[IMPALA-852] Aggregate and predicate ignored on very simple query without group by clause or aggergate expressions in select clause

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 1.3, Impala 2.0, Impala 2.2, Impala 2.3.0
• Fix Version/s: Impala 2.5.0
• Component/s: Frontend
• Labels: correctness downgraded ramp-up
• Target Version: Product Backlog
• Assignee: Alexander Behm
• Reporter: casey
• Created: 05/Mar/14 22:45
• Updated: 04/Jan/17 23:58
• Resolved: 06/Feb/16 01:35

Description

MySQL and Postgresql agree that the result of

SELECT 1 FROM non_empty_table HAVING COUNT > 0

should be a single row with the value 1. However impala returns a 1 for each row in the table.

The explain plan shows the aggregate and predicate are not considered.

[localhost:21000] > explain select 1 from tinytable having count(*) > 0;
Query: explain select 1 from tinytable having count(*) > 0
+----------------------------------------------------------+
| Explain String                                           |
+----------------------------------------------------------+
| Estimated Per-Host Requirements: Memory=32.00MB VCores=1 |
|                                                          |
| 01:EXCHANGE [PARTITION=UNPARTITIONED]                    |
| |                                                        |
| 00:SCAN HDFS [functional.tinytable]                      |
|    partitions=1/1 size=76B                               |
+----------------------------------------------------------+
Returned 6 row(s) in 0.02s


mysql> select 1 from table_1 having count(*) > 0;
+---+
| 1 |
+---+
| 1 |
+---+
1 row in set (0.00 sec)


randomness=# select 1 from table_1 having count(*) > 0;
 ?column? 
----------
        1
(1 row)