Oracle数据库改变redo日志大小

1、查看当前redo日志状态

SQL> select group#, bytes, status from v$log;

    GROUP#      BYTES STATUS

---------- ---------- ----------------

         1  209715200 INACTIVE

         2  209715200 CURRENT

         3  209715200 UNUSED

 SQL> select group#, member from v$logfile;

    GROUP#      ----------    MEMBER

--------------------------------------------------------------------------------

         3             /data/orcl/redo03.log

         2             /data/orcl/redo02.log

         1             /data/orcl/redo01.log

目前，单个redo日志大小为200M

2、改变日志大小

2.1、不能删除 current状态下日志组

SQL> alter database drop logfile group 2;

alter database drop logfile group 2

*

ERROR at line 1:

ORA-01623: log 2 is current log for instance orcl (thread 1) - cannot drop

ORA-00312: online log 2 thread 1: '/data/orcl/redo02.log'

可手动切换redo日志，改变当前日志组。

2.2、不能删除active状态下日志组

手动执行检查点，因active状态日志为检查点尚未完成的状态。

2.3、添加删除日志组1，改变大小

SQL> alter database drop logfile group 1;

Database altered.

手动删除物理文件后，添加日志组1

SQL> alter database add logfile group 1 '/data/orcl/redo01.log' size 300M;

Database altered.

依次删除日志组，添加日志组；切换redo日志，改变所有组redo大小。

3、验证

 SQL> select group#, bytes, status from v$log;

    GROUP#      BYTES STATUS

---------- ---------- ----------------

         1  314572800 CURRENT

         2  314572800 UNUSED

         3  314572800 UNUSED

 

SQL> select group#, member from v$logfile;

  GROUP#    ----------    MEMBER

--------------------------------------------------------------------------------

         3            /data/orcl/redo03.log

         2            /data/orcl/redo02.log

         1            /data/orcl/redo01.log