目录

一、目标二、环境准备1、基本信息2、数据库环境准备3、建库 & 导入分表三、配置&实践1、pom文件  
2、常量配置3、yml 配置4、分库分表策略5、dao层编写6、单元测试四、总结

一、目标

本文将完成如下目标:

分表数量: 256    分库数量: 4 以用户ID(user_id) 为数据库分片Key 最后测试订单创建，更新，删除, 单订单号查询，根据user_id查询列表操作。

架构图:

表结构如下:

CREATE TABLE `order_XXX` (
  `order_id` bigint(20) unsigned NOT NULL,
  `user_id` int(11) DEFAULT '0' COMMENT '订单id',
  `status` int(11) DEFAULT '0' COMMENT '订单状态',
  `booking_date` datetime DEFAULT NULL,
  `create_time` datetime DEFAULT NULL,
  `update_time` datetime DEFAULT NULL,
  PRIMARY KEY (`order_id`),
  KEY `idx_user_id` (`user_id`),
  KEY `idx_bdate` (`booking_date`),
  KEY `idx_ctime` (`create_time`),
  KEY `idx_utime` (`update_time`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

注:  000<= XXX <= 255, 本文重点在于分库分表实践, 只保留具有代表性字段，其它场景可以在此基础上做改进。

全局唯一ID设计

要求:1.全局唯一 2:粗略有序 3:可反解出库编号

1bit + 39bit时间差 + 8bit机器号 + 8bit用户编号(库号) + 8bit自增序列

单机最大QPS: 256000 使用寿命: 17年

二、环境准备

1、基本信息

2、数据库环境准备

进入mysql:

#主库
 mysql -h 172.30.1.21 -uroot -pbytearch

#从库
 mysql -h 172.30.1.31 -uroot -pbytearch

进入容器

#主
docker exec -it db_1_master /bin/bash

#从
docker exec -it db_1_slave /bin/bash

查看运行状态

#主
docker exec db_1_master sh -c 'mysql -u root -pbytearch -e "SHOW MASTER STATUS \G"'
#从
docker exec db_1_slave sh -c 'mysql -u root -pbytearch -e "SHOW SLAVE STATUS \G"'

3、建库 & 导入分表

（1）在mysql master实例分别建库

172.30.1.21(   o rder_db_ 1) ,  172.30.1.22( order_db_2) ,

172.30.1.23( ord er_db_3) ,   172.30.1.24( order_db_4 )

（2）依次导入建表SQL 命令为

mysql -uroot -pbytearch -h172.30.1.21 order_db_1<fast-cloud-mysql-sharding/doc/sql/order_db_1.sql;
mysql -uroot -pbytearch -h172.30.1.22 order_db_2<fast-cloud-mysql-sharding/doc/sql/order_db_2.sql;
mysql -uroot -pbytearch -h172.30.1.23 order_db_3<fast-cloud-mysql-sharding/doc/sql/order_db_3.sql;
mysql -uroot -pbytearch -h172.30.1.24 order_db_4<fast-cloud-mysql-sharding/doc/sql/order_db_4.sql;

三、配置&实践

1、pom文件  

     <!-- mango 分库分表中间件 --> 
            <dependency>
                <groupId>org.jfaster</groupId>
                <artifactId>mango-spring-boot-starter</artifactId>
                <version>2.0.1</version>
            </dependency>
         
             <!-- 分布式ID生成器 -->
            <dependency>
                <groupId>com.bytearch</groupId>
                <artifactId>fast-cloud-id-generator</artifactId>
                <version>${version}</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>6.0.6</version>
            </dependency>

2、常量配置

package com.bytearch.fast.cloud.mysql.sharding.common;

/**
 * 分库分表策略常用常量
 */
public class ShardingStrategyConstant {
    /**
     * database 逻辑名称 ，真实库名为 order_db_XXX
     */
    public static final String LOGIC_ORDER_DATABASE_NAME = "order_db";
    /**
     * 分表数 256，一旦确定不可更改
     */
    public static final int SHARDING_TABLE_NUM = 256;

    /**
     * 分库数, 不建议更改， 可以更改，但是需要DBA迁移数据
     */
    public static final int SHARDING_DATABASE_NODE_NUM = 4;
}

3、yml 配置

4主4从数据库配置， 这里仅测试默认使用root用户密码，生产环境不建议使用root用户。

mango:
  scan-package: com.bytearch.fast.cloud.mysql.sharding.dao
  datasources:
    - name: order_db_1
      master:
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://172.30.1.21:3306/order_db_1?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedState&connectTimeout=1000&socketTimeout=5000&useSSL=false
        user-name: root
        password: bytearch
        maximum-pool-size: 10
        connection-timeout: 3000
      slaves:
        - driver-class-name: com.mysql.cj.jdbc.Driver
          jdbc-url: jdbc:mysql://172.30.1.31:3306/order_db_1?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedState&connectTimeout=1000&socketTimeout=5000&useSSL=false
          user-name: root
          password: bytearch
          maximum-pool-size: 10
          connection-timeout: 3000
    - name: order_db_2
      master:
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://172.30.1.22:3306/order_db_2?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedState&connectTimeout=1000&socketTimeout=5000&useSSL=false
        user-name: root
        password: bytearch
        maximum-pool-size: 10
        connection-timeout: 3000
      slaves:
        - driver-class-name: com.mysql.cj.jdbc.Driver
          jdbc-url: jdbc:mysql://172.30.1.32:3306/order_db_2?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedState&connectTimeout=1000&socketTimeout=5000&useSSL=false
          user-name: root
          password: bytearch
          maximum-pool-size: 10
          connection-timeout: 3000
    - name: order_db_3
      master:
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://172.30.1.23:3306/order_db_3?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedState&connectTimeout=1000&socketTimeout=5000&useSSL=false
        user-name: root
        password: bytearch
        maximum-pool-size: 10
        connection-timeout: 3000
      slaves:
        - driver-class-name: com.mysql.cj.jdbc.Driver
          jdbc-url: jdbc:mysql://172.30.1.33:3306/order_db_3?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedState&connectTimeout=1000&socketTimeout=5000&useSSL=false
          user-name: root
          password: bytearch
          maximum-pool-size: 10
          connection-timeout: 3000
    - name: order_db_4
      master:
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://172.30.1.24:3306/order_db_4?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedState&connectTimeout=1000&socketTimeout=5000&useSSL=false
        user-name: root
        password: bytearch
        maximum-pool-size: 10
        connection-timeout: 3000
      slaves:
        - driver-class-name: com.mysql.cj.jdbc.Driver
          jdbc-url: jdbc:mysql://172.30.1.34:3306/order_db_4?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedState&connectTimeout=1000&socketTimeout=5000&useSSL=false
          user-name: root
          password: bytearch
          maximum-pool-size: 10
          connection-timeout: 300

4、分库分表策略

1). 根据order_id为shardKey分库分表策略

package com.bytearch.fast.cloud.mysql.sharding.strategy;

import com.bytearch.fast.cloud.mysql.sharding.common.ShardingStrategyConstant;
import com.bytearch.id.generator.IdEntity;
import com.bytearch.id.generator.SeqIdUtil;
import org.jfaster.mango.sharding.ShardingStrategy;

/**
 * 订单号分库分表策略
 */
public class OrderIdShardingStrategy implements ShardingStrategy<Long, Long> {
    @Override
    public String getDataSourceFactoryName(Long orderId) {
        if (orderId == null || orderId < 0L) {
            throw new IllegalArgumentException("order_id is invalid!");
        }
        IdEntity idEntity = SeqIdUtil.decodeId(orderId);
        if (idEntity.getExtraId() >= ShardingStrategyConstant.SHARDING_TABLE_NUM) {
            throw new IllegalArgumentException("sharding table Num is invalid, tableNum:" + idEntity.getExtraId());
        }
        //1. 计算步长
        int step = ShardingStrategyConstant.SHARDING_TABLE_NUM / ShardingStrategyConstant.SHARDING_DATABASE_NODE_NUM;
        //2. 计算出库编号
        long dbNo = Math.floorDiv(idEntity.getExtraId(), step) + 1;
        //3. 返回数据源名
        return String.format("%s_%s", ShardingStrategyConstant.LOGIC_ORDER_DATABASE_NAME, dbNo);
    }

    @Override
    public String getTargetTable(String logicTableName, Long orderId) {
        if (orderId == null || orderId < 0L) {
            throw new IllegalArgumentException("order_id is invalid!");
        }
        IdEntity idEntity = SeqIdUtil.decodeId(orderId);
        if (idEntity.getExtraId() >= ShardingStrategyConstant.SHARDING_TABLE_NUM) {
            throw new IllegalArgumentException("sharding table Num is invalid, tableNum:" + idEntity.getExtraId());
        }
        // 基于约定，真实表名为 logicTableName_XXX， XXX不足三位补0
        return String.format("%s_%03d", logicTableName, idEntity.getExtraId());
    }
}

2). 根据user_id 为shardKey分库分表策略

package com.bytearch.fast.cloud.mysql.sharding.strategy;

import com.bytearch.fast.cloud.mysql.sharding.common.ShardingStrategyConstant;
import org.jfaster.mango.sharding.ShardingStrategy;

/**
 * 指定分片KEY 分库分表策略
 */
public class UserIdShardingStrategy implements ShardingStrategy<Integer, Integer> {

    @Override
    public String getDataSourceFactoryName(Integer userId) {
        //1. 计算步长 即单库放得表数量
        int step = ShardingStrategyConstant.SHARDING_TABLE_NUM / ShardingStrategyConstant.SHARDING_DATABASE_NODE_NUM;
        //2. 计算出库编号
        long dbNo = Math.floorDiv(userId % ShardingStrategyConstant.SHARDING_TABLE_NUM, step) + 1;
        //3. 返回数据源名
        return String.format("%s_%s", ShardingStrategyConstant.LOGIC_ORDER_DATABASE_NAME, dbNo);
    }

    @Override
    public String getTargetTable(String logicTableName, Integer userId) {
        // 基于约定，真实表名为 logicTableName_XXX， XXX不足三位补0
        return String.format("%s_%03d", logicTableName, userId % ShardingStrategyConstant.SHARDING_TABLE_NUM);
    }
}

5、dao层编写

1). OrderPartitionByIdDao

package com.bytearch.fast.cloud.mysql.sharding.dao;

import com.bytearch.fast.cloud.mysql.sharding.common.ShardingStrategyConstant;
import com.bytearch.fast.cloud.mysql.sharding.pojo.entity.OrderEntity;
import com.bytearch.fast.cloud.mysql.sharding.strategy.OrderIdShardingStrategy;
import org.jfaster.mango.annotation.*;

@DB(name = ShardingStrategyConstant.LOGIC_ORDER_DATABASE_NAME, table = "order")
@Sharding(shardingStrategy = OrderIdShardingStrategy.class)
public interface OrderPartitionByIdDao {

    @SQL("INSERT INTO #table (order_id, user_id, status, booking_date, create_time, update_time) VALUES" +
            "(:orderId,:userId,:status,:bookingDate,:createTime,:updateTime)"
    )
    int insertOrder(@TableShardingBy("orderId") @DatabaseShardingBy("orderId") OrderEntity orderEntity);

    @SQL("UPDATE #table set update_time = now()" +
            "#if(:bookingDate != null),booking_date = :bookingDate #end " +
            "#if (:status != null), status = :status #end" +
            "WHERE order_id = :orderId"
    )
    int updateOrderByOrderId(@TableShardingBy("orderId") @DatabaseShardingBy("orderId") OrderEntity orderEntity);


    @SQL("SELECT * FROM #table WHERE order_id = :1")
    OrderEntity getOrderById(@TableShardingBy @DatabaseShardingBy Long orderId);

    @SQL("SELECT * FROM #table WHERE order_id = :1")
    @UseMaster
    OrderEntity getOrderByIdFromMaster(@TableShardingBy @DatabaseShardingBy Long orderId);

6、单元测试

@SpringBootTest(classes = {Application.class})
@RunWith(SpringJUnit4ClassRunner.class)
public class ShardingTest {
    @Autowired
    OrderPartitionByIdDao orderPartitionByIdDao;

    @Autowired
    OrderPartitionByUserIdDao orderPartitionByUserIdDao;

    @Test
    public void testCreateOrderRandom() {
        for (int i = 0; i < 20; i++) {
            int userId = ThreadLocalRandom.current().nextInt(1000,1000000);
            OrderEntity orderEntity = new OrderEntity();
            orderEntity.setOrderId(SeqIdUtil.nextId(userId % ShardingStrategyConstant.SHARDING_TABLE_NUM));
            orderEntity.setStatus(1);
            orderEntity.setUserId(userId);
            orderEntity.setCreateTime(new Date());
            orderEntity.setUpdateTime(new Date());
            orderEntity.setBookingDate(new Date());
            int ret = orderPartitionByIdDao.insertOrder(orderEntity);
            Assert.assertEquals(1, ret);
        }
    }

    @Test
    public void testOrderAll() {
        //insert
        int userId = ThreadLocalRandom.current().nextInt(1000,1000000);
        OrderEntity orderEntity = new OrderEntity();
        orderEntity.setOrderId(SeqIdUtil.nextId(userId % ShardingStrategyConstant.SHARDING_TABLE_NUM));
        orderEntity.setStatus(1);
        orderEntity.setUserId(userId);
        orderEntity.setCreateTime(new Date());
        orderEntity.setUpdateTime(new Date());
        orderEntity.setBookingDate(new Date());
        int i = orderPartitionByIdDao.insertOrder(orderEntity);
        Assert.assertEquals(1, i);

        //get from master
        OrderEntity orderInfo = orderPartitionByIdDao.getOrderByIdFromMaster(orderEntity.getOrderId());
        Assert.assertNotNull(orderInfo);
        Assert.assertEquals(orderInfo.getOrderId(), orderEntity.getOrderId());

        //get from slave
        OrderEntity slaveOrderInfo = orderPartitionByIdDao.getOrderById(orderEntity.getOrderId());
        Assert.assertNotNull(slaveOrderInfo);
        //update
        OrderEntity updateEntity = new OrderEntity();
        updateEntity.setOrderId(orderInfo.getOrderId());
        updateEntity.setStatus(2);
        updateEntity.setUpdateTime(new Date());
        int affectRows = orderPartitionByIdDao.updateOrderByOrderId(updateEntity);
        Assert.assertTrue( affectRows > 0);
    }

    @Test
    public void testGetListByUserId() {
        int userId = ThreadLocalRandom.current().nextInt(1000,1000000);
        for (int i = 0; i < 5; i++) {
            OrderEntity orderEntity = new OrderEntity();
            orderEntity.setOrderId(SeqIdUtil.nextId(userId % ShardingStrategyConstant.SHARDING_TABLE_NUM));
            orderEntity.setStatus(1);
            orderEntity.setUserId(userId);
            orderEntity.setCreateTime(new Date());
            orderEntity.setUpdateTime(new Date());
            orderEntity.setBookingDate(new Date());
            orderPartitionByIdDao.insertOrder(orderEntity);
        }
        try {
            //防止主从延迟引起的校验错误
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        List<OrderEntity> orderListByUserId = orderPartitionByUserIdDao.getOrderListByUserId(userId);
        Assert.assertNotNull(orderListByUserId);
        Assert.assertTrue(orderListByUserId.size() == 5);
    }
}

大功告成:

四、总结

本篇主要介绍Java版使用Mango框架实现Mysql分库分表实战，分库分表中间件也可以使用类似于ShardingJDBC，或者自研。

以上分库分表数量仅供演示参考，实际工作中分表数量、分库数量、是根据公司实际业务数据增长速度, 高峰期QPS,物理机器配置等等因素计算。