一、redo日志文件

1、查看redo日志文件

select * from v$logfile;

    GROUP# STATUS  TYPE    MEMBER                         IS_
---------- ------- ------- ------------------------------ ---
         1         ONLINE  /u01/app/oracle/oradata/test/r NO
                           edo01a.log

         2         ONLINE  /u01/app/oracle/oradata/test/r NO
                           edo02a.log

2、查看redo 日志文件状态

select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
         2          1         66   10485760          1 YES ACTIVE                  248183 04-JAN-12
         1          1         67   10485760          1 NO  CURRENT                 248204 04-JAN-12

3、切换redo日志文件

SQL> alter system switch logfile;

System altered.

SQL>  select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
         2          1         68   10485760          1 NO  CURRENT                 248392 04-JAN-12
         1          1         67   10485760          1 YES ACTIVE                  248204 04-JAN-12

4、增加redo日志文件

SQL> alter database add logfile group 3('/u01/app/oracle/oradata/test/redo03a.log') size 11m;

Database altered.

SQL> select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
         1          1         69   10485760          1 YES INACTIVE                251660 04-JAN-12
         3          1          0   11534336          1 YES UNUSED                       0
         2          1         70   10485760          1 NO  CURRENT                 252086 04-JAN-12

5、多元化redo日志文件

SQL> alter database add logfile group 6 ('/u01/app/oracle/oradata/test/redo06a.log','/u01/app/oracle/oradata/test/redo06b.log') size 11m;

Database altered.

SQL> select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
         1          1         84   10485760          1 NO  CURRENT                 252959 04-JAN-12
         2          1         82   10485760          1 YES INACTIVE                252955 04-JAN-12
         6          1          0   11534336          2 YES UNUSED                       0
         3          1         83   11534336          1 YES INACTIVE                252957 04-JAN-12
         5          2          0   11534336          2 YES UNUSED                       0
         4          2          0   11534336          1 YES UNUSED                       0