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https://issues.apache.org/jira/browse/HADOOP-10597?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14077154#comment-14077154
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Jing Zhao commented on HADOOP-10597:
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This can be a very useful feature. For the evaluation, maybe It will be helpful
to see how the change will affect the request latency and NN throughput when
the workload of NN increases from low to high. For example, one of my questions
is that when the NN workload is just relatively high (there are some but not
many requests are blocking on the queue), will the average latency and
throughput be affected if NN directly lets client back off instead of blocking
and timeout?
> Evaluate if we can have RPC client back off when server is under heavy load
> ---------------------------------------------------------------------------
>
> Key: HADOOP-10597
> URL: https://issues.apache.org/jira/browse/HADOOP-10597
> Project: Hadoop Common
> Issue Type: Sub-task
> Reporter: Ming Ma
> Assignee: Ming Ma
> Attachments: HADOOP-10597-2.patch, HADOOP-10597.patch,
> RPCClientBackoffDesignAndEvaluation.pdf
>
>
> Currently if an application hits NN too hard, RPC requests be in blocking
> state, assuming OS connection doesn't run out. Alternatively RPC or NN can
> throw some well defined exception back to the client based on certain
> policies when it is under heavy load; client will understand such exception
> and do exponential back off, as another implementation of
> RetryInvocationHandler.
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