Hadoop Batch Ingestion task is failing with java.util.NoSuchElementException

Hi,

We are receiving the following error while indexing using hadoop and using hdfs as deep storage.

After going through the code looks like this exception will come when the druid_tasklocks table have no entry for the task.

But did find any exception in overlord logs.

Here is the exception trace :

2016-10-03T11:25:05,679 ERROR [task-runner-0-priority-0] io.druid.indexing.overlord.ThreadPoolTaskRunner - Exception while running task[HadoopIndexTask{id=index_hadoop_prism-data-15_2016-10-03T10:59:46.123Z, type=index_hadoop, dataSource=prism-data-15}]

java.util.NoSuchElementException

at java.util.ArrayList$Itr.next(ArrayList.java:854) ~[?:1.8.0_101]

at com.google.common.collect.Iterators.getOnlyElement(Iterators.java:297) ~[guava-16.0.1.jar:?]

at com.google.common.collect.Iterables.getOnlyElement(Iterables.java:285) ~[guava-16.0.1.jar:?]

at io.druid.indexing.common.task.HadoopIndexTask.run(HadoopIndexTask.java:202) ~[druid-indexing-service-0.9.2-rc1.jar:0.9.2-rc1]

at io.druid.indexing.overlord.ThreadPoolTaskRunner$ThreadPoolTaskRunnerCallable.call(ThreadPoolTaskRunner.java:436) [druid-indexing-service-0.9.2-rc1.jar:0.9.2-rc1]

at io.druid.indexing.overlord.ThreadPoolTaskRunner$ThreadPoolTaskRunnerCallable.call(ThreadPoolTaskRunner.java:408) [druid-indexing-service-0.9.2-rc1.jar:0.9.2-rc1]

at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_101]

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_101]

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_101]

at java.lang.Thread.run(Thread.java:745) [?:1.8.0_101]

Hi,

Did you ever find the root cause for this issue. We are running into this issue intermittently and not sure where to start looking or how to go about debugging it. Thanks a lot!