汇总整理一下有关重做日志文件（redo log files）管理相关的操作（增，删，改，查，切）。供参考。
1.当前日志相关信息
sys@ora11g> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- --------- ------------- ---------
1 1 10 209715200 1 YES INACTIVE 461938 09-MAR-09
2 1 11 209715200 1 NO CURRENT 485885 09-MAR-09
3 1 9 209715200 1 YES INACTIVE 432636 04-MAR-09
sys@ora11g> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- -------------------- ---------------------------------------- ---
1 ONLINE /oracle/u02/oradata/ora11g/redo01.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03.log NO
2.添加重做日志组
sys@ora11g>alter database add logfile group 4 ('/oracle/u02/oradata/ora11g/redo04_01.log','/oracle/u02/oradata/ora11g/redo04_02.log') size 50m;
Database altered.
sys@ora11g> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- --------- ------------- ---------
1 1 10 209715200 1 YES INACTIVE 461938 09-MAR-09
2 1 11 209715200 1 NO CURRENT 485885 09-MAR-09
3 1 9 209715200 1 YES INACTIVE 432636 04-MAR-09
4 1 0 52428800 2 YES UNUSED 0
sys@ora11g> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- -------------------- ---------------------------------------- ---
1 ONLINE /oracle/u02/oradata/ora11g/redo01.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03.log NO
4 ONLINE /oracle/u02/oradata/ora11g/redo04_01.log NO
4 ONLINE /oracle/u02/oradata/ora11g/redo04_02.log NO
3.添加日志文件
sys@ora11g>alter database add logfile member
'/oracle/u02/oradata/ora11g/redo01_02.log' to group 1,
'/oracle/u02/oradata/ora11g/redo02_02.log' to group 2,
'/oracle/u02/oradata/ora11g/redo03_02.log' to group 3;
Database altered.
sys@ora11g> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- --------- ------------- ---------
1 1 10 209715200 2 YES INACTIVE 461938 09-MAR-09
2 1 11 209715200 2 NO CURRENT 485885 09-MAR-09
3 1 9 209715200 2 YES INACTIVE 432636 04-MAR-09
4 1 0 52428800 2 YES UNUSED 0
sys@ora11g> select * from v$logfile order by 1;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- -------------------- ---------------------------------------- ---
1 ONLINE /oracle/u02/oradata/ora11g/redo01.log NO
1 INVALID ONLINE /oracle/u02/oradata/ora11g/redo01_02.log NO
2 INVALID ONLINE /oracle/u02/oradata/ora11g/redo02_02.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03.log NO
3 INVALID ONLINE /oracle/u02/oradata/ora11g/redo03_02.log NO
4 ONLINE /oracle/u02/oradata/ora11g/redo04_02.log NO
4 ONLINE /oracle/u02/oradata/ora11g/redo04_01.log NO
8 rows selected.
4.重命名日志成员
在重命名日志组成员之前新的目标必须已经存在。Oracle的sql命令只是把控制文件中的内部指针指向新的日志文件。
1）关闭数据库
sys@ora11g> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
2）使用操作系统命令重命名或移动日志文件
ora11g@RHEL53 /oracle/u02/oradata/ora11g$mv redo01.log redo01_01.log
ora11g@RHEL53 /oracle/u02/oradata/ora11g$mv redo02.log redo02_01.log
ora11g@RHEL53 /oracle/u02/oradata/ora11g$mv redo03.log redo03_01.log
3）启动数据库实例到mount状态，重命名控制文件中的日志文件成员。
NotConnected@> select * from v$logfile order by 1,4;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- -------------------- ------------------------------------------ ---
1 ONLINE /oracle/u02/oradata/ora11g/redo01.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03.log NO
4 ONLINE /oracle/u02/oradata/ora11g/redo04_01.log NO
4 ONLINE /oracle/u02/oradata/ora11g/redo04_02.log NO
1 ONLINE /oracle/u02/oradata/ora11g/redo01_02.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02_02.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03_02.log NO
8 rows selected.
NotConnected@>alter database rename file '/oracle/u02/oradata/ora11g/redo01.log' to '/oracle/u02/oradata/ora11g/redo01_01.log';
Database altered.
NotConnected@>alter database rename file '/oracle/u02/oradata/ora11g/redo02.log' to '/oracle/u02/oradata/ora11g/redo02_01.log';
Database altered.
NotConnected@>alter database rename file '/oracle/u02/oradata/ora11g/redo03.log' to '/oracle/u02/oradata/ora11g/redo03_01.log';
Database altered.
4）open数据库，验证结果
NotConnected@>alter database open;
Database altered.
sys@ora11g> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- -------- ------------- ---------
1 1 18 209715200 2 YES INACTIVE 486960 09-MAR-09
2 1 19 209715200 2 YES INACTIVE 486964 09-MAR-09
3 1 21 209715200 2 NO CURRENT 486973 09-MAR-09
4 1 20 52428800 2 YES INACTIVE 486968 09-MAR-09
sys@ora11g> select * from v$logfile order by 1,4;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- -------------------- ------------------------------------------ ---
1 ONLINE /oracle/u02/oradata/ora11g/redo01_01.log NO
1 ONLINE /oracle/u02/oradata/ora11g/redo01_02.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02_01.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02_02.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03_01.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03_02.log NO
4 ONLINE /oracle/u02/oradata/ora11g/redo04_01.log NO
4 ONLINE /oracle/u02/oradata/ora11g/redo04_02.log NO
8 rows selected.
5）最后，不要忘记备份控制文件
sys@ora11g>alter database backup controlfile to trace;
Database altered.
5.删除一个非活动的重做日志组的成员
sys@ora11g> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- -------- ------------- ---------
1 1 18 209715200 2 YES INACTIVE 486960 09-MAR-09
2 1 19 209715200 2 YES INACTIVE 486964 09-MAR-09
3 1 21 209715200 2 NO CURRENT 486973 09-MAR-09
4 1 20 52428800 2 YES INACTIVE 486968 09-MAR-09
sys@ora11g>alter database drop logfile member '/oracle/u02/oradata/ora11g/redo04_02.log';
Database altered.
sys@ora11g> !ls -l /oracle/u02/oradata/ora11g/redo04_02.log
-rw-r----- 1 oracle oinstall 52429312 Mar 9 16:28 /oracle/u02/oradata/ora11g/redo04_02.log
sys@ora11g>!rm -f /oracle/u02/oradata/ora11g/redo04_02.log
sys@ora11g> select * from v$logfile order by 1,4;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- -------------------- ------------------------------------------ ---
1 ONLINE /oracle/u02/oradata/ora11g/redo01_01.log NO
1 ONLINE /oracle/u02/oradata/ora11g/redo01_02.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02_01.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02_02.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03_01.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03_02.log NO
4 ONLINE /oracle/u02/oradata/ora11g/redo04_01.log NO
7 rows selected.
6.删除一个非活动的重做日志组
sys@ora11g>alter database drop logfile group 4;
Database altered.
sys@ora11g>!rm -f /oracle/u02/oradata/ora11g/redo04_01.log
sys@ora11g> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- -------------------- ------------------------------------------ ---
1 ONLINE /oracle/u02/oradata/ora11g/redo01_01.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02_01.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03_01.log NO
1 ONLINE /oracle/u02/oradata/ora11g/redo01_02.log NO
2 ONLINE /oracle/u02/oradata/ora11g/redo02_02.log NO
3 ONLINE /oracle/u02/oradata/ora11g/redo03_02.log NO
6 rows selected.
7.强制切换日志
sys@ora11g>alter system switch logfile;
System altered.
sys@ora11g>alter system archive log current;
System altered.
8.小结
1）日志文件非常重要，当多路复用重做日志文件时，应该把一个组的成员保存在不同的磁盘上。
2）在完成日志文件维护后一定要记得备份最新的控制文件！
3）以上试验是在11g环境下完成的，在10g环境中一样适用。
Good luck.
secooler
09.03.09
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