[ASTERIXDB-2782] Left outer nested loop join gives incorrect result on empty input

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.9.4
• Fix Version/s: 0.9.5
• Component/s: RT - Runtime
• Assignee: Ali Alsuliman
• Reporter: Ali Alsuliman
• Created: 24/Sep/20 00:23
• Updated: 06/Nov/20 17:44
• Resolved: 06/Nov/20 17:44

Description

The below query which uses hash-join returns the expected result 

// ds1 has one tuple {"id": "1", "f": 3}
// ds2 is an empty dataset
FROM ds1 LEFT OUTER JOIN ds2 ON ds1.f = ds2.f
SELECT ds1, ds2;

The returned result is

{ "ds1": { "id": "1", "f": 3 } }

But the below equivalent query which uses nested-loop join returns incorrect result

FROM ds1 LEFT OUTER JOIN ds2 ON ds1.f > ds2.f
SELECT ds1, ds2;

The returned result is

{ }