一个网友在论坛发现这样一种奇怪情况：

SQL> startup mount;
ORACLE instance started.

Total System Global Area 1241513984 bytes
Fixed Size                  1219136 bytes
Variable Size             402654656 bytes
Database Buffers          822083584 bytes
Redo Buffers               15556608 bytes
Database mounted.
SQL> alter database noarchivelog;

Database altered.

SQL> alter database open;

Database altered.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup;
ORACLE instance started.

Total System Global Area 1241513984 bytes
Fixed Size                  1219136 bytes
Variable Size             402654656 bytes
Database Buffers          822083584 bytes
Redo Buffers               15556608 bytes
Database mounted.
Database opened.
SQL> archive log list;
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     69
Current log sequence           71
SQL> select count(*) from test;
select count(*) from test
                     *
ERROR at line 1:
ORA-00942: table or view does not exist


SQL> archive log list;
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     69
Current log sequence           71
SQL> alter system switch logfile;

System altered.

SQL> archive log list;
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     70
Current log sequence           72
SQL> archive log list;
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     70
Current log sequence           72
SQL> shutdown immeidate;
SP2-0717: illegal SHUTDOWN option
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area 1241513984 bytes
Fixed Size                  1219136 bytes
Variable Size             402654656 bytes
Database Buffers          822083584 bytes
Redo Buffers               15556608 bytes
Database mounted.
SQL> archive log list;
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     70
Current log sequence           72

-------在这之前都没问题， 然后我在其它的窗口， 用rman 连接了一下， 结果就出现了下面的情况了：

[oracle@myxinnet-2 oracle]$ rman1 target /

Recovery Manager: Release 10.2.0.1.0 - Production on Fri Jun 27 14:42:05 2008

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

connected to target database: HUNTER (DBID=207206589)


SQL> archive log list;
ORA-01155: the database is being opened, closed, mounted or dismounted
SQL> archive log list;
ORA-01155: the database is being opened, closed, mounted or dismounted
SQL> conn / as sysdba
Connected.
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     73
Next log sequence to archive   75
Current log sequence           75
SQL>
解决办法：

data gurad broker 问题，  这个系统在之前有人配置过data gurad broker
用dgmgrl > remover configuration 后 现在正常了。

错误原因：

SQL> archive log list;
ORA-01155: the database is being opened, closed, mounted or dismounted
SQL> archive log list;
ORA-01155: the database is being opened, closed, mounted or dismounted