如何实现MySQL底层优化：事务的并发控制和隔离级别选择

START TRANSACTION;  -- 开启事务

-- 对数据表加锁
LOCK TABLES table1 WRITE, table2 READ;

-- 执行具体的读写操作，如：
SELECT * FROM table1 WHERE id = 1;
UPDATE table1 SET column1 = 'value1' WHERE id = 1;

-- 释放锁定
UNLOCK TABLES;

COMMIT; -- 提交事务

SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;  -- 设置事务隔离级别为READ COMMITTED

START TRANSACTION;  -- 开启事务

-- 执行具体的读写操作，如：
SELECT * FROM table1 WHERE id = 1;
UPDATE table1 SET column1 = 'value1' WHERE id = 1;

COMMIT; -- 提交事务

SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;  -- 设置事务隔离级别为READ COMMITTED

START TRANSACTION;  -- 开启事务

-- 执行具体的读写操作，如：
SELECT * FROM table1 WHERE id = 1;
UPDATE table1 SET column1 = 'value1' WHERE id = 1;

COMMIT; -- 提交事务

SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;

START TRANSACTION;

-- 执行具体的读写操作

COMMIT;

SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;

START TRANSACTION;

-- 执行具体的读写操作

COMMIT;

SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ;

START TRANSACTION;

-- 执行具体的读写操作

COMMIT;

SET SESSION TRANSACTION ISOLATION LEVEL SERIALIZABLE;

START TRANSACTION;

-- 执行具体的读写操作

COMMIT;