Linux下Oracle下監聽服務動不動停止Listener.ora ：WARNING: Subscription for node down event still pending

今天做實驗，發現listener.ora文件裏有這個報錯：WARNING: Subscription for node down event still pending。

 網上查了一下，大概有如下幾種說法：

Issue is fixed in 10.2.0.3 Patch Set
Oracle Support recommends patching to 10.2.0.4 as this the lastest release

- OR -

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

- OR -

As a workaround, two steps should be done:

1. 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. This parameter is to be placed by itself on an empty line / at the end of file.

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

SUBSCRIBE_FOR_NODE_DOWN_EVENT_LISTENER=OFF

2. Locate the ons.config file in the 10g(rdbms) home and rename it to something else.
For example:

cd $ORACLE_HOME/opmn/conf
mv ons.config ons.config.orig

The listener needs to be restarted after these changes.

--end--

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檢查時會發現系統上存在兩個監聽器進程，其中一個是另外一個的子進程。

檢查監聽 ps -ef | grep tnslsnr

KILL掉一個子進程，恢復正常

在Metalink上可以找到相關問題的很多解釋，這個問題被最終確認爲一個BUG，BUG號爲：4518443
Oracle稱在較大壓力下，監聽進程可能出現間歇性停止服務，此時Oracle會spaw出另外一個監聽進程，進而導致兩個監聽進程互相影響的故障。