[DRILL-6291] Wrong result for COUNT function and empty file (schemaless table)

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.13.0
• Fix Version/s: Future
• Component/s: Functions - Drill
• Assignee: Hanumath Rao Maduri
• Reporter: Vitalii Diravka
• Created: 23/Mar/18 16:26
• Updated: 24/Mar/18 15:36

Description

The count function shouldn't return null result. For the 0 rows case it should always return 0.

0: jdbc:drill:zk=local> select count(`last_name`) from dfs.`/tmp/empty_file.json`;
+---------+
| EXPR$0  |
+---------+
+---------+
No rows selected (0.3 seconds)

The result should be the similar to:

0: jdbc:drill:zk=local> select count(`non_existent_column`) from cp.`employee.json`;
+---------+
| EXPR$0  |
+---------+
| 0       |
+---------+
1 row selected (0.274 seconds)

Note: empty_file.json is an empty file.