[IMPALA-2909] Unable to plan right outer join when select is constant NULL

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Affects Version/s: impala 2.3
• Component/s: Frontend
• Labels: planner usability
• Target Version: Product Backlog
• Assignee: Unassigned
• Reporter: Jim Apple
• Created: 29/Jan/16 16:06
• Updated: 19/Aug/16 07:39
• Resolved: 19/Aug/16 07:39

Description

Query: explain select *
from (select null x from alltypessmall) a
right outer join (select id + null y from alltypestiny) b
on (a.x = b.y)
+-----------------------------------------------------------+
| Explain String                                            |
+-----------------------------------------------------------+
| Estimated Per-Host Requirements: Memory=160.00MB VCores=2 |
|                                                           |
| 04:EXCHANGE [UNPARTITIONED]                               |
| |                                                         |
| 02:NESTED LOOP JOIN [LEFT OUTER JOIN, BROADCAST]          |
| |  join predicates: (NULL = id + NULL)                    |
| |                                                         |
| |--03:EXCHANGE [BROADCAST]                                |
| |  |                                                      |
| |  00:SCAN HDFS [functional.alltypessmall]                |
| |     partitions=4/4 files=4 size=6.32KB                  |
| |                                                         |
| 01:SCAN HDFS [functional.alltypestiny]                    |
|    partitions=4/4 files=4 size=460B                       |
+-----------------------------------------------------------+

Query: explain select *
from (select null x from alltypessmall) a
right outer join (select null y from alltypestiny) b
on (a.x = b.y)
ERROR: NotImplementedException: Error generating a valid execution plan for
this query. A RIGHT OUTER JOIN type with no equi-join predicates can only be
executed with a single node plan.

Issue Links

• is related to: IMPALA-3063 NotImplementedException: ... RIGHT OUTER JOIN ... can only be executed with a single node plan