[DRILL-6606] Hash Join returns incorrect data types when joining subqueries with limit 0

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 1.14.0
• Labels: ready-to-commit
• Assignee: Timothy Farkas
• Reporter: Bohdan Kazydub
• Reviewer: Boaz Ben-Zvi
• Created: 13/Jul/18 10:42
• Updated: 21/Jul/18 00:24
• Resolved: 21/Jul/18 00:24

Description

PreparedStatement for query

SELECT l.l_quantity, l.l_shipdate, o.o_custkey
FROM (SELECT * FROM cp.`tpch/lineitem.parquet` LIMIT 0) l
    JOIN (SELECT * FROM cp.`tpch/orders.parquet` LIMIT 0) o 
    ON l.l_orderkey = o.o_orderkey
LIMIT 0

 is created with wrong types (nullable INTEGER) for all selected columns, no matter what their actual type is. This behavior reproduces with hash join only and is very likely to be caused by DRILL-6027 as the query works fine before this feature was implemented.

To reproduce the problem you can put the aforementioned query into TestPreparedStatementProvider#joinOrderByQuery() test method.

Issue Links

• Blocked: DRILL-6574 Add option to push LIMIT(0) on top of SCAN (late limit 0 optimization)
• is caused by: DRILL-6027 Implement spill to disk for the Hash Join
• links to: GitHub Pull Request #1384