DDL Algorithm <> Copy could break row based replication

./mysql-test-run.pl --mem  rpl_t_s_4 | tee prt

...

main.rpl_t_s_4 'innodb,mix'              [ skipped ]  Not ROW format

include/master-slave.inc

[connection master]

CREATE TABLE t1 (col1 INT, col2 INT, col_c CHAR(20), KEY idx2 (col_c)) ENGINE = InnoDB ;

INSERT INTO t1 (col1, col2, col_c) VALUES ( 1 , 1, '1');

INSERT INTO t1 (col1, col2, col_c) VALUES ( 2 , 2, '2');

INSERT INTO t1 (col1, col2, col_c) VALUES ( 3 , 3, '3');

INSERT INTO t1 (col1, col2, col_c) VALUES ( 4 , 4, '3333333333');

INSERT INTO t1 (col1, col2, col_c) VALUES ( 5 , 5, '3333333333');

UPDATE t1 SET col2 = 453 WHERE col1 IN (5,4);

UPDATE t1 SET col2 = 130 WHERE col1 IN (5,4);

UPDATE t1 SET col2 = 99 WHERE col1 IN (5,4);

UPDATE t1 SET col2 = 202 WHERE col1 IN (5,4);

UPDATE t1 SET col2 = 464 WHERE col1 IN (5,4);

UPDATE t1 SET col2 = 430 WHERE col1 IN (5,4);

INSERT INTO t1 (col1, col2, col_c) VALUES ( 6 , 6, '6');

ALTER TABLE t1 ADD UNIQUE KEY uidx2 ( col1, col_c );

UPDATE t1 SET col2 = 213 WHERE col1 = 5;

main.rpl_t_s_4 'innodb,row'              [ fail ]

...

=== SHOW SLAVE STATUS ===

...

Slave_IO_Running        Yes

Slave_SQL_Running       No

...

Last_Errno      1062

Last_Error      Could not execute Update_rows_v1 event on table test.t1; Duplicate entry '5-3333333333' for key 'uidx2', Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the event's master log master-bin.000001, end_log_pos 4228

Given the fact that using

   ALTER TABLE t1 ADD UNIQUE KEY uidx2 ( col1, col_c ), ALGORITHM = COPY;

   or

   Engine = MyISAM instead of InnoDB

makes the problem disappear I guess its more an InnoDB than a replication bug.

10.3 09bd2138522787a4e0b015695c462903f4a9e728 2019-02-22

10.4 5b4d6595d26aaaf0bf8bb3c9171cf1da96306a7c 2019-02-21