connection node_2; connection node_1; CREATE TABLE t1 (f1 BIT) ENGINE=InnoDB; INSERT INTO t1 VALUES (NULL),(0),(b'1'); connection node_2; SELECT f1 IS NULL, f1 = b'1' FROM t1; f1 IS NULL f1 = b'1' 1 NULL 0 0 0 1 DELETE FROM t1 WHERE f1 = b'1'; UPDATE t1 SET f1 = b'1' WHERE f1 IS NULL; UPDATE t1 SET f1 = 1 WHERE f1 = b'0'; connection node_1; SELECT f1 IS NULL, f1 = b'1' FROM t1; f1 IS NULL f1 = b'1' 0 1 0 1 connection node_1; CREATE TABLE t2 (f1 BIT) ENGINE=InnoDB; INSERT INTO t2 VALUES (NULL); SET AUTOCOMMIT=OFF; START TRANSACTION; UPDATE t2 SET f1 = 0 WHERE f1 IS NULL; connection node_2; SET AUTOCOMMIT=OFF; START TRANSACTION; UPDATE t2 SET f1 = 1 WHERE f1 IS NULL; connection node_1; COMMIT; connection node_2; COMMIT; ERROR 40001: Deadlock found when trying to get lock; try restarting transaction DROP TABLE t1; DROP TABLE t2;