[DRILL-4693] Incorrect column ordering when CONVERT_FROM() json is used

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.6.0
• Fix Version/s: 1.7.0
• Component/s: Execution - Relational Operators, Query Planning & Optimization
• Assignee: Aman Sinha
• Reporter: Aman Sinha
• Reviewer: Chun Chang
• Created: 25/May/16 15:37
• Updated: 14/Jul/16 22:38
• Resolved: 29/Jun/16 14:04

Description

For the following query, the column order in the results is wrong..it should be col1, col2, col3.

0: jdbc:drill:zk=local> select 'abc' as col1, convert_from('{"x" : "y"}', 'json') as col2, 'xyz' as col3 from cp.`tpch/region.parquet`;
+-------+-------+------------+
| col1  | col3  |    col2    |
+-------+-------+------------+
| abc   | xyz   | {"x":"y"}  |
| abc   | xyz   | {"x":"y"}  |
| abc   | xyz   | {"x":"y"}  |
| abc   | xyz   | {"x":"y"}  |
| abc   | xyz   | {"x":"y"}  |
+-------+-------+------------+

The EXPLAIN plan:

0: jdbc:drill:zk=local> explain plan for select 'abc' as col1, convert_from('{"x" : "y"}', 'json') as col2, 'xyz' as col3 from cp.`tpch/region.parquet`;
+------+------+
| text | json |
+------+------+
| 00-00    Screen
00-01      Project(col1=['abc'], col2=[CONVERT_FROMJSON('{"x" : "y"}')], col3=['xyz'])
00-02        Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=classpath:/tpch/region.parquet]], selectionRoot=classpath:/tpch/region.parquet, numFiles=1, usedMetadataFile=false, columns=[]]])

This happens on current master branch as well as 1.6.0 and even earlier (I checked 1.4.0 as well which also has the same behavior). So it is a pre-existing bug.

Issue Links

• links to: GitHub Pull Request #508