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From "Doug Cutting (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-491) streaming jobs should allow programs that don't do any IO for a long time
Date Mon, 05 Feb 2007 20:09:05 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-491?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12470338
] 

Doug Cutting commented on HADOOP-491:
-------------------------------------

So streaming jobs should have no timeout by default?  I can sort of see adding the feature
of disabling task timeouts, and also of facillitating this from streaming, but do streaming
applications really never hang?  Should we change the default for all applications, not just
streaming?  I'm trying to understand the logic here.

Also, as a new feature, shouldn't this be targetted for 0.12.0?


> streaming jobs should allow programs that don't do any IO for a long time
> -------------------------------------------------------------------------
>
>                 Key: HADOOP-491
>                 URL: https://issues.apache.org/jira/browse/HADOOP-491
>             Project: Hadoop
>          Issue Type: New Feature
>          Components: contrib/streaming
>    Affects Versions: 0.11.0
>            Reporter: arkady borkovsky
>         Assigned To: Arun C Murthy
>             Fix For: 0.11.1
>
>         Attachments: HADOOP-491_20070205_1.patch
>
>
> The jobtracker relies on task to send heartbeats  to know the tasks are still alive.
> There is a 600 seconds timeout preset.
> hadoop streaming also uses input to or output from the program it spawns to indicate
progress, sending appropriate heartbeats.
> Some spawned programs spend longer that 600 seconds without any output while being perfectly
healthy.
> It would be good to enhance the interface between hadoop streaming and the programs it
spawns to track a healthy program in the absense of output.
> There are certain dangers with this protocol: e.g. a task can run a separate thread that
does nothing but send "i'm alive" message.   This would be a user bug to abuse the API in
such way.  

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