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https://issues.apache.org/jira/browse/HADOOP-1651?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12515943
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Arun C Murthy commented on HADOOP-1651:
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I don't think we need to log the 'Ping thread started' at *info*, no?
Else, +1 for the patch.
Somewhat related gripe: I'd think it might be useful to stop the {{Task}} ->
{{TaskTracker}} communication thread on Task completion i.e. at {{Task.done}}
... what do others think? I'm ok with this being done as a part of a separate
issue of course.
> Some improvements in progress reporting
> ---------------------------------------
>
> Key: HADOOP-1651
> URL: https://issues.apache.org/jira/browse/HADOOP-1651
> Project: Hadoop
> Issue Type: Bug
> Components: mapred
> Reporter: Devaraj Das
> Assignee: Devaraj Das
> Fix For: 0.15.0
>
> Attachments: 1651.1.patch, 1651.2.patch, 1651.patch
>
>
> Some improvements that can be done:
> 1) Progress reporting interval can be made slightly large. It is currently 1
> second. Propose to make it 3 seconds to reduce the load on the TaskTracker.
> 2) Progress reports can potentially be missed. In the loop, if the first
> attempt at reporting a progress doesn't go through, it is not retried. The
> next communication will be a 'ping'.
> 3) If there is an exception while reporting progress or doing ping, the
> client should sleep for sometime before retrying.
> 4) The TaskUmbilicalProtocol client can always stay connected to the server.
> Currently, the default idle timeout on the IPC client is set to 1000 msec
> (this means that the client will disconnect if the connection has been idle
> for 1000 msec). This might lead to unnecessary tearing-down/setting-up of
> connections for the TaskUmbilicalProtocol and can be avoided by having a high
> idle timeout for this protocol. The idea behind having the idle timeout was
> to not hold on to server connections unnecessarily and hence be more scalable
> when there are 1000s of clients, especially applicable to those protocols
> involving the JT and the NameNode. We don't run into scalability issues with
> TaskUmbilical protocol since it is limited to a few Tasks and the
> corresponding TaskTracker.
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