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https://issues.apache.org/jira/browse/HDFS-9103?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14901077#comment-14901077
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Haohui Mai commented on HDFS-9103:
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bq. I think it is important to have a high-level C++ "go read this data" API
that provides a simple async API for reading that embodies good default
policies for failure recovery and cross-block reading. It makes sense to keep
them composible; I will re-work AsycPreadSome to push the ignored node scope
into the ephemeral state and have it managed by the reliable read method.
An "easy" version of APIs are definitely beneficial but it's important to have
APIs that exposes all information for maximal flexibility. Also note that the
C++ APIs are unstable and the C layer are well-defined, my hope is to land this
functionality on the C compatibility layer first.
> Retry reads on DN failure
> -------------------------
>
> Key: HDFS-9103
> URL: https://issues.apache.org/jira/browse/HDFS-9103
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: Bob Hansen
> Assignee: Bob Hansen
> Fix For: HDFS-8707
>
> Attachments: HDFS-9103.1.patch, HDFS-9103.2.patch
>
>
> When AsyncPreadSome fails, add the failed DataNode to the excluded list and
> try again.
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