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https://issues.apache.org/jira/browse/HDFS-12638?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Konstantin Shvachko updated HDFS-12638:
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Attachment: HDFS-12638.003.patch
We digged with Erik through a lot of code and history. I agree that 002 patch
fixes the problem without reverting HDFS-9754. The culprit that caused the NPE
is this change from HDFS-9754:
{code}
- BlockCollection bc = getBlockCollection(block);
- if (bc == null
- || (bc.isUnderConstruction() && block.equals(bc.getLastBlock()))) {
+ // skip abandoned block or block reopened for append
+ if (block.isDeleted() || !block.isCompleteOrCommitted()) {
{code}
Since truncateBlock is not marked as deleted {{validateReconstructionWork()}}
does not go into return inside if, but rather proceeds. It then hits the NPE as
block collections is null since the corresponding INode was deleted.
I am attaching new patch, which combines 002, and slightly modified test case
from [~yangjiandan]'s 001 patch.
Please review.
> NameNode exits due to ReplicationMonitor thread received Runtime exception in
> ReplicationWork#chooseTargets
> -----------------------------------------------------------------------------------------------------------
>
> Key: HDFS-12638
> URL: https://issues.apache.org/jira/browse/HDFS-12638
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs
> Affects Versions: 2.8.2
> Reporter: Jiandan Yang
> Priority: Blocker
> Attachments: HDFS-12638-branch-2.8.2.001.patch, HDFS-12638.002.patch,
> HDFS-12638.003.patch, OphanBlocksAfterTruncateDelete.jpg
>
>
> Active NamNode exit due to NPE, I can confirm that the BlockCollection passed
> in when creating ReplicationWork is null, but I do not know why
> BlockCollection is null, By view history I found
> [HDFS-9754|https://issues.apache.org/jira/browse/HDFS-9754] remove judging
> whether BlockCollection is null.
> NN logs are as following:
> {code:java}
> 2017-10-11 16:29:06,161 ERROR [ReplicationMonitor]
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager:
> ReplicationMonitor thread received Runtime exception.
> java.lang.NullPointerException
> at
> org.apache.hadoop.hdfs.server.blockmanagement.ReplicationWork.chooseTargets(ReplicationWork.java:55)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.computeReplicationWorkForBlocks(BlockManager.java:1532)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.computeReplicationWork(BlockManager.java:1491)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.computeDatanodeWork(BlockManager.java:3792)
> at
> org.apache.hadoop.hdfs.server.blockmanagement.BlockManager$ReplicationMonitor.run(BlockManager.java:3744)
> at java.lang.Thread.run(Thread.java:834)
> {code}
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