Use of DISTINCT with SET EMITS script causes Internal Server Error

Detail name	Value
Changelog Number	23957
Type	Bug
Status	Resolved
Affected Versions	Exasol 8.9.0
Fix Versions	Exasol 2025.1.9, Exasol 2026.1.0, Exasol 2025.2.1
Resolution Date	2026-02-18

Description

The use of DISTINCT keyword when calling a SET EMITS script resulted in internal server error.

Example:

CREATE SCHEMA test;
OPEN SCHEMA test;

CREATE OR REPLACE TABLE example_table (example_value VARCHAR(10));
INSERT INTO example_table VALUES ('1'), ('1'), ('2'), ('3'), ('3'), ('4');

-- The SET EMITS SCRIPT
--/
CREATE OR REPLACE PYTHON3 SET SCRIPT test.example_script(
  placename VARCHAR(200)
)
EMITS (place VARCHAR(20000), latitude DOUBLE, longitude DOUBLE) AS

def run(ctx):
    while True:
        value = str(ctx.placename) if ctx.placename is not None else "NULL"
        ctx.emit(f"{value} (Unavailable)", None, None)
        if not ctx.next():
            break
/

-- The use of DISTINCT while calling the script
-- Observed: Internal Server Error
-- Expected: 4 rows
SELECT DISTINCT
    test.example_script(example_table.example_value)
FROM
    example_table;

Workaround

Use the query calling the SET EMITS script as a subquery without DISTINCT. Use DISTINCT keyword on the outer query.

SELECT DISTINCT * FROM (SELECT 
    test.example_script(example_table.example_value)
FROM
    example_table);

Fix

The use of DISTINCT with SET EMITS script now works as intended and produces the expected result.