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https://issues.apache.org/jira/browse/MAPREDUCE-390?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Allen Wittenauer resolved MAPREDUCE-390.
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Resolution: Fixed
I believe this one has actually been resolved with the rewrite of the pipes
interface.
> Corner case exists in detecting Java process deaths that might lead to orphan
> pipes processes lying around in memory
> --------------------------------------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-390
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-390
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> 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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