[jira] [Comment Edited] (HADOOP-12421) Add jitter to RetryInvocationHandler

["Jing Zhao (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-12421?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15224972#comment-15224972 ] 

Jing Zhao edited comment on HADOOP-12421 at 4/4/16 8:21 PM:
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Thanks for working on this, [~eclark]. One quick question is currently the client's retry policy in HA setup, {{FailoverOnNetworkExceptionRetry}}, already includes randomness in {{calculateExponentialTime}}. Do you know why this cannot avoid the spike and why an extra jitter can help here?


was (Author: jingzhao):
Thanks for working on this, [~eclark]. One quick question is currently the client's retry policy, {{FailoverOnNetworkExceptionRetry}}, already includes randomness in {{calculateExponentialTime}}. Do you know why this cannot avoid the spike and why an extra jitter can help here?

> Add jitter to RetryInvocationHandler
> ------------------------------------
>
>                 Key: HADOOP-12421
>                 URL: https://issues.apache.org/jira/browse/HADOOP-12421
>             Project: Hadoop Common
>          Issue Type: Bug
>    Affects Versions: 2.8.0
>            Reporter: Elliott Clark
>            Assignee: Elliott Clark
>         Attachments: HADOOP-12421-v1.patch, HADOOP-12421-v2.patch, HADOOP-12421-v3.patch, HADOOP-12421-v4.patch, HADOOP-12421-v5.patch
>
>
> Calls to NN can become synchronized across a cluster during NN failover. This leads to a spike in requests until things recover. Making an already tricky time worse.



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