一套10.2.0.5 的数据库，告警日志中反复出现"Restarting dead background process QMNC"的信息，具体日志如下：
Thu Jun 07 10:38:28 GMT 2012 Restarting dead background process QMNC QMNC started with pid=271, OS id=17059 Thu Jun 07 10:43:08 GMT 2012 Restarting dead background process QMNC QMNC started with pid=234, OS id=18263但是通过ps 命令查看 重启的QMNC进程很快又消失掉， Metalink Note Restarting dead background process QMNC recorded in the alert.log file [ID 395137.1]说明了该问题
Applies to: Oracle Server - Enterprise Edition - Version: 10.1.0.2 to 11.2.0.2 - Release: 10.1 to 11.2 Information in this document applies to any platform. Checked for currency 06-Sep-10 Symptoms The following messages are recorded in the alert log every 5 minutes Restarting dead background process QMNC Changes Cause 1. database startup : The database has not opened for an undetermined reason, i.e there is no statement: Completed: ALTER DATABASE OPEN recorded in the alert.log file. 2. database shutdown : A process may be preventing the database from shutting down cleanly. As a consequence, this may be causing the qmnc process problems. Solution This is expected behaviour. The reason why the database has not opened or shutdown should be investigated. These messages are a symptom of the problem and not the underlying cause.
该问题除了会在 alert.log中每五分钟生成一次 "Restarting dead background process QMNC"的信息外，不会造成其他影响，一般可以忽略。 该警告信息可能由于ORACLE INSTANCE未能正常关闭引起(即shutdown不是clean干净的)， 查询之前的alert.log 发现有一个EMN0进程在上一次shutdown immediate时被启动，且一直存在着： Starting background process EMN0 Wed Jun 06 19:30:26 GMT 2012 Shutting down instance: further logons disabled EMN0 started with pid=47, OS id=322 EMN0是一个高级队列advanced Queuing相关的进程，该进程不是关键后台进程 ， 必须时可以被 KILL掉 The EMNO process is new to Oracle8i, and has to do with improvements made to Advanced Queuing, specifically: A combination of features are introduced to allow a publish/subscribe style of
本文转自maclean_007 51CTO博客，原文链接:http://blog.51cto.com/maclean/1277757
