Description
HoS doesn't trigger map-joins for the following query:
EXPLAIN SELECT * FROM (SELECT part_col FROM partitioned_table1 UNION ALL SELECT part_col FROM partitioned_table2) q1 JOIN regular_table1 JOIN regular_table2 WHERE q1.part_col = regular_table1.col1 AND q1.part_col = regular_table2.col1;
Hive-on-Tez does.