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https://issues.apache.org/jira/browse/HDFS-14134?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16834323#comment-16834323
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Yuxuan Wang commented on HDFS-14134:
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Hi [~lukmajercak]. No. I just figure that {{StandbyException}} always trigger 
{{FAILOVER_AND_RETRY}}. And with hedging proxy, the action 
{{FAILOVER_AND_RETRY}} will always be gotten and will cover all actions have 
lower order than {{FAILOVER_AND_RETRY}}.
 I mean that the order of {{enum RetryDecision}} may should be 
{{FAILOVER_AND_RETRY < RETRY < FAIL}} in patch 007. 
Or in short, {{FAILOVER_AND_RETRY}}'s order should be the lowest.

> Idempotent operations throwing RemoteException should not be retried by the 
> client
> ----------------------------------------------------------------------------------
>
>                 Key: HDFS-14134
>                 URL: https://issues.apache.org/jira/browse/HDFS-14134
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: hdfs, hdfs-client, ipc
>            Reporter: Lukas Majercak
>            Assignee: Lukas Majercak
>            Priority: Critical
>         Attachments: HDFS-14134.001.patch, HDFS-14134.002.patch, 
> HDFS-14134.003.patch, HDFS-14134.004.patch, HDFS-14134.005.patch, 
> HDFS-14134.006.patch, HDFS-14134.007.patch, 
> HDFS-14134_retrypolicy_change_proposal.pdf, 
> HDFS-14134_retrypolicy_change_proposal_1.pdf
>
>
> Currently, some operations that throw IOException on the NameNode are 
> evaluated by RetryPolicy as FAILOVER_AND_RETRY, but they should just fail 
> fast.
> For example, when calling getXAttr("user.some_attr", file") where the file 
> does not have the attribute, NN throws an IOException with message "could not 
> find attr". The current client retry policy determines the action for that to 
> be FAILOVER_AND_RETRY. The client then fails over and retries until it 
> reaches the maximum number of retries. Supposedly, the client should be able 
> to tell that this exception is normal and fail fast. 
> Moreover, even if the action was FAIL, the RetryInvocationHandler looks at 
> all the retry actions from all requests, and FAILOVER_AND_RETRY takes 
> precedence over FAIL action.



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