[HIVE-2992] JOIN + LATERAL VIEW + MAPJOIN fails to return result (seems to stop halfway through and no longer do the final reduce part)

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.8.1
• Fix Version/s: 0.9.0

Environment

ubuntu - hadoop 0.20.2-cdh3u0 - hive 0.8.1

• Assignee: Unassigned
• Reporter: Ruben de Vries
• Created: 01/May/12 12:52
• Updated: 12/Jul/12 11:23
• Resolved: 10/Jul/12 07:48

Description

Okay first off; I know JOIN + LATERAL VIEW together isn't working so I moved my JOIN into a subquery and that makes the query work properly

However when I added a MAPJOIN hint for the JOIN in the subquery it will also stop doing the reducer for the main query!
This only happens when there's a LATERAL VIEW in there though, if I remove the LATERAL VIEW then the main query still get's a reducer to do grouping

Here's a gist: https://gist.github.com/2499436 Containing the queries and a PHP script which you can run to execute the test case I'm using, which does;

• setup a database called hive_mapjoin
• setup tables
• load some test data
• do the selects
  You'll need the https://github.com/rcongiu/Hive-JSON-Serde/downloads json-serde-1.1-jar-with-dependencies.jar with it though and change the path
  I guess looking at the queries you guys can probally figure out a better testcase, but maybe it's helpful

Not sure if this is a bug or me doing something that just isn't supposed to be working, but I can't seem to find any pointers that this wouldn't be supported...

Here's another gist with the plan.xml: https://gist.github.com/2499658