MySQL在备份方面包含了自身的mysqldump工具，但其只支持单线程工作，这就使得它无法迅速的备份数据。而mydumper作为一个实用工具，能够良好支持多线程工作，这使得它在处理速度方面十倍于传统的mysqldump。其特征之一是在处理过程中需要对列表加以锁定，因此如果我们需要在工作时段执行备份工作，那么会引起DML阻塞。但一般现在的MySQL都有主从，备份也大部分在从上进行，所以锁的问题可以不用考虑。这样，mydumper能更好的完成备份任务。mydumper具备以下特点：
- 轻量级C语言写的
- 执行速度比mysqldump快10倍
- 事务性和非事务性表一致的快照(适用于0.2.2以上版本)
- 快速的文件压缩
- 支持导出binlog
- 多线程恢复(适用于0.2.1以上版本)
- 以守护进程的工作方式，定时快照和连续二进制日志(适用于0.5.0以上版本)
- 开源组件(GNU GPLv3)
视频讲解如下：
下面通过具体的步骤来演示如何使用mydumper进行数据库的热备份与恢复。
（1）安装mydumper
yum install -y \ https://github.com/maxbube/mydumper/releases/download/v0.9.5/mydumper-0.9.5-2.el7.x86_64.rpm
（2）查看mydumper的帮助信息
mydumper --help # 输出的信息如下： Usage: mydumper [OPTION...] multi-threaded MySQL dumping Help Options: -?, --help Show help options Application Options: -B, --database Database to dump -T, --tables-list Comma delimited table list to dump (does not exclude regex option) -O, --omit-from-file File containing a list of database.table entries to skip, one per line (skips before applying regex option) -o, --outputdir Directory to output files to ......
下表是mydumper常用参数的说明。
（3）创建mydumper备份的存储目录。
mkdir -p /databackup/mydumper/all/
（4）备份所有数据库
mydumper -u root --password=Welcome_1 \ --socket /tmp/mysql.sock \ --outputdir /databackup/mydumper/all/ # 提示：这里的--socket /tmp/mysql.sock参数是必须的。在默认情况下mydumper在加载/var/lib/mysql/mysql.sock文件。如果该文件不存在，将出现下面的错误信息。 ** (mydumper:69463): CRITICAL **: Error connecting to database: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock'
（5）查看目录/databackup/mydumper/下的内容
tree /databackup/mydumper/all | more # 输出的信息如下： /databackup/mydumper/all ├── demo1.audit_message-schema.sql ├── demo1.audit_message.sql ├── demo1.classes-schema.sql ├── demo1.dept-schema.sql ├── demo1.dept.sql ├── demo1.emp-schema.sql ├── demo1.emp.sql ├── demo1.indextable1-schema.sql ├── demo1.indextable1.sql ......
（6）查看文件/databackup/mydumper/demo1.emp.sql的内容
cat /databackup/mydumper/demo1.emp.sql # 输出的信息如下： /*!40101 SET NAMES binary*/; /*!40014 SET FOREIGN_KEY_CHECKS=0*/; /*!40103 SET TIME_ZONE='+00:00' */; INSERT INTO `emp` VALUES (7369,"SMITH","CLERK",7902,"1980/12/17",800,NULL,20), (7499,"ALLEN","SALESMAN",7698,"1981/2/20",1600,300,30), (7521,"WARD","SALESMAN",7698,"1981/2/22",1250,500,30), (7566,"JONES","MANAGER",7839,"1981/4/2",3670,NULL,20), (7654,"MARTIN","SALESMAN",7698,"1981/9/28",1250,1400,30), (7698,"BLAKE","MANAGER",7839,"1981/5/1",2850,NULL,30), (7782,"CLARK","MANAGER",7839,"1981/6/9",2550,NULL,10), (7788,"SCOTT","ANALYST",7566,"1987/4/19",3000,NULL,20), (7839,"KING","PRESIDENT",-1,"1981/11/17",5950,NULL,10), (7844,"TURNER","SALESMAN",7698,"1981/9/8",1500,NULL,30), (7876,"ADAMS","CLERK",7788,"1987/5/23",1100,NULL,20), (7900,"JAMES","CLERK",7698,"1981/12/3",950,NULL,30), (7902,"FORD","ANALYST",7566,"1981/12/3",3000,NULL,20), (7934,"MILLER","CLERK",7782,"1982/1/23",1400,NULL,10); # 提示：可以看出mydump也将数据备份成了SQL语句。
（7）备份指定数据库demo1
mkdir -p /databackup/mydumper/demo1/ mydumper -u root --password=Welcome_1 \ --socket /tmp/mysql.sock \ --database demo1 \ --outputdir /databackup/mydumper/demo1/
（8）备份指定数据库demo1下指定的表（员工表和部门表）
mkdir -p /databackup/mydumper/multi_tables/ mydumper -u root --password=Welcome_1 \ --socket /tmp/mysql.sock \ --database demo1 \ --tables-list emp,dept \ --outputdir /databackup/mydumper/multi_tables/
（9）删除demo1数据库
mysqladmin -uroot -pWelcome_1 drop demo1 # 输出的信息如下： Dropping the database is potentially a very bad thing to do. Any data stored in the database will be destroyed. Do you really want to drop the 'demo1' database [y/N] y Database "demo1" dropped
（10）使用myloader执行恢复数据库demo1
mysqladmin -uroot -pWelcome_1 create demo1 myloader -u root -p Welcome_1 --socket /tmp/mysql.sock \ --database demo1 \ -d /databackup/mydumper/demo1/ # 提示：在执行恢复之前，demo1如果没有，则需要事先创建。
（11）检查数据是否恢复
