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https://issues.apache.org/jira/browse/HDFS-8287?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14744015#comment-14744015
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Jing Zhao commented on HDFS-8287:
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Thanks for working on this, [~kaisasak] and [~szetszwo]! The current patch
looks good to me. Some comments:
# Looks like the current wait() and notifyAll() are called by the same thread?
I think the rollBuffers and processFuture related code can be simplified by
utilizing CompletionService#take and/or CompletionService#poll. Also maybe in
this way we do not need to use whether bufReady is null to indicate whether
encoding is done. The simplified logic can be:
#* Everytime we should write parity cells (already got one stripe of data or
the close is called), call CompletionService#take to wait and retrieve the
result of the last time submitted encoding task.
#* If not close, switch the buffer and submit the new encoding task.
#* If to close, use bufCurrent to encode.
# Maybe we can move CellBuffers and DoubleCellBuffer out of
DFSStripedOutputStream as standalone classes? CellBuffers can be included
inside of the DoubleCellBuffer.
> DFSStripedOutputStream.writeChunk should not wait for writing parity
> ---------------------------------------------------------------------
>
> Key: HDFS-8287
> URL: https://issues.apache.org/jira/browse/HDFS-8287
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: Tsz Wo Nicholas Sze
> Assignee: Kai Sasaki
> Attachments: HDFS-8287-HDFS-7285.00.patch,
> HDFS-8287-HDFS-7285.01.patch, HDFS-8287-HDFS-7285.02.patch,
> HDFS-8287-HDFS-7285.03.patch, HDFS-8287-HDFS-7285.04.patch,
> HDFS-8287-HDFS-7285.05.patch, HDFS-8287-HDFS-7285.06.patch,
> HDFS-8287-HDFS-7285.07.patch, HDFS-8287-HDFS-7285.08.patch,
> HDFS-8287-HDFS-7285.09.patch, HDFS-8287-HDFS-7285.WIP.patch,
> h8287_20150911.patch, jstack-dump.txt
>
>
> When a stripping cell is full, writeChunk computes and generates parity
> packets. It sequentially calls waitAndQueuePacket so that user client cannot
> continue to write data until it finishes.
> We should allow user client to continue writing instead but not blocking it
> when writing parity.
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