title: Start token not found error while using JsonSerDe
body: <p>I am trying to import a JSON data from S3, and after making some queries, export the output as JSON format to S3 again. However, I get the <strong>"org.apache.hadoop.hive.serde2.SerDeException: java.io.IOException: Start token not found where expected"</strong> error at hive step on EMR cluster. In order to understand what the problem is, I simplify the Hive script and JSON data, but it keeps giving the same error. How can I solve this problem?</p>
  
  <p>Cluster configuration:</p>
  
  <blockquote>
    <p>Release: emr-5.3.1</p>
    
    <p>Hive version: 2.1.1 </p>
    
    <p>Hadoop distribution: Amazon 2.7.3</p>
    
    <p>Service Role: EMR_DefaultRole </p>
    
    <p>MasterInstanceType: m4.large</p>
  </blockquote>
  
  <p>The content of the simplifed JSON data:</p>
  
  <pre class="lang-json prettyprint-override"><code>[{"MyID":"FOO123","MyField":"FOO"},{"MyID":"BAR123","MyField":"BAR"}]
  </code></pre>
  
  <p>Hive script:</p>
  
  <pre class="lang-sql prettyprint-override"><code>DROP TABLE IF EXISTS SOURCE;
  DROP TABLE IF EXISTS DESTINATION;
  
  CREATE EXTERNAL TABLE SOURCE(MyID STRING, MyField STRING)
  ROW FORMAT SERDE 'org.apache.hive.hcatalog.data.JsonSerDe'
  LOCATION 's3://myPath/subPath/';
  
  CREATE EXTERNAL TABLE DESTINATION(MyID STRING, MyField STRING)                                    
  ROW FORMAT SERDE 'org.apache.hive.hcatalog.data.JsonSerDe'
  LOCATION 's3://anotherPath/subPath/';
  
  INSERT OVERWRITE TABLE DESTINATION SELECT MyID, MyField FROM SOURCE;
  </code></pre>
  
  <p>And here is the stack trace:</p>
  
  <blockquote>
    <p>Vertex failed, vertexName=Map 4, vertexId=vertex_1278452616863_0001_1_00, diagnostics=[Task failed, taskId=task_1278452616863, diagnostics=[TaskAttempt 0 failed, info=[Error: Error while running task ( failure ) : attempt_1278452616863:java.lang.RuntimeException: java.lang.RuntimeException: org.apache.hadoop.hive.ql.metadata.HiveException: Hive Runtime Error while processing writable [{"MyID":"FOO123","MyField":"FOO"},{"MyID":"BAR123","MyField":"BAR"}]
        at org.apache.hadoop.hive.ql.exec.tez.TezProcessor.initializeAndRunProcessor(TezProcessor.java:211)
        at org.apache.hadoop.hive.ql.exec.tez.TezProcessor.run(TezProcessor.java:168)
        at org.apache.tez.runtime.LogicalIOProcessorRuntimeTask.run(LogicalIOProcessorRuntimeTask.java:370)
        at org.apache.tez.runtime.task.TaskRunner2Callable$1.run(TaskRunner2Callable.java:73)
        at org.apache.tez.runtime.task.TaskRunner2Callable$1.run(TaskRunner2Callable.java:61)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1698)
        at org.apache.tez.runtime.task.TaskRunner2Callable.callInternal(TaskRunner2Callable.java:61)
        at org.apache.tez.runtime.task.TaskRunner2Callable.callInternal(TaskRunner2Callable.java:37)
        at org.apache.tez.common.CallableWithNdc.call(CallableWithNdc.java:36)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
    Caused by: java.lang.RuntimeException: org.apache.hadoop.hive.ql.metadata.HiveException: Hive Runtime Error while processing writable [{"MyID":"FOO123","MyField":"FOO"},{"MyID":"BAR123","MyField":"BAR"}]
        at org.apache.hadoop.hive.ql.exec.tez.MapRecordSource.processRow(MapRecordSource.java:95)
        at org.apache.hadoop.hive.ql.exec.tez.MapRecordSource.pushRecord(MapRecordSource.java:70)
        at org.apache.hadoop.hive.ql.exec.tez.MapRecordProcessor.run(MapRecordProcessor.java:383)
        at org.apache.hadoop.hive.ql.exec.tez.TezProcessor.initializeAndRunProcessor(TezProcessor.java:185)
        ... 14 more
    Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: Hive Runtime Error while processing writable [{"MyID":"FOO123","MyField":"FOO"},{"MyID":"BAR123","MyField":"BAR"}]
        at org.apache.hadoop.hive.ql.exec.MapOperator.process(MapOperator.java:497)
        at org.apache.hadoop.hive.ql.exec.tez.MapRecordSource.processRow(MapRecordSource.java:86)
        ... 17 more
    Caused by: org.apache.hadoop.hive.serde2.SerDeException: java.io.IOException: Start token not found where expected
        at org.apache.hive.hcatalog.data.JsonSerDe.deserialize(JsonSerDe.java:183)
        at org.apache.hadoop.hive.ql.exec.MapOperator$MapOpCtx.readRow(MapOperator.java:128)
        at org.apache.hadoop.hive.ql.exec.MapOperator$MapOpCtx.access$200(MapOperator.java:92)
        at org.apache.hadoop.hive.ql.exec.MapOperator.process(MapOperator.java:488)
        ... 18 more
    Caused by: java.io.IOException: Start token not found where expected
        at org.apache.hive.hcatalog.data.JsonSerDe.deserialize(JsonSerDe.java:169)
        ... 21 more</p>
  </blockquote>
  
  <p>Thanks.</p>