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https://issues.apache.org/jira/browse/HDFS-7729?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14318660#comment-14318660
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Zhe Zhang commented on HDFS-7729:
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Thanks Bo for the quick rev! The overall structure looks good to me now. I'd
like more opinions on the following questions:
# We are extending several variables to arrays or lists, like {{dataQueue}},
{{currentSeqno}}, {{streamer}}. How should we handle this extension:
#* We can have a bunch of arrays/lists in the outer {{DFSOutputStream}} class.
#* Or we can convert some of them as members of {{DataStreamer}}, like the
current patch does. Following this direction, maybe {{dataQueue}} and
{{ackQueue}} can go into {{DataStreamer}} too?
#* I guess the bottom line is to have a consistent treatment for all such
variables.
# How to handle {{InterruptedException}} in {{nextBlockOutputStream}} when
offering and polling blocks to the BlockingQueue. I guess we should just
gracefully close the streamer thread.
# This change is quite complex and we should think about how to minimize risk
of breaking logics for non-striping files.
#* I will setup a branch on my personal github repo and run a Jenkins job for
the latest patch
#* Thinking out loud: shall we keep {{streamer}}, {{dataQueue}}, {{ackQueue}}
variables, and create *additional* arrays or lists for secondary streams? This
might be less intrusive on non-striping files. [~jingzhao] Could you share some
advice here?
# Testing without a striping reader is tricky. {{blocksForUnitTest}} in the
current patch is a quick and easy way around. I feel it's probably fine in a
branch commit, but would like to hear from others.
Minor items:
# Append should use the {{notSupportedInStripingLayout}} too
{code}
//Appending to a striping layout file will be supported in the next phase
if(stripingLayout)
throw new IOException("Not support appending to a striping layout file
yet.");
{code}
# There are still bracket-less statements, like in
{{notSupportedInStripingLayout}}
> Add logic to DFSOutputStream to support writing a file in striping layout
> --------------------------------------------------------------------------
>
> Key: HDFS-7729
> URL: https://issues.apache.org/jira/browse/HDFS-7729
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Li Bo
> Assignee: Li Bo
> Attachments: Codec-tmp.patch, HDFS-7729-001.patch,
> HDFS-7729-002.patch, HDFS-7729-003.patch, HDFS-7729-004.patch,
> HDFS-7729-005.patch, HDFS-7729-006.patch, HDFS-7729-007.patch,
> HDFS-7729-008.patch
>
>
> If client wants to directly write a file striping layout, we need to add some
> logic to DFSOutputStream. DFSOutputStream needs multiple DataStreamers to
> write each cell of a stripe to a remote datanode.
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