[DRILL-4783] Flatten on CONVERT_FROM fails with ClassCastException if resultset is empty

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 1.8.0
• Assignee: Chunhui Shi
• Reporter: Chunhui Shi
• Reviewer: Rahul Kumar Challapalli
• Created: 16/Jul/16 01:42
• Updated: 18/Aug/16 17:34
• Resolved: 22/Jul/16 23:36

Description

Flatten failed to work on top of convert_from when the resultset is empty.

For a HBase table like this:

0: jdbc:drill:zk=localhost:5181> select convert_from(t.address.cities,'json') from hbase.`/tmp/flattentest` t;
----------------------------------------------------------------------------------

EXPR$0

----------------------------------------------------------------------------------

{"list":[{"city":"SunnyVale"},{"city":"Palo Alto"},{"city":"Mountain View"}]}

{"list":[{"city":"Seattle"},{"city":"Bellevue"},{"city":"Renton"}]}

{"list":[{"city":"Minneapolis"},{"city":"Falcon Heights"},{"city":"San Paul"}]}

----------------------------------------------------------------------------------

Flatten works when row_key is in (1,2,3)
0: jdbc:drill:zk=localhost:5181> select flatten(t1.json.list) from (select convert_from(t.address.cities,'json') json from hbase.`/tmp/flattentest` t where row_key=1) t1;
---------------------------

EXPR$0

---------------------------

{"city":"SunnyVale"}

{"city":"Palo Alto"}

{"city":"Mountain View"}

---------------------------

But Flatten throws exception if the resultset is empty

0: jdbc:drill:zk=localhost:5181> select flatten(t1.json.list) from (select convert_from(t.address.cities,'json') json from hbase.`/tmp/flattentest` t where row_key=4) t1;
Error: SYSTEM ERROR: ClassCastException: Cannot cast org.apache.drill.exec.vector.NullableIntVector to org.apache.drill.exec.vector.complex.RepeatedValueVector

Fragment 0:0

[Error Id: 07fd0cab-d1e6-4259-bfec-ad80f02d93a2 on atsqa4-127.qa.lab:31010] (state=,code=0)

Issue Links

• links to: GitHub Pull Request #546