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  1. Hadoop HDFS
  2. HDFS-12416

BlockPlacementPolicyDefault will cause NN shutdown if log level is changed

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Duplicate
    • Affects Version/s: 2.7.4, 3.0.0-alpha3
    • Fix Version/s: None
    • Component/s: block placement
    • Labels:
      None

      Description

      In BlockPlacementPolicyDefault.chooseRandom method.
      The code are in below structure:

      StringBuilder builder = null;
          if (LOG.isDebugEnabled()) {
            builder = debugLoggingBuilder.get();
            builder.setLength(0);
            builder.append("[");
          }
      while(numOfReplicas > 0){
      .............
      chooseDataNode(scope, excludedNodes)
      .............
      if (LOG.isDebugEnabled()) {
              builder.append("\nNode ").append(NodeBase.getPath(chosenNode))
                  .append(" [");
            }
      }
      

      There's a possibility that the loglevel is INFO before entering while loop, but the loglevel is changed to DEBUG inside the loop through web UI.
      In that case, builder is not initialized in the beginning and NullPointerException will throw and this will cause NN exiting.

        Attachments

        1. HDFS-12416.001.patch
          2 kB
          Suhan Mao
        2. HDFS-12416.patch
          2 kB
          Suhan Mao

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              • Assignee:
                Unassigned
                Reporter:
                smao Suhan Mao
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