Read Committed
在Read Committed隔离级别下,一个事务可能会遇到不可重复读(Non Repeatable Read)的问题。
不可重复读是指,在一个事务内,多次读同一数据,在这个事务还没有结束时,如果另一个事务恰好修改了这个数据,那么,在第一个事务中,两次读取的数据就可能不一致。直线电机哪家好
我们仍然先准备好students
表的数据:
mysql> select * from students;
+----+-------+
| id | name |
+----+-------+
| 1 | Alice |
+----+-------+
1 row in set (0.00 sec)
然后,分别开启两个MySQL客户端连接,按顺序依次执行事务A和事务B:
时刻 | 事务A | 事务B |
---|---|---|
1 | SET TRANSACTION ISOLATION LEVEL READ COMMITTED; | SET TRANSACTION ISOLATION LEVEL READ COMMITTED; |
2 | BEGIN; | BEGIN; |
3 | SELECT * FROM students WHERE id = 1; | |
4 | UPDATE students SET name = 'Bob' WHERE id = 1; | |
5 | COMMIT; | |
6 | SELECT * FROM students WHERE id = 1; | |
7 | COMMIT; |
Read Committed的更多相关文章
- Cannot forward after response has been committed
项目:蒙文词语检索 日期:2016-05-01 提示:Cannot forward after response has been committed 出处:request.getRequestDis ...
- which type of VS files should be committed into a version control system
which type of VS files should be committed into a version control system? aps, no: last resource edi ...
- when will a databasechange be committed?
1) Database-updates via DML in a SQLExec-statement (e.g. INSERT INTO PS_TEST_TABLE VALUES(‘value_fie ...
- 报错:java.lang.IllegalStateException: Cannot call sendError() after the response has been committed(待解答)
严重: Servlet.service() for servlet [default] in context with path [/20161101-struts2-1] threw excepti ...
- grails中报Cannot create a session after the response has been committed异常的解决办法
在grails中,我们在layouts\main.gsp中使用类似如下的代码来判断当前用户处于登录状态时显示相关的登录信息: <g:if test="${session.users}& ...
- java.lang.IllegalStateException: Cannot call sendError() after the response has been committed
http://blog.csdn.net/chenghui0317/article/details/9531171 —————————————————————————————————————————— ...
- Cannot call sendRedirect() after the response has been committed
AJAX+JSP时,out.write('content')之后,如果后面还有代码,无法被执行到,会报 错,java.lang.IllegalStateException: Cannot call s ...
- Cannot call sendError() after the response has been committed - baiyangliu - 博客频道 - CSDN.NET
body{ font-family: "Microsoft YaHei UI","Microsoft YaHei",SimSun,"Segoe UI& ...
- 【眼见为实】自己动手实践理解READ COMMITTED && MVCC
[眼见为实]自己动手实践理解 READ COMMITTED && MVCC 首先设置数据库隔离级别为读已提交(READ COMMITTED): set global transacti ...
- java.lang.IllegalStateException: Cannot forward after response has been committed的一个情况解决方法
java.lang.IllegalStateException: Cannot forward after response has been committed xxx.xxx.doPost(upd ...
随机推荐
- Spring讲解(三)
依赖注入Bean属性,使用xml配置 1.构造方法注入 案例代码演示 public class User { private String username; private String passw ...
- Math.random()详解
Math.random()是令系统随机选取大于等于 0.0 且小于 1.0 的伪随机 double 值,是Java语言常用代码.例如:double a=Math.random()*(3-1)+1,设置 ...
- 【leetcode】926.Flip String to Monotone Increasing
题目如下: A string of '0's and '1's is monotone increasing if it consists of some number of '0's (possib ...
- bootsrap 按钮样式
<!-- Standard button --> <button type="button" class="btn btn-default"& ...
- layout -panel01
<script src="~/jquery-easyui-1.5.5.2/jquery.min.js"></script> <link href=&q ...
- boost库:事件处理
boost库的signal所实现的模式被命名为信号至插槽,当对应的信号被发出时,相关联的插槽即被执行. #include <boost/signal.hpp> #include <i ...
- PIC16F877A的TIME0学习
计算溢出时间根据晶振频率4Mhz,TMR0=6,PSA2~PSA0 = 1:4. 因为好像外部晶振在给PIC的时候多分了一次1:4.所以PSA2~PSA0取1:4刚好 数完250次的时间=(1/4Mh ...
- hdu 3572 Task Schedule (Dinic模板)
Problem Description Our geometry princess XMM has stoped her study in computational geometry to conc ...
- [NOIP模拟测试34]反思+题解
不要陷入思维定势,如果长时间没有突破就要考虑更改大方向. 不要把简单问题复杂化. 做完的题就先放下,不管能拿多少分.不能过一段时间就回来调一下. $Solutions:$ A.次芝麻 因为$n+m$始 ...
- 项目质量管理—七种基本质量工具
出处:PMBOK(第五版) P236 1.因果图,又称鱼骨图或石川图 用来追溯问题来源,回推到可行动的根本原因.(找根本原因) 2.流程图,也称过程图 用来显示在一个或多个输入转化成一个或多个输出的过 ...