文章目录
1 读写分离原理
为了确保数据库产品的稳定性,很多数据库拥有双机热备功能,也就是,第一台数据库服务器对外提供增删改业务的生产服务器,第二台数据库服务器,主要进行读的操作。
原理:让主数据库(master)处理事务性增删改操作,而从数据库(slave)处理select 查询操作。
2 Mysql 配置主从复制
2.1 创建2个Mysql 数据库服务,并启动两个Mysql服务
2.2 配置Master库的/etc/my.cnf
[mysqld]
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
user=mysql
port=3306
# Master
# 开启日志
log-bin = mysql-bin
# 日志格式按行同步
binlog-format = ROW
# 设置服务id,主从不能一致
server-id = 1
# 设置需要同步的数据库
binlog-do-db = user_db
# 设置忽略系统库同步
binlog-ignore-db = mysql
binlog-ignore-db = information_schema
binlog-ignore-db = performance_schema
binlog-ignore-db = sys
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# character config
character_set_server=utf8mb4
[mysqld_safe]
log-error=/usr/local/mysql/data/mysql.log
pid-file=/usr/local/mysql/data/mysql.pid
# include all files from the config directory
!includedir /etc/my.cnf.d
主要配置
# Master
# 开启日志
log-bin = mysql-bin
# 日志格式按行同步
binlog-format = ROW
# 设置服务id,主从不能一致
server-id = 1
# 设置需要同步的数据库
binlog-do-db = user_db
# 设置忽略系统库同步
binlog-ignore-db = mysql
binlog-ignore-db = information_schema
binlog-ignore-db = performance_schema
binlog-ignore-db = sys
2.3 配置Slave库的/etc/my.cnf
[mysqld]
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
user=mysql
port=3306
# Slave
# 开启日志
log-bin = mysql-bin
# 日志按照行进行数据同步
binlog-format = ROW
# 设置服务id,主从不能一致
server-id = 2
# 设置需要同步的数据库
replicate-do-db=user_db
# 设置忽略系统库
replicate-ignore-db = mysql
replicate-ignore-db = information_schema
replicate-ignore-db = performance_schema
replicate-ignore-db = sys
#replicate-wild-ignore_table = mysql.%
#replicate-wild-ignore_table = information_schema.%
#replicate-wildignore_table = performance_schema.%
#replicate-wild-ignore_table = sys.%
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
#character config
character_set_server=utf8mb4
[mysqld_safe]
log-error=/usr/local/mysql/data/mysql.log
pid-file=/usr/local/mysql/data/mysql.pid
#
# include all files from the config directory
#
!includedir /etc/my.cnf.d
主要配置
# Slave
# 开启日志
log-bin = mysql-bin
# 日志按照行进行数据同步
binlog-format = ROW
# 设置服务id,主从不能一致
server-id = 2
# 设置需要同步的数据库
replicate-do-db=user_db
# 设置忽略系统库
replicate-ignore-db = mysql
replicate-ignore-db = information_schema
replicate-ignore-db = performance_schema
replicate-ignore-db = sys
2.4 Master上创建用于主从复置的账号
mysql -uroot -p123456 -h192.168.124.12
CREATE USER 'sync'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
# 授权主备复制专用账号
GRANT REPLICATION SLAVE ON *.* TO 'sync'@'%';
show grants for sync;
# 刷新权限
flush privileges;
# 确认位点,记录下文件名及位点
show master status;
mysql 数据库中查询user表获取文件名和点位
mysql-bin.0000011 156
2.5 Slave上设置从库向主库同步
首先切换到从库登录
mysql -uroot -p123456 -h192.168.124.11 -P3306
# 先停止同步
stop slave;
# 修改从库指向到主库,使用上一步记录的文件名以及位点
CHANGE MASTER TO
master_host='192.168.124.12',
master_port=3306,
master_user='sync',
master_password='123456',
master_log_file='mysql-bin.000011',
master_log_pos=156;
# 启动同步
start slave;
# 查看slave 的状态
show slave status;
CREATE SCHEMA `testdb` DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci ;
CREATE TABLE `testdb`.`t_user` (
`id` BIGINT NOT NULL,
`name` VARCHAR(45) NOT NULL,
`age` INT NOT NULL,
PRIMARY KEY (`id`))
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8mb4
COLLATE = utf8mb4_unicode_ci;
INSERT INTO `testdb`.`t_user` (`id`, `name`, `age`) VALUES ('1', 'zhangsan', '3');
需要注意的是数据库的字符集编码必须一致
3 ShardingSphere实现读写分离
3.1 配置properties
# sharding-JDBC分片策略(主从复制配置)
# 配置数据源,给数据源命名
spring.shardingsphere.datasource.names=m0,s0
# 配置数据源具体内容,连接池、驱动、地址、用户名和密码
# testdb 主服务器
spring.shardingsphere.datasource.m0.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.m0.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.m0.url=jdbc:mysql://192.168.124.12:3306/testdb?serverTimezone=GMT%2B8
spring.shardingsphere.datasource.m0.username=root
spring.shardingsphere.datasource.m0.password=123456
# 配置数据源具体内容,连接池、驱动、地址、用户名和密码
# testdb 从服务器
spring.shardingsphere.datasource.s0.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.s0.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.s0.url=jdbc:mysql://192.168.124.11:3306/testdb?serverTimezone=GMT%2B8
spring.shardingsphere.datasource.s0.username=root
spring.shardingsphere.datasource.s0.password=123456
# 一个实体类对应两张表,覆盖
spring.main.allow-bean-definition-overriding=true
# 主从库逻辑数据源定义 ds0 为testdb
spring.shardingsphere.sharding.master-slave-rules.ds0.master-data-source-name=m0
spring.shardingsphere.sharding.master-slave-rules.ds0.slave-data-source-names=s0
# t_user 分表策略,固定分配至ds0的t_user真实表
spring.shardingsphere.sharding.tables.t_user.actual-data-nodes=ds$->{0}.t_user
spring.shardingsphere.sharding.tables.t_user.key-generator.column=id
spring.shardingsphere.sharding.tables.t_user.key-generator.type=SNOWFLAKE
# 打印sql输出日志
spring.shardingsphere.props.sql.show=true
3.2 编写po
package com.ccb.sharding.po;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
@TableName("t_user")
public class Student {
@TableId("id")
private Long id;
private String name;
private int age;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
'}';
}
}
3.3 编写mapper
package com.ccb.sharding.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.ccb.sharding.po.Student;
import com.ccb.sharding.po.User;
import org.springframework.stereotype.Repository;
@Repository
public interface StudentMapper extends BaseMapper<Student> {
}
3.4 编写Test
package com.ccb.sharding;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.ccb.sharding.mapper.StudentMapper;
import com.ccb.sharding.po.Student;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest
class ShardingApplicationTests {
@Autowired
StudentMapper studentMapper;
// ================= 测试读写分离 ======================
@Test
public void addStudentMaster() {
Student student = new Student();
student.setName("Lily");
student.setAge(23);
studentMapper.insert(student);
}
@Test
public void getStudentSlave(){
QueryWrapper queryWrapper = new QueryWrapper();
queryWrapper.eq("id",1278468912563892226L);
Student student = studentMapper.selectOne(queryWrapper);
System.out.println(student);
}
}
3.5 TestRest
3.5.1 主库
3.5.2 从库
Result
3.5.3 写入时
3.5.4 读取时
以上可以看到主从都有数据,并且写入时是主库master,读取时是从库slave,实现了目标主从复制、读写分离