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https://issues.apache.org/jira/browse/HADOOP-2719?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Robert Chansler updated HADOOP-2719:
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    Fix Version/s:     (was: 0.17.0)

> Corner case exists in detecting Java process deaths that might lead to orphan 
> pipes processes lying around in memory
> --------------------------------------------------------------------------------------------------------------------
>
>                 Key: HADOOP-2719
>                 URL: https://issues.apache.org/jira/browse/HADOOP-2719
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: pipes
>    Affects Versions: 0.16.0
>            Reporter: Devaraj Das
>            Priority: Minor
>
> In HADOOP-2092, the child pipes process periodically pings the parent Java 
> process to find out whether it is alive. The ping cycle is 5 seconds. 
> Consider the following scenario:
> 1) The Java task dies at the beginning of the ping cycle
> 2) A new Java task starts and binds to the same port as the earlier Java 
> task's port
> 3) The pipes process wakes up and does a ping - it will still be successful 
> since the port number hasn't changed
> This will lead to orphan processes lying around in memory. The detection of 
> parent process deaths can be made more reliable at least on Unix'ish 
> platforms by checking whether the parent process ID is 1, and if so exit. 
> This will take care of the most common platform that hadoop is run on. For 
> non-unix platforms, the existing ping mechanism can be retained. Thoughts?

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