Start token not found error while using JsonSerDe

Question

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 "org.apache.hadoop.hive.serde2.SerDeException: java.io.IOException: Start token not found where expected" 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?

Cluster configuration:

Release: emr-5.3.1

Hive version: 2.1.1

Hadoop distribution: Amazon 2.7.3

Service Role: EMR_DefaultRole

MasterInstanceType: m4.large

The content of the simplifed JSON data:

[{"MyID":"FOO123","MyField":"FOO"},{"MyID":"BAR123","MyField":"BAR"}]

Hive script:

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;

And here is the stack trace:

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

Thanks.

Answer 1

JSON should start with { and not with array ([)