[MDEV-8636] Different warnings with and without index on WHERE varchar_column='bad_byte_sequence' Created: 2015-08-17  Updated: 2015-10-28

Status: Open
Project: MariaDB Server
Component/s: Character Sets
Affects Version/s: 5.5, 10.0, 10.1
Fix Version/s: 10.1

Type: Bug Priority: Minor
Reporter: Alexander Barkov Assignee: Alexander Barkov
Resolution: Unresolved Votes: 0
Labels: None


 Description   

If I run this script with a bad byte sequence (notice '��' is a valid 4-byte utf8mb4 character, but it's not a valid for 3-byte utf8):

SET NAMES utf8;
 
DROP TABLE IF EXISTS t1;
 
CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET utf8, KEY(a)) ENGINE=MyISAM;
 
INSERT INTO t1 VALUES ('a'),('b'),('c'),('d'),('e');
 
SELECT * FROM t1 WHERE a='��';
 
SHOW WARNINGS;

it returns empty set with a warning:

+---------+------+--------------------------------------------------------------------+
 
| Level   | Code | Message                                                            |
 
+---------+------+--------------------------------------------------------------------+
 
| Warning | 1366 | Incorrect string value: '\xF0\x9F\x98\x8E' for column 'a' at row 1 |
 
+---------+------+--------------------------------------------------------------------+

Now if I drop the index and re-run the SELECT query:

ALTER TABLE t1 DROP KEY a;
 
SELECT * FROM t1 WHERE a='��';
 
SHOW WARNINGS;

it still returns empty set but without any warning.

It should be fixed to produce the same warnings with and without indexes.
Preferably, one warning in both cases.
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