在将备用数据库从只读模式转换到管理恢复模式时，出现如下错误
[oracle@casdbbak ~]$ sqlplus /nolog
SQL*Plus: Release 9.2.0.4.0 - Production on Thu May 10 18:03:57 2007
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
SQL> conn / as sysdba;
Connected.
SQL> alter database recover managed standby database disconnect from session;
alter database recover managed standby database disconnect from session
*
ERROR at line 1:
ORA-01093: ALTER DATABASE CLOSE only permitted with no sessions connected
通过检查oracle alert文件，发现Active process 20009正在连接到备用数据库上，验证方式如下
Thu May 10 18:04:08 2007
alter database recover managed standby database disconnect from session
Thu May 10 18:04:08 2007
Active process 20009 user 'oracle' program 'oracle@casdbbak (TNS V1-V3)'
CLOSE: 1 or more sessions failed to shutdown.
Active process 20009 user 'oracle' program 'oracle@casdbbak (TNS V1-V3)'
CLOSE: Active sessions prevent database close operation
CLOSE: Error 1093 during database close
ORA-1093 signalled during: alter database recover managed standby database d...
SQL> host
[oracle@casdbbak ~]$ ps -ef
oracle 20009 20006 0 16:55 ? 00:00:00 oraclegdcas (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))
