CREATE TABLE t (pk int PRIMARY KEY, c varchar(10))
STATS_PERSISTENT=0 ENGINE=InnoDB;
INSERT INTO t VALUES (10, "0123456789");
connection default;
BEGIN;
SELECT * FROM t WHERE c = 10 FOR UPDATE;
pk	c
connect trx2, localhost,root,,;
BEGIN;
SET DEBUG_SYNC="lock_wait_start SIGNAL trx2_start_waiting";
SET DEBUG_SYNC="lock_wait_end SIGNAL trx2_wait_end WAIT_FOR trx2_cont_upd";
SET DEBUG_SYNC="lock_rec_store_on_page_infimum_end SIGNAL trx2_moved_locks WAIT_FOR trx2_cont";
UPDATE t SET c = NULL WHERE pk = 10;
connect trx3, localhost,root,,;
SET DEBUG_SYNC="now WAIT_FOR trx2_start_waiting";
SET innodb_lock_wait_timeout=1;
BEGIN;
SET DEBUG_SYNC="lock_wait_start SIGNAL trx3_start_waiting WAIT_FOR trx3_cont_waiting";
SET DEBUG_SYNC="lock_sys_t_cancel_enter SIGNAL trx3_cancel_enter WAIT_FOR trx3_cont_cancel_waiting";
UPDATE t SET c = "abcdefghij" WHERE pk = 10;
connection default;
SET DEBUG_SYNC="now WAIT_FOR trx3_start_waiting";
COMMIT;
SET DEBUG_SYNC="now WAIT_FOR trx2_wait_end";
SET DEBUG_SYNC="now SIGNAL trx3_cont_waiting";
SET DEBUG_SYNC="now WAIT_FOR trx3_cancel_enter";
SET DEBUG_SYNC="now SIGNAL trx2_cont_upd";
SET DEBUG_SYNC="now WAIT_FOR trx2_moved_locks";
SET DEBUG_SYNC="now SIGNAL trx3_cont_cancel_waiting";
SET DEBUG_SYNC="now SIGNAL trx2_cont";
disconnect trx2;
disconnect trx3;
connection default;
SET DEBUG_SYNC="RESET";
DROP TABLE t;