[jira] [Commented] (HADOOP-10597) Evaluate if we can have RPC client back off when server is under heavy load

["Steve Loughran (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-10597?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13998689#comment-13998689 ] 

Steve Loughran commented on HADOOP-10597:
-----------------------------------------

this could be useful for clients of other services too, where the back-off message could trigger redirect.

maybe the response could include some hints of 
# where else to go
# backoff parameter hints: sleep time, growth, jitter. This gives the NN more control of the clients, lets you spread the jitter, and grow the backoff time as load increases -so reducing socket connection load.

> 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
>
> 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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