Transaction-Record Lock

Transaction B\"Insert new accounts\"

COMMIT;

START TRANSACTION;SELECT * FROM account;+----+------------+---------+| id | account_id | balance |+----+------------+---------+|  1 |          1 |   800   ||  4 |          2 |  2700   |+----+------------+---------+SELECT * FROM account WHERE account_id = 1 FOR UPDATE;+----+------------+---------+| id | account_id | balance |+----+------------+---------+|  1 |          1 |     800 |+----+------------+---------+COMMIT;

START TRANSACTION;

X lock of account_id 1

Time Line

Transaction A\"Record lock on account_id\"

unlock all

SELECT * FROM account;+----+------------+---------+| id | account_id | balance |+----+------------+---------+|  1 |          1 |     800 ||  4 |          2 |    2700 ||  9 |          3 |    2000 || 12 |          4 |    2000 |+----+------------+---------+

locked