[DRILL-1673] Flatten function can not work well with nested arrays.

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.7.0
• Fix Version/s: 1.1.0
• Component/s: Functions - Drill

Environment

0.7.0

• Assignee: Jason Altekruse
• Reporter: Hao Zhu
• Created: 10/Nov/14 20:17
• Updated: 02/Jul/15 17:39
• Resolved: 30/Jun/15 01:00

Description

Flatten function failed to scan nested arrays , for example something like ""[[ ]]"".

The only difference of JSON files between below 2 tests is
"num":[1,2,3]
VS
"num":[[1,2,3]]

==============Test 1 (Works well):==============
file:

{"fixed_column":"abc", "list_column":[{"id1":"1","name":"zhu", "num": [1,2,3]}, {"id1":"2","name":"hao", "num": [4,5,6]} ]}

SQL:

0: jdbc:drill:zk=local> select t.`fixed_column` as fixed_column, flatten(t.`list_column`)  from dfs.root.`/Users/hzu/Documents/sharefolder/hp/n2.json` as t;
+--------------+------------+
| fixed_column |   EXPR$1   |
+--------------+------------+
| abc          | {"id1":"1","name":"zhu","num":[1,2,3]} |
| abc          | {"id1":"2","name":"hao","num":[4,5,6]} |
+--------------+------------+
2 rows selected (0.154 seconds)

==============Test 2 (Failed):==============
file:

{"fixed_column":"abc", "list_column":[{"id1":"1","name":"zhu", "num": [[1,2,3]]}, {"id1":"2","name":"hao", "num": [[4,5,6]]} ]}

SQL:

0: jdbc:drill:zk=local>  select t.`fixed_column` as fixed_column, flatten(t.`list_column`)  from dfs.root.`/Users/hzu/Documents/sharefolder/hp/n3.json` as t;
+--------------+------------+
| fixed_column |   EXPR$1   |
+--------------+------------+
Query failed: Failure while running fragment.[ df28347b-fac1-497d-b9c5-a313ba77aa4d on 10.250.0.115:31010 ]
  (java.lang.UnsupportedOperationException) 
    org.apache.drill.exec.vector.complex.RepeatedListVector$RepeatedListTransferPair.splitAndTransfer():339
    org.apache.drill.exec.vector.complex.RepeatedMapVector$SingleMapTransferPair.splitAndTransfer():305
    org.apache.drill.exec.test.generated.FlattenerGen22.flattenRecords():93
    org.apache.drill.exec.physical.impl.flatten.FlattenRecordBatch.doWork():152
    org.apache.drill.exec.record.AbstractSingleRecordBatch.innerNext():89
    org.apache.drill.exec.physical.impl.flatten.FlattenRecordBatch.innerNext():118
    org.apache.drill.exec.record.AbstractRecordBatch.next():106
    org.apache.drill.exec.physical.impl.validate.IteratorValidatorBatchIterator.next():124
    org.apache.drill.exec.record.AbstractRecordBatch.next():86
    org.apache.drill.exec.record.AbstractRecordBatch.next():76
    org.apache.drill.exec.record.AbstractSingleRecordBatch.innerNext():52
    org.apache.drill.exec.physical.impl.project.ProjectRecordBatch.innerNext():129
    org.apache.drill.exec.record.AbstractRecordBatch.next():106
    org.apache.drill.exec.physical.impl.validate.IteratorValidatorBatchIterator.next():124
    org.apache.drill.exec.physical.impl.BaseRootExec.next():67
    org.apache.drill.exec.physical.impl.ScreenCreator$ScreenRoot.innerNext():122
    org.apache.drill.exec.physical.impl.BaseRootExec.next():57
    org.apache.drill.exec.work.fragment.FragmentExecutor.run():105
    org.apache.drill.exec.work.WorkManager$RunnableWrapper.run():249
    .......():0


java.lang.RuntimeException: java.sql.SQLException: Failure while executing query.
	at sqlline.SqlLine$IncrementalRows.hasNext(SqlLine.java:2514)
	at sqlline.SqlLine$TableOutputFormat.print(SqlLine.java:2148)
	at sqlline.SqlLine.print(SqlLine.java:1809)
	at sqlline.SqlLine$Commands.execute(SqlLine.java:3766)
	at sqlline.SqlLine$Commands.sql(SqlLine.java:3663)
	at sqlline.SqlLine.dispatch(SqlLine.java:889)
	at sqlline.SqlLine.begin(SqlLine.java:763)
	at sqlline.SqlLine.start(SqlLine.java:498)
	at sqlline.SqlLine.main(SqlLine.java:460)

Issue Links

• is related to: DRILL-1753 Flatten fails on a repeated map, where the maps being flattened contain repeated lists