Oracle服务器连接数过多会当掉，把连接数过多的客户机网线拔出后，在远程Oracle上依然还会保留此用户的连接数，久久不能释放，上网查了下可以以下面方法解决。
 
  通过profile可以对用户会话进行一定的限制，比如IDLE时间。
将IDLE超过一定时间的会话断开，可以减少数据库端的会话数量，减少资源耗用。


使用这些资源限制特性，需要设置resource_limit为TRUE：

[oracle@test126 udump]$ sqlplus "/ as sysdba"

SQL*Plus: Release 10.2.0.1.0 - Production on Fri Oct 13 07:58:21 2006

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


Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning and Data Mining options

SQL> show parameter resource

NAME                                TYPE        VALUE
------------------------------------ ----------- ------------------------------
resource_limit                      boolean    TRUE
resource_manager_plan                string


该参数可以动态修改：

SQL> alter system set resource_limit=true;

System altered.


数据库缺省的PROFILE设置为：

SQL> SELECT * FROM DBA_PROFILES;

PROFILE              RESOURCE_NAME                    RESOURCE LIMIT
-------------------- -------------------------------- -------- ---------------
DEFAULT              COMPOSITE_LIMIT                  KERNEL  UNLIMITED
DEFAULT              SESSIONS_PER_USER                KERNEL  UNLIMITED
DEFAULT              CPU_PER_SESSION                  KERNEL  UNLIMITED
DEFAULT              CPU_PER_CALL                    KERNEL  UNLIMITED
DEFAULT              LOGICAL_READS_PER_SESSION        KERNEL  UNLIMITED
DEFAULT              LOGICAL_READS_PER_CALL          KERNEL  UNLIMITED
DEFAULT              IDLE_TIME                        KERNEL  UNLIMITED
DEFAULT              CONNECT_TIME                    KERNEL  UNLIMITED
DEFAULT              PRIVATE_SGA                      KERNEL  UNLIMITED
DEFAULT              FAILED_LOGIN_ATTEMPTS            PASSWORD 10
DEFAULT              PASSWORD_LIFE_TIME              PASSWORD UNLIMITED

PROFILE              RESOURCE_NAME                    RESOURCE LIMIT
-------------------- -------------------------------- -------- ---------------
DEFAULT              PASSWORD_REUSE_TIME              PASSWORD UNLIMITED
DEFAULT              PASSWORD_REUSE_MAX              PASSWORD UNLIMITED
DEFAULT              PASSWORD_VERIFY_FUNCTION        PASSWORD NULL
DEFAULT              PASSWORD_LOCK_TIME              PASSWORD UNLIMITED
DEFAULT              PASSWORD_GRACE_TIME              PASSWORD UNLIMITED

16 rows selected.


创建一个允许3分钟IDLE时间的PROFILE：

SQL> CREATE PROFILE KILLIDLE LIMIT IDLE_TIME 3;

Profile created.


新创建PROFILE的内容：

SQL> col limit for a10
SQL> select * from dba_profiles where profile='KILLIDLE';

PROFILE                        RESOURCE_NAME                    RESOURCE LIMIT
------------------------------ -------------------------------- -------- ----------
KILLIDLE                      COMPOSITE_LIMIT                  KERNEL  DEFAULT
KILLIDLE                      SESSIONS_PER_USER                KERNEL  DEFAULT
KILLIDLE                      CPU_PER_SESSION                  KERNEL  DEFAULT
KILLIDLE                      CPU_PER_CALL                    KERNEL  DEFAULT
KILLIDLE                      LOGICAL_READS_PER_SESSION        KERNEL  DEFAULT
KILLIDLE                      LOGICAL_READS_PER_CALL          KERNEL  DEFAULT
KILLIDLE                      IDLE_TIME                        KERNEL  3
KILLIDLE                      CONNECT_TIME                    KERNEL  DEFAULT
KILLIDLE                      PRIVATE_SGA                      KERNEL  DEFAULT
KILLIDLE                      FAILED_LOGIN_ATTEMPTS            PASSWORD DEFAULT
KILLIDLE                      PASSWORD_LIFE_TIME              PASSWORD DEFAULT

PROFILE                        RESOURCE_NAME                    RESOURCE LIMIT
------------------------------ -------------------------------- -------- ----------
KILLIDLE                      PASSWORD_REUSE_TIME              PASSWORD DEFAULT
KILLIDLE                      PASSWORD_REUSE_MAX              PASSWORD DEFAULT
KILLIDLE                      PASSWORD_V