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https://issues.apache.org/jira/browse/HDFS-7163?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15022684#comment-15022684
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Eric Payne commented on HDFS-7163:
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{quote}
In this patch, if the DN that is being read from goes down, WebHDFS will put
that DN into the client's URL exclude list before querying the NN again for
another DN. The only time the same DN is reused is if a seek has occurred.
{quote}
[~wheat9], I was wrong about one thing. In the current patch, a failed read
does not put the current node into the exclude list, so when the client queries
the NN again, the NN could give it the same node back. I will put up a new
patch soon addressing this issue.
> WebHdfsFileSystem should retry reads according to the configured retry policy.
> ------------------------------------------------------------------------------
>
> Key: HDFS-7163
> URL: https://issues.apache.org/jira/browse/HDFS-7163
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: webhdfs
> Affects Versions: 3.0.0, 2.5.1
> Reporter: Eric Payne
> Assignee: Eric Payne
> Attachments: HDFS-7163-branch-2.003.patch,
> HDFS-7163-branch-2.7.003.patch, HDFS-7163.001.patch, HDFS-7163.002.patch,
> HDFS-7163.003.patch, WebHDFS Read Retry.pdf
>
>
> In the current implementation of WebHdfsFileSystem, opens are retried
> according to the configured retry policy, but not reads. Therefore, if a
> connection goes down while data is being read, the read will fail and the
> read will have to be retried by the client code.
> Also, after a connection has been established, the next read (or seek/read)
> will fail and the read will have to be restarted by the client code.
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