Intermittent TNS listener hang, new child listener process forked

주로 10g에서 발생한다고 하는데..아무 로그도 없고 , 이유없이 listener 가 Hang 이 걸릴때 조치방법입니다. listener 를 하나 띄워도 OS에서 계속 spawn 시켜서 listener가 4개가 생성되는 증상이 있을때 해보면 됨.
 
10.2.0.3 에서 fix 되었다고 나와있네요.

==================================================================================


Oracle Net Services - Version: 10.1.0.2.0 to 10.2.0.3.0
This problem can occur on any platform.
All new connections via TNS listener hang, no errors reported

Symptoms

Intermittently the TNS listener hangs and new connections to the database are not possible.

Listener process can also consume high amount of CPU

Child TNS listener process is seen when doing a ps on the listener process, eg.:

$ ps -ef | grep tnslsnr

ora10g  8909     1  0   Sep 15 ?       902:44  /u05/10GHOME/DBHOME/bin/tnslsnr sales -inherit
ora10g 22685  8909  0 14:19:23 ?        0:00 /u05/10GHOME/DBHOME/bin/tnslsnr sales –inherit


Killing the child process allows new connections to work until the problem reoccurs

Cause

This is a known problem addressed via non-published bug:4518443 (Abstract: Listener Gets Hung Up)

The issue is that the TNS listener can hang under load while spawning a process

Solution

Bug 4518443 is fixed in 10.2.0.3

 - OR -

Apply Patch 4518443  for the problem (if a patch is available)

 - OR -

As a workaround, the following parameter can be added to listener.ora

SUBSCRIBE_FOR_NODE_DOWN_EVENT_<listener_name>=OFF

Where <listener_name> should be replaced with the actual listener name configured in the LISTENER.ORA file.

For example, if the listener name is LISTENER (default), the parameter would be:

SUBSCRIBE_FOR_NODE_DOWN_EVENT_LISTENER=OFF

This will prevent the listener from registering against ONS (Oracle Notification Services), which is the area affected by bug:4518443. For more information on ONS, please refer to eg. the Oracle10g Release 2 documentation ("Oracle Clusterware and Oracle Real Application Clusters Administration and Deployment Guide").

Please note, adding SUBSCRIBE_FOR_NODE_DOWN_EVENT_<listener_name> to listener.ora file on RAC, will mean that FAN (fast application notification) will not be possible. See Note 220970.1 RAC: Frequently Asked Questions for further information on FAN