[DRILL-2256] Flatten on an empty list fails.

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Assignee: Unassigned
• Reporter: Hanifi Gunes
• Created: 17/Feb/15 19:02
• Updated: 20/Feb/15 20:04
• Resolved: 20/Feb/15 20:04

Description

Running

select flatten(empty) from data.json

on

data.json

{"empty": [ [] ] }

fails with

java.lang.NullPointerException
	at org.apache.drill.exec.vector.complex.RepeatedListVector$RepeatedListTransferPair.<init>(RepeatedListVector.java:273) ~[classes/:na]
	at org.apache.drill.exec.vector.complex.RepeatedListVector$RepeatedListTransferPair.<init>(RepeatedListVector.java:265) ~[classes/:na]
	at org.apache.drill.exec.vector.complex.RepeatedListVector.makeTransferPair(RepeatedListVector.java:322) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.project.ProjectRecordBatch.setupNewSchema(ProjectRecordBatch.java:406) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractSingleRecordBatch.innerNext(AbstractSingleRecordBatch.java:78) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.project.ProjectRecordBatch.innerNext(ProjectRecordBatch.java:134) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractRecordBatch.next(AbstractRecordBatch.java:142) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.validate.IteratorValidatorBatchIterator.next(IteratorValidatorBatchIterator.java:118) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractRecordBatch.next(AbstractRecordBatch.java:99) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractRecordBatch.next(AbstractRecordBatch.java:89) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractSingleRecordBatch.innerNext(AbstractSingleRecordBatch.java:51) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.flatten.FlattenRecordBatch.innerNext(FlattenRecordBatch.java:122) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractRecordBatch.next(AbstractRecordBatch.java:142) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.validate.IteratorValidatorBatchIterator.next(IteratorValidatorBatchIterator.java:118) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractRecordBatch.next(AbstractRecordBatch.java:99) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractRecordBatch.next(AbstractRecordBatch.java:89) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractSingleRecordBatch.innerNext(AbstractSingleRecordBatch.java:51) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.project.ProjectRecordBatch.innerNext(ProjectRecordBatch.java:134) ~[classes/:na]
	at org.apache.drill.exec.record.AbstractRecordBatch.next(AbstractRecordBatch.java:142) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.validate.IteratorValidatorBatchIterator.next(IteratorValidatorBatchIterator.java:118) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.BaseRootExec.next(BaseRootExec.java:67) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.ScreenCreator$ScreenRoot.innerNext(ScreenCreator.java:97) ~[classes/:na]
	at org.apache.drill.exec.physical.impl.BaseRootExec.next(BaseRootExec.java:57) ~[classes/:na]
	at org.apache.drill.exec.work.fragment.FragmentExecutor.run(FragmentExecutor.java:116) ~[classes/:na]
	at org.apache.drill.exec.work.WorkManager$RunnableWrapper.run(WorkManager.java:303) [classes/:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_65]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_65]
	at java.lang.Thread.run(Thread.java:745) [na:1.7.0_65]

I believe, flatten should have output as many nulls as the number of existing records/rows.

Issue Links

• duplicates: DRILL-2217 Trying to flatten an empty list should return an empty result