
specification does not match any backup in the repository
从闪回恢复区重新注册备份信息
RMAN> catalog db_recovery_file_dest;
从执行过数据库全备份的地址注册备份信息
RMAN> catalog start with '/home/oracle/';
再次列出备份过的控制文件，可以看到已经全部注册成功
RMAN> list backup of controlfile;
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
1 Full 9.67M DISK 00:00:00 06-OCT-14
BP Key: 1 Status: AVAILABLE Compressed: NO Tag: TAG20141006T175610
Piece Name: /u01/fast_recovery_area/PRACTICE/autobackup/2014_10_06/o1_mf_s_860262970_b363zt2x_.bkp
Control File Included: Ckp SCN: 1051644 Ckp time: 06-OCT-14
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
3 Full 9.33M DISK 00:00:00 06-OCT-14
BP Key: 3 Status: AVAILABLE Compressed: NO Tag: TAG20141006T132827
Piece Name: /u01/fast_recovery_area/PRACTICE/backupset/2014_10_06/o1_mf_ncnnf_TAG20141006T132827_b35n9w39_.bkp
Control File Included: Ckp SCN: 1005439 Ckp time: 06-OCT-14
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
7 Full 9.33M DISK 00:00:00 06-OCT-14
BP Key: 7 Status: AVAILABLE Compressed: NO Tag: TAG20141006T143909
Piece Name: /home/oracle/full_PRACTICE_9_20141006_1.bak
Control File Included: Ckp SCN: 1013438 Ckp time: 06-OCT-14
本次实验到此结束。