1、查看当前的日志文件信息
SQL> select group#,status from v$log ;
GROUP# STATUS
---------- ------------------------------------------------
1 CURRENT
2 INACTIVE
SQL> select member from v$logfile;
MEMBER
--------------------------------------------------------------------------------
/oracle/oradata/test/redo02.log
/oracle/oradata/test/redo01.log
SQL> select bytes from v$log;
BYTES
----------
52428800
52428800
2、增加2个redo日志组
SQL> alter database add logfile thread 1 group 4 ('/oracle/oradata/test/redo04.log') size 30M;
alter database add logfile thread 1 group 5 ('/oracle/oradata/test/redo05.log') size 30M;
Database altered.
SQL>
Database altered.
SQL> select member from v$logfile;
MEMBER
--------------------------------------------------------------------------------
/oracle/oradata/test/redo04.log
/oracle/oradata/test/redo02.log
/oracle/oradata/test/redo01.log
/oracle/oradata/test/redo05.log
SQL> select group#,status from v$log;
GROUP# STATUS
---------- ------------------------------------------------
1 CURRENT
2 INACTIVE
4 UNUSED
5 UNUSED
3、进行日志切换，切换到新的组上。
SQL> alter system switch logfile;
System altered.
SQL> select group#,status from v$log;
GROUP# STATUS
---------- ------------------------------------------------
1 ACTIVE
2 INACTIVE
4 CURRENT ---》当前的日志组
5 UNUSED
SQL> select group#,status from v$log;
GROUP# STATUS
---------- ------------------------------------------------
1 ACTIVE
2 INACTIVE
4 CURRENT
5 UNUSED
由于日志切换的增量检查点ACTIVE状态有可能会很久才会变更为INACTIVE，需要发布全量检查点。
SQL> alter system checkpoint;
System altered.
SQL> select group#,status from v$log;
GROUP# STATUS
---------- ------------------------------------------------
1 INACTIVE
2 INACTIVE
4 INACTIVE
5 CURRENT
4、删除group 1、group 2
SQL> alter database drop logfile group 1;
Database altered.
SQL> alter database drop logfile group 2;
Database altered.
SQL> select group#,status from v$log;
GROUP# STATUS
---------- ------------------------------------------------
4 INACTIVE
5 CURRENT
SQL> alter system switch logfile;
System altered.
SQL> /