Wei-Chiu Chuang created HDFS-11260:
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             Summary: Slow writer threads are not stopped
                 Key: HDFS-11260
                 URL: https://issues.apache.org/jira/browse/HDFS-11260
             Project: Hadoop HDFS
          Issue Type: Bug
          Components: datanode
    Affects Versions: 2.7.0
            Reporter: Wei-Chiu Chuang


If a DataNode receives a transferred block, it tries to stop writer to the same 
block. However, this may not work, and we saw the following error message and 
stacktrace.

Fundamentally, the assumption of {{ReplicaInPipeline#stopWriter}} is wrong. It 
assumes the writer thread must be a DataXceiver thread, which it can be 
interrupted and terminates afterwards. However, IPC threads may also be the 
writer thread by calling initReplicaRecovery, and which ignores interrupt and 
do not terminate. 

{noformat}
2016-12-16 19:58:56,167 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: 
Join on writer thread Thread[IPC Server handler 6 on 50020,5,main] timed out
sun.misc.Unsafe.park(Native Method)
java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:226)
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2082)
java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
org.apache.hadoop.ipc.CallQueueManager.take(CallQueueManager.java:135)
org.apache.hadoop.ipc.Server$Handler.run(Server.java:2052)

2016-12-16 19:58:56,167 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: 
IOException in BlockReceiver constructor. Cause is
2016-12-16 19:58:56,168 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: 
sj1dra082.corp.adobe.com:50010:DataXceiver error processing WRITE_BLOCK 
operation  src: /10.10.0.80:44105 dst: /10.10.0.82:50010
java.io.IOException: Join on writer thread Thread[IPC Server handler 6 on 
50020,5,main] timed out
        at 
org.apache.hadoop.hdfs.server.datanode.ReplicaInPipeline.stopWriter(ReplicaInPipeline.java:212)
        at 
org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl.createTemporary(FsDatasetImpl.java:1579)
        at 
org.apache.hadoop.hdfs.server.datanode.BlockReceiver.<init>(BlockReceiver.java:195)
        at 
org.apache.hadoop.hdfs.server.datanode.DataXceiver.writeBlock(DataXceiver.java:669)
        at 
org.apache.hadoop.hdfs.protocol.datatransfer.Receiver.opWriteBlock(Receiver.java:169)
        at 
org.apache.hadoop.hdfs.protocol.datatransfer.Receiver.processOp(Receiver.java:106)
        at 
org.apache.hadoop.hdfs.server.datanode.DataXceiver.run(DataXceiver.java:246)
        at java.lang.Thread.run(Thread.java:745)
{noformat}

There is also a logic error in FsDatasetImpl#createTemporary, in which if the 
code in the synchronized block executes for more than 60 seconds (in theory), 
it could throw an exception, without trying to stop the existing slow writer.

We saw a FsDatasetImpl#createTemporary failed after nearly 10 minutes, and it's 
unclear why yet.
{noformat}
2016-12-16 23:12:24,636 WARN 
org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl: Unable to 
stop existing writer for block 
BP-1527842723-10.0.0.180-1367984731269:blk_4313782210_1103780331023 after 
568320 miniseconds.
{noformat}



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