[PIG-5116] Pig Job failed because ConcurrentModificationException() arised

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.16.0

Environment

Mac OSX 10.11.6 El Capitan

• Assignee: Unassigned
• Reporter: Fabrizio Massara
• Created: 27/Jan/17 11:30
• Updated: 01/Feb/17 05:09

Description

Hello, I'm trying to run a Pig Job that have to do a FULL Join over two large datasets. I'm running in local mode and I'm testing it on a very limited part of the datasets.
I started with a LIMIT of 5000 and it worked, after that I tried with a LIMIT of 10000 and the job failed. It arised this error:

2017-01-27 10:56:14,197 [Thread-1516] WARN  org.apache.hadoop.mapred.LocalJobRunner - job_local1966159905_0005
java.lang.Exception: java.io.IOException: java.io.IOException: java.util.ConcurrentModificationException
	at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:462)
	at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:529)
Caused by: java.io.IOException: java.io.IOException: java.util.ConcurrentModificationException
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapReduce$Reduce.runPipeline(PigGenericMapReduce.java:470)
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapReduce$Reduce.processOnePackageOutput(PigGenericMapReduce.java:433)
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapReduce$Reduce.reduce(PigGenericMapReduce.java:413)
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapReduce$Reduce.reduce(PigGenericMapReduce.java:262)
	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.LocalJobRunner$Job$ReduceTaskRunnable.run(LocalJobRunner.java:319)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.io.IOException: java.util.ConcurrentModificationException
	at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.StoreFuncDecorator.putNext(StoreFuncDecorator.java:83)
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat$PigRecordWriter.write(PigOutputFormat.java:144)
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigOutputFormat$PigRecordWriter.write(PigOutputFormat.java:97)
	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$Reduce.runPipeline(PigGenericMapReduce.java:468)
	... 12 more
Caused by: java.util.ConcurrentModificationException
	at java.util.Hashtable$Enumerator.next(Hashtable.java:1367)
	at org.apache.pig.data.BinInterSedes.writeMap(BinInterSedes.java:616)
	at org.apache.pig.data.BinInterSedes.writeDatum(BinInterSedes.java:478)
	at org.apache.pig.data.BinInterSedes.writeDatum(BinInterSedes.java:462)
	at org.apache.pig.data.utils.SedesHelper.writeGenericTuple(SedesHelper.java:135)
	at org.apache.pig.data.BinInterSedes.writeTuple(BinInterSedes.java:650)
	at org.apache.pig.data.BinInterSedes.writeDatum(BinInterSedes.java:470)
	at org.apache.pig.data.BinInterSedes.writeDatum(BinInterSedes.java:462)
	at org.apache.pig.impl.io.InterRecordWriter.write(InterRecordWriter.java:73)
	at org.apache.pig.impl.io.InterStorage.putNext(InterStorage.java:88)
	at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.StoreFuncDecorator.putNext(StoreFuncDecorator.java:75)
	... 18 more