C++博客-技术博客-随笔分类-mysqlhttp://www.cppblog.com/chenjunjun/category/20953.htmlc/c++/python/linuxzh-cnSat, 20 Sep 2014 08:52:27 GMTSat, 20 Sep 2014 08:52:27 GMT60Mysql下InnoDB的可重复读级别的事务测试http://www.cppblog.com/chenjunjun/archive/2014/09/16/208330.htmlchenjunjunchenjunjunTue, 16 Sep 2014 09:44:00 GMThttp://www.cppblog.com/chenjunjun/archive/2014/09/16/208330.htmlhttp://www.cppblog.com/chenjunjun/comments/208330.htmlhttp://www.cppblog.com/chenjunjun/archive/2014/09/16/208330.html#Feedback0http://www.cppblog.com/chenjunjun/comments/commentRss/208330.htmlhttp://www.cppblog.com/chenjunjun/services/trackbacks/208330.htmlMysql下InnoDB的可重复读的事务测试

### 背景：

    * mysql版本：Server version: 5.1.71
    * 操作系统：CentOS 6.5 X64
    * 事务隔离级别：不可重复读

### 实验前的准备：

    mysql> use test;
    mysql> create table test_table(id int primary key, name varchar(255)) ENGINE=InnoDB;
    mysql> insert into test_table value(1, 'lily');
    mysql> create table test_table2(id int primary key, name varchar(255)) ENGINE=InnoDB;
    mysql> insert into test_table2 value(1, 'lucy');

### 实验1

问题：事务从什么时候开始？

测试两边同事开启事务，只在终端A中进行update操作，提交完成之后，在终端B中观察

步骤                      终端A                                        终端B
 1        mysql> set autocommit = off;                      mysql> set autocommit = off;
 2        mysql> update test_table set name = 'lucy';
 3        mysql> commit;
 4                                                          mysql> select * from test_table;
                                                            +----+--------+
                                                            | id | name   |
                                                            +----+--------+
                                                            |  1 | lucy   |
                                                            +----+--------+
                                                            1 rows in set (0.00 sec)
 
 

在终端B中直接可以看到终端A所做的修改，说明事务并不是从命令"set autocommit = off"执行时就开始；


还原影响数据：

    mysql> update test_table set name = 'lily';
    mysql> commit;
    
只在终端A中进行更新操作，同时在终端B中对库中的任意一个表进行一个操作，终端A提交之后，观察终端B中的数据；然后在终端B中执行commit之后，再次查看终端A中修改的数据。
 
 步骤                      终端A                                        终端B
 1        mysql> rollback;                                  mysql> rollback;
 2        mysql> update test_table set name = 'lucy';       mysql> select * from test_table2;
 3        mysql> commit;
 4                                                          mysql> select * from test_table;
                                                            +----+--------+
                                                            | id | name   |
                                                            +----+--------+
                                                            |  1 | lily   |
                                                            +----+--------+
                                                            1 row in set (0.00 sec)

                                                            mysql> commit;
                                                            mysql> select * from test_table;
                                                            +----+--------+
                                                            | id | name   |
                                                            +----+--------+
                                                            |  1 | lucy   |
                                                            +----+--------+
                                                            1 row in set (0.00 sec)



这里启动了事务，说明事务是以第一条SQL时开始的

### 实验2

问题：InnoDB在不可重复读隔离级别下，有没有幻读情况

还原影响数据：

    mysql> update test_table set name = 'lily';
    mysql> commit;

 步骤                      终端A                                        终端B
 1        mysql> rollback;                                  mysql> rollback;
 2        mysql> insert into test_table value(2, 'lucy');   mysql> select * from test_table2;
 3        mysql> commit;
 4                                                          mysql> select * from test_table;
                                                            +----+--------+
                                                            | id | name   |
                                                            +----+--------+
                                                            |  1 | lily   |
                                                            +----+--------+
                                                            1 row in set (0.00 sec)
                                                            mysql> rollback;
                                                            mysql> select * from test_table;
                                                            +----+--------+
                                                            | id | name   |
                                                            +----+--------+
                                                            |  1 | lily   |
                                                            |  2 | lucy   |
                                                            +----+--------+
                                                            2 rows in set (0.00 sec)

这里没有存在幻读的情况，说明InnoDB对幻读有处理。

### 实验3

问题：同事开启两个事务A和B，事务A中插入一条记录R，事务B中插入另一条记录R2，R2的主键与记录R相同，如何处理？

还原影响数据：

    mysql> delete from test_table where id = 2;
    mysql> commit;

步骤                      终端A                                        终端B
 1        mysql> rollback;                                  mysql> rollback;
 2        mysql> insert into test_table value(2, 'lucy');   mysql> select * from test_table2;
 3        mysql> commit;
 4                                                          mysql> insert into test_table value(2, 'lucy');
                                                            ERROR 1062 (23000): Duplicate entry '2' for key 'PRIMARY'

这种情况下，会报错。

### 实验4

问题：不同事务更新同一条记录。

步骤                      终端A                                                终端B
 1        mysql> rollback;                                              mysql> rollback;
 2        mysql> update test_table set name = 'lily2' where id = 1;       
 3                                                                      mysql> update test_table set name = 'lily3' where id = 1;
                                                                        ... 卡住 ... 在超过一定时间之后报错：
                                                                        ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction

两个事务在编辑同一条数据时，先编辑的事务会将该记录锁定，或编辑的事务会等待一定时间，如果一定直接内仍然被锁定则报错。

chenjunjun 2014-09-16 17:44 发表评论
]]>centos 6.5 x86-64 下编译安装mysql_connector_c++http://www.cppblog.com/chenjunjun/archive/2014/08/12/207986.htmlchenjunjunchenjunjunTue, 12 Aug 2014 09:01:00 GMThttp://www.cppblog.com/chenjunjun/archive/2014/08/12/207986.htmlhttp://www.cppblog.com/chenjunjun/comments/207986.htmlhttp://www.cppblog.com/chenjunjun/archive/2014/08/12/207986.html#Feedback0http://www.cppblog.com/chenjunjun/comments/commentRss/207986.htmlhttp://www.cppblog.com/chenjunjun/services/trackbacks/207986.html

    [chenjunjun@localhost ~]$ su -
    Password:
    [root@localhost ~]# yum install wget cmake gcc-c++ boost-devel mysql-devel
    [root@localhost ~]# exit
    logout
    [chenjunjun@localhost ~]$

### 编译安装mysql-connector-c++

    [chenjunjun@localhost ~]$ wget http://dev.mysql.com/get/Downloads/Connector-C++/mysql-connector-c++-1.1.4.tar.gz
    [chenjunjun@localhost ~]$ tar zxvf mysql-connector-c++-1.1.4.tar.gz
    [chenjunjun@localhost ~]$ cd mysql-connector-c++-1.1.4
    [chenjunjun@localhost mysql-connector-c++-1.1.4]$ mkdir build
    [chenjunjun@localhost mysql-connector-c++-1.1.4]$ cd  build
    [chenjunjun@localhost build]$ cmake -DCMAKE_INSTALL_PREFIX=/home/chenjunjun/usr/mysql_connect_c++/ -DMYSQL_LIB=/usr/lib64/mysql/libmysqlclient.so ..
    [chenjunjun@localhost build]$ make
    [chenjunjun@localhost build]$ vim cppconn/cmake_install.cmake
             38     "/home/chenjunjun/mysql-connector-c++-1.1.4/cppconn/config.h"
            ==修改为==>
             38     "/home/chenjunjun/mysql-connector-c++-1.1.4/build/cppconn/config.h"
    [chenjunjun@localhost build]$ make install
    [chenjunjun@localhost build]$ cd
    [chenjunjun@localhost ~]$

### 设置

    [chenjunjun@localhost ~]$ echo "export LD_LIBRARY_PATH=~/usr/mysql_connect_c++/lib/" >> ~/.bashrc
    [chenjunjun@localhost ~]$ . ./.bashrc

### 测试

    [chenjunjun@localhost ~]$ vi test.cc

        #include <iostream>
        #include <string>
        #include <mysql_connection.h>
        #include <mysql_driver.h>
    
        using namespace std;
        using namespace sql;
    
        int main(){
            Driver* driver;
            Connection* conn;
            driver = get_driver_instance();
            conn = driver->connect("数据库地址", "用户名", "用户密码");
            conn->setAutoCommit(1);
            cout << "DataBase connection autocommit mode = " << conn->getAutoCommit() << endl;
            delete conn;
            driver = NULL;
            conn = NULL;
    
            return 0;
        }
    
    [chenjunjun@localhost ~]$ g++ test.cc -I ~/usr/mysql_connect_c++/include -L ~/usr/mysql_connect_c++/lib -l mysqlcppconn -o test
    [chenjunjun@localhost ~]$ ./test
    DataBase connection autocommit mode = 1
    [chenjunjun@localhost ~]$


chenjunjun 2014-08-12 17:01 发表评论
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