Comparing a CHAR ASCII column with an UTF8 filter might cause an error

Details

Detail name Value
Changelog Number 31778
Type Bug
Status Resolved
Affected Versions EXASOL 6.0.0, Exasol 6.2.0, Exasol 7.0.0, Exasol 7.1.0, Exasol 8.0.0, Exasol 8.29.0, Exasol 2025.1.0, Exasol 2026.1.0
Fix Versions Exasol 2025.1.14, Exasol 2026.1.2
Resolution Date 2026-08-06

Description

Under very rare circumstances, a query that filters a CHAR ASCII column might cause an Internal Server Error.
Note that this error does not occur often even for the same query.
Conditions:

  • The filter is on a CHAR ASCII column.
  • The filter contains UTF8 characters.

Example: 

CREATE TABLE t(a CHAR(12) ASCII);
INSERT INTO t values 'a';

SELECT * FROM t WHERE a = 'ÄÄÄÄÄ';

Workaround

Execute the query a second time.

Fix

The query returns empty results.