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Posted to hdfs-dev@hadoop.apache.org by "Zhu Guangbin (JIRA)" <ji...@apache.org> on 2016/08/02 08:11:20 UTC

[jira] [Created] (HDFS-10715) NPE

Zhu Guangbin created HDFS-10715:
-----------------------------------

             Summary: NPE 
                 Key: HDFS-10715
                 URL: https://issues.apache.org/jira/browse/HDFS-10715
             Project: Hadoop HDFS
          Issue Type: Bug
          Components: namenode
    Affects Versions: 2.8.0
         Environment: cdh5.8.0
            Reporter: Zhu Guangbin


As HDFS-8131 introduced an AvailableSpaceBlockPlacementPolicy, but In some cases, it caused NPE. 

Here are my namenode daemon logs : 

2016-08-02 13:05:03,271 WARN org.apache.hadoop.ipc.Server: IPC Server handler 13 on 8020, call org.apache.hadoop.hdfs.protocol.ClientProtocol.addBlock from 10.132.89.79:14001 Call#56 Retry#0
java.lang.NullPointerException
        at org.apache.hadoop.hdfs.server.blockmanagement.AvailableSpaceBlockPlacementPolicy.compareDataNode(AvailableSpaceBlockPlacementPolicy.java:95)
        at org.apache.hadoop.hdfs.server.blockmanagement.AvailableSpaceBlockPlacementPolicy.chooseDataNode(AvailableSpaceBlockPlacementPolicy.java:80)
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseRandom(BlockPlacementPolicyDefault.java:691)
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseRandom(BlockPlacementPolicyDefault.java:665)
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseLocalRack(BlockPlacementPolicyDefault.java:572)
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseTargetInOrder(BlockPlacementPolicyDefault.java:457)
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseTarget(BlockPlacementPolicyDefault.java:367)
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseTarget(BlockPlacementPolicyDefault.java:242)
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseTarget(BlockPlacementPolicyDefault.java:114)
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseTarget(BlockPlacementPolicyDefault.java:130)
        at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget4NewBlock(BlockManager.java:1606)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalBlock(FSNamesystem.java:3315)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.addBlock(NameNodeRpcServer.java:679)
        at org.apache.hadoop.hdfs.server.namenode.AuthorizationProviderProxyClientProtocol.addBlock(AuthorizationProviderProxyClientProtocol.java:214)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.addBlock(ClientNamenodeProtocolServerSideTranslatorPB.java:489)
        at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:617)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1073)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2086)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2082)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1693)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2080)

I reviewed the source code, and found the bug in method chooseDataNode. clusterMap.chooseRandom may return null, which cannot compare using equals a.equals(b) method.  

Though this exception can be caught, and then retry another call. I think this bug should be fixed.



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