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https://issues.apache.org/jira/browse/HDFS-9040?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14934036#comment-14934036
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Jing Zhao commented on HDFS-9040:
---------------------------------
Thanks for the review, Zhe! For {{getFollowingBlock}}, currently we have:
# The {{DFSStripedOutputStream}} fetches the new block from NN when it receives
the first chunk of data for the new block. This is before we enqueue the first
packet for the new block.
# The data streamer does not call {{getFollowingBlock}} until its data queue is
no longer empty.
Thus I think when a data streamer calls {{getFollowingBlock}}, the new block
should already be ready in the queue. Therefore {{poll}} here should be safe.
Besides, if we make a mistake here, poll can give us a NPE so it may be easier
for debug.
I will update the patch to address your comments about {{callUpdatePipeline}}
and {{updatePipelineInternal}}.
> Erasure coding: Refactor DFSStripedOutputStream (Move Namenode RPC Requests
> to Coordinator)
> -------------------------------------------------------------------------------------------
>
> Key: HDFS-9040
> URL: https://issues.apache.org/jira/browse/HDFS-9040
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Walter Su
> Assignee: Jing Zhao
> Attachments: HDFS-9040-HDFS-7285.002.patch,
> HDFS-9040-HDFS-7285.003.patch, HDFS-9040-HDFS-7285.004.patch,
> HDFS-9040-HDFS-7285.005.patch, HDFS-9040-HDFS-7285.005.patch,
> HDFS-9040-HDFS-7285.006.patch, HDFS-9040.00.patch, HDFS-9040.001.wip.patch,
> HDFS-9040.02.bgstreamer.patch
>
>
> The general idea is to simplify error handling logic.
> -Proposal 1:-
> -A BlockGroupDataStreamer to communicate with NN to allocate/update block,
> and StripedDataStreamer s only have to stream blocks to DNs.-
> Proposal 2:
> See below the
> [comment|https://issues.apache.org/jira/browse/HDFS-9040?focusedCommentId=14741388&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14741388]
> from [~jingzhao].
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