Transaction2

UPDATE account SET balance = 2700 WHERE account_id = 2;

UPDATE accountSET balance = 2000WHERE account_id = 2;

SELECT * FROM account;+----+------------+---------+| id | account_id | balance |+----+------------+---------+|  1 |          1 |    1500 ||  4 |          2 |    2000 |+----+------------+---------+

Time Line

Transaction A\"Transfer 200 from 1 to 2\"

locked

UPDATE account SET balance = 2700 WHERE account_id = 2;ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction

SELECT * FROM account;+----+------------+---------+| id | account_id | balance |+----+------------+---------+|  1 |          1 |  1000   ||  4 |          2 |  2500   |+----+------------+---------+

blocking

lock account_id 2

UPDATE accountSET balance = 800WHERE account_id = 1;

lock account_id 1

Transaction B\"Transfer 500 from 2 to 1\"

START TRANSACTION;

SELECT * FROM account;+----+------------+---------+| id | account_id | balance |+----+------------+---------+|  1 |          1 |    800 ||  4 |          2 |    2700 |+----+------------+---------+

COMMIT;

unlock all

UPDATE accountSET balance = 1500WHERE account_id = 1;

deadlock solved