Aggregation functions returning empty rows on partitioned columns

DROP TABLE IF EXISTS test;

CREATE TABLE test (a int) 
PARTITIONED BY (b int) 
ROW FORMAT DELIMITED FIELDS TERMINATED BY '|' 
TBLPROPERTIES('skip.header.line.count'='1');

INSERT OVERWRITE TABLE test PARTITION (b = 1) VALUES (1), (2), (3), (4);
INSERT OVERWRITE TABLE test PARTITION (b = 2) VALUES (1), (2), (3), (4);

SELECT * FROM test;

SELECT DISTINCT b FROM test;
SELECT MAX(b) FROM test;
SELECT DISTINCT a FROM test;

0: jdbc:hive2://localhost:10000/default> SELECT * FROM test;
+---------+---------+--+
| test.a  | test.b  |
+---------+---------+--+
| 2       | 1       |
| 3       | 1       |
| 4       | 1       |
| 2       | 2       |
| 3       | 2       |
| 4       | 2       |
+---------+---------+--+
6 rows selected (0.631 seconds)

0: jdbc:hive2://localhost:10000/default> SELECT DISTINCT b FROM test;
+----+--+
| b  |
+----+--+
+----+--+
No rows selected (47.229 seconds)

0: jdbc:hive2://localhost:10000/default> SELECT MAX(b) FROM test;
+-------+--+
|  _c0  |
+-------+--+
| NULL  |
+-------+--+
1 row selected (49.508 seconds)

0: jdbc:hive2://localhost:10000/default> SELECT DISTINCT a FROM test;
+----+--+
| a  |
+----+--+
| 2  |
| 3  |
| 4  |
+----+--+
3 rows selected (46.859 seconds)