Incorrect results of aggregation with grouping sets with single target partition #16965
Description
Describe the bug
When datafusion.execution.target_partitions is set to 1 then following query gives incorrect results -- select id from (select 'id' as id union all select 'id' as id order by id) group by grouping sets ((id), ());
To Reproduce
Run following in datafusion-cli
DataFusion CLI v49.0.0
> set datafusion.execution.target_partitions = 1;
0 row(s) fetched.
Elapsed 0.013 seconds.
> select id from (select 'id' as id union all select 'id' as id order by id) group by grouping sets ((id), ());
+------+
| id |
+------+
| id |
| NULL |
| id |
+------+
3 row(s) fetched.
Elapsed 0.016 seconds.
Expected behavior
Query should give following result
+------+
| id |
+------+
| id |
| NULL |
+------+
Additional context
Postgres gives following
psql (17.5 (Homebrew))
Type "help" for help.
postgres=# select id from (select 'id' as id union all select 'id' as id) group by grouping sets ((id), ());
id
----
id
(2 rows)