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https://issues.apache.org/jira/browse/HDFS-8220?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14652228#comment-14652228
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Rakesh R commented on HDFS-8220:
--------------------------------
bq. I saw if ( numOfDNs >= NUM_DATA_BLOCKS && numOfDNs < GROUP_SIZE ), the
OutputStream hangs and stop writing, even if the file is smaller than a
cellSize. We should fix that.
Good catch!, I've added testcase to simulate the same. Attached patch where I'm
closing the streamer which doesn't have blocklocations available.
After the execution of {{StripedDataStreamer.super.locateFollowingBlock()}}, it
will validate the data blocks length. Secondly, it does the check for {{(blocks
== null)}}. I could see {{LocatedBlock}} will be null when there is no
sufficient data node available for that index. Since we are checking for
sufficient data blocks number of DNs, those {{LocatedBlock}} will never be
empty. If there are no block locations available for parity blocks then those
blocks will become null. I've tried an approach by closing the respective
parity streamers, any thoughts?
> Erasure Coding: StripedDataStreamer fails to handle the blocklocations which
> doesn't satisfy BlockGroupSize
> -----------------------------------------------------------------------------------------------------------
>
> Key: HDFS-8220
> URL: https://issues.apache.org/jira/browse/HDFS-8220
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Rakesh R
> Assignee: Rakesh R
> Attachments: HDFS-8220-001.patch, HDFS-8220-002.patch,
> HDFS-8220-003.patch, HDFS-8220-004.patch, HDFS-8220-HDFS-7285-09.patch,
> HDFS-8220-HDFS-7285.005.patch, HDFS-8220-HDFS-7285.006.patch,
> HDFS-8220-HDFS-7285.007.patch, HDFS-8220-HDFS-7285.007.patch,
> HDFS-8220-HDFS-7285.008.patch
>
>
> During write operations {{StripedDataStreamer#locateFollowingBlock}} fails to
> validate the available datanodes against the {{BlockGroupSize}}. Please see
> the exception to understand more:
> {code}
> 2015-04-22 14:56:11,313 WARN hdfs.DFSClient (DataStreamer.java:run(538)) -
> DataStreamer Exception
> java.lang.NullPointerException
> at
> java.util.concurrent.LinkedBlockingQueue.offer(LinkedBlockingQueue.java:374)
> at
> org.apache.hadoop.hdfs.StripedDataStreamer.locateFollowingBlock(StripedDataStreamer.java:157)
> at
> org.apache.hadoop.hdfs.DataStreamer.nextBlockOutputStream(DataStreamer.java:1332)
> at org.apache.hadoop.hdfs.DataStreamer.run(DataStreamer.java:424)
> at
> org.apache.hadoop.hdfs.StripedDataStreamer.run(StripedDataStreamer.java:1)
> 2015-04-22 14:56:11,313 INFO hdfs.MiniDFSCluster
> (MiniDFSCluster.java:shutdown(1718)) - Shutting down the Mini HDFS Cluster
> 2015-04-22 14:56:11,313 ERROR hdfs.DFSClient
> (DFSClient.java:closeAllFilesBeingWritten(608)) - Failed to close inode 16387
> java.io.IOException: DataStreamer Exception:
> at org.apache.hadoop.hdfs.DataStreamer.run(DataStreamer.java:544)
> at
> org.apache.hadoop.hdfs.StripedDataStreamer.run(StripedDataStreamer.java:1)
> Caused by: java.lang.NullPointerException
> at
> java.util.concurrent.LinkedBlockingQueue.offer(LinkedBlockingQueue.java:374)
> at
> org.apache.hadoop.hdfs.StripedDataStreamer.locateFollowingBlock(StripedDataStreamer.java:157)
> at
> org.apache.hadoop.hdfs.DataStreamer.nextBlockOutputStream(DataStreamer.java:1332)
> at org.apache.hadoop.hdfs.DataStreamer.run(DataStreamer.java:424)
> ... 1 more
> {code}
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