事务隔离级别演示

事务隔离级别演示

​ 1.read uncommitted：读未提交

演示：

​ set global transaction isolation level read uncommitted；
​ start transaction;
​ - - 转账操作
​ update account set balance = balance - 500 where id = 1;
​ update account set balance = balance +500 where id = 2;

事务一：

 

 事务二：

 

 

 

​ 2.read committed：读已提交（Oracle)

 set global transaction isolation level read committed；

start transaction;

- - 转账操作
​update account set balance = balance - 500 where id = 1;
update account set balance = balance +500 where id = 2;

事务一：

 

 事务二：

 

 

​ 3.repeatable read：可重复读（MYSQL默认)

set global transaction isolation level repeatable read；

start transaction;

- - 转账操作
​update account set balance = balance - 500 where id = 1;
update account set balance = balance +500 where id = 2;

事务一：

 

 事务二：

 

 

 

​ 4.serializable：串行化

set global transaction isolation level serializable;

start transaction;

- - 转账操作
​update account set balance = balance - 500 where id = 1;
update account set balance = balance +500 where id = 2;

事务一：

 

 事务二：