在之前的文章中有三篇提到了oracle的监听，如下：
oracle listener 动态注册 与 静态注册
oracle 监听(listener) 中 services 说明
oracle 数据库监听配置
oracle的监听(listener)在缺省情况下，会在文件中记录日志，记录数据库实例注册操作、客户端的连接等。
oracle 11g中的信息如下：
[oracle@dave ~]$ lsnrctl status
lsnrctl for linux: version 11.2.0.3.0 - productionon 22-dec-2012 21:36:43
copyright (c) 1991, 2011, oracle. all rights reserved.
connecting to(description=(address=(protocol=tcp)(host=192.168.1.4)(port=1521)))
status of the listener
------------------------
alias listener
version tnslsnr for linux: version11.2.0.3.0 - production
start date 22-dec-2012 21:31:53
uptime 0 days 0 hr. 4 min. 50 sec
trace level off
security on: local os authentication
snmp off
listener parameter file /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
listener log file /u01/app/oracle/diag/tnslsnr/dave/listener/alert/log.xml
listening endpoints summary...
(description=(address=(protocol=tcp)(host=192.168.1.4)(port=1521)))
services summary...
service dave has 2 instance(s).
instance dave, status unknown, has 1 handler(s) for thisservice...
instance dave, status ready, has 1 handler(s) for thisservice...
service davexdb has 1instance(s).
instance dave, status ready, has 1 handler(s) for thisservice...
the command completed successfully
，