[HIVE-11470] NPE in DynamicPartFileRecordWriterContainer on null part-keys.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.0
• Fix Version/s: 1.2.2, 2.0.0
• Component/s: HCatalog
• Assignee: Mithun Radhakrishnan
• Reporter: Mithun Radhakrishnan
• Created: 05/Aug/15 18:45
• Updated: 02/Jun/16 18:15
• Resolved: 21/Jan/16 22:49

Description

When partitioning data using HCatStorer, one sees the following NPE, if the dyn-part-key is of null-value:

2015-07-30 23:59:59,627 WARN [main] org.apache.hadoop.mapred.YarnChild: Exception running child : java.io.IOException: java.lang.NullPointerException
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapReduce$Reduce.runPipeline(PigGenericMapReduce.java:473)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapReduce$Reduce.processOnePackageOutput(PigGenericMapReduce.java:436)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapReduce$Reduce.reduce(PigGenericMapReduce.java:416)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapReduce$Reduce.reduce(PigGenericMapReduce.java:256)
at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:171)
at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:627)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:389)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:163)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1694)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)
Caused by: java.lang.NullPointerException
at org.apache.hive.hcatalog.mapreduce.DynamicPartitionFileRecordWriterContainer.getLocalFileWriter(DynamicPartitionFileRecordWriterContainer.java:141)
at org.apache.hive.hcatalog.mapreduce.FileRecordWriterContainer.write(FileRecordWriterContainer.java:110)
at org.apache.hive.hcatalog.mapreduce.FileRecordWriterContainer.write(FileRecordWriterContainer.java:54)
at org.apache.hive.hcatalog.pig.HCatBaseStorer.putNext(HCatBaseStorer.java:309)
at org.apache.hive.hcatalog.pig.HCatStorer.putNext(HCatStorer.java:61)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat$PigRecordWriter.write(PigOutputFormat.java:139)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat$PigRecordWriter.write(PigOutputFormat.java:98)
at org.apache.hadoop.mapred.ReduceTask$NewTrackingRecordWriter.write(ReduceTask.java:558)
at org.apache.hadoop.mapreduce.task.TaskInputOutputContextImpl.write(TaskInputOutputContextImpl.java:89)
at org.apache.hadoop.mapreduce.lib.reduce.WrappedReducer$Context.write(WrappedReducer.java:105)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapReduce$Reduce.runPipeline(PigGenericMapReduce.java:471)
... 11 more

The reason is that the DynamicPartitionFileRecordWriterContainer makes an unfortunate assumption when fetching a local file-writer instance:

DynamicPartitionFileRecordWriterContainer.java

  @Override
  protected LocalFileWriter getLocalFileWriter(HCatRecord value) 
    throws IOException, HCatException {
    
    OutputJobInfo localJobInfo = null;
    // Calculate which writer to use from the remaining values - this needs to
    // be done before we delete cols.
    List<String> dynamicPartValues = new ArrayList<String>();
    for (Integer colToAppend : dynamicPartCols) {
      dynamicPartValues.add(value.get(colToAppend).toString()); // <-- YIKES!
    }
    ...
  }

Must check for null, and substitute with "__HIVE_DEFAULT_PARTITION__", or equivalent.