shardingsphere 水平分庫分表實戰

前言

項目初期沒有強大的 DBA, 隨着用戶增長, 訂單表愈來愈大, MySQL 的主機負載一直下不來, 致使吞吐下降

• GitHub 地址: https://github.com/lmxdawn/sharding-spring-boot-mybatis-example

訂單業務分析

表結構:

CREATE TABLE `order_0` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `order_id` bigint(20) unsigned NOT NULL,
  `uid` bigint(20) unsigned NOT NULL,
  `money` int(11) NOT NULL,
  `status` tinyint(3) unsigned NOT NULL DEFAULT '0',
  `create_time` datetime NOT NULL,
  `modified_time` datetime NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk_order_id` (`order_id`),
  KEY `idx_uid` (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=20 DEFAULT CHARSET=utf8mb4

問題分析:

因爲是單 key 業務, 只須要經過 uid 來查詢, 則按照 uid 來作分表因子

分庫中間件

通過一些權衡, 仍是準備使用 shardingsphere ,社區活躍度也比較不錯

開始使用

jdk 8 , shardingsphere 版本 4.0.0-RC2

路由規則

• 分 2 個庫, 一個庫 4 張表
• 路由計算, 庫: uid % 2個庫
• 路由計算, 表: uid / 2個庫 % 4張表 (取商後再取餘, 這裏要注意取商有小數須要強轉爲整型後再取餘)

uid	uid % 2 (庫)	uid / 2 % 4 (表)
1	1	0
2	0	1
3	1	1
4	0	2
5	1	2
6	0	3
7	1	3
8	0	0

MySQL 結構

• 先建立兩個庫, db0 和 db1
• 把下面的結構分別導入兩個庫中

CREATE TABLE `order_0` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `order_id` bigint(20) unsigned NOT NULL,
  `uid` bigint(20) unsigned NOT NULL,
  `money` int(11) NOT NULL,
  `status` tinyint(3) unsigned NOT NULL DEFAULT '0',
  `create_time` datetime NOT NULL,
  `modified_time` datetime NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk_order_id` (`order_id`),
  KEY `idx_uid` (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=20 DEFAULT CHARSET=utf8mb4
CREATE TABLE `order_1` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `order_id` bigint(20) unsigned NOT NULL,
  `uid` bigint(20) unsigned NOT NULL,
  `money` int(11) NOT NULL,
  `status` tinyint(3) unsigned NOT NULL DEFAULT '0',
  `create_time` datetime NOT NULL,
  `modified_time` datetime NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk_order_id` (`order_id`),
  KEY `idx_uid` (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=20 DEFAULT CHARSET=utf8mb4
CREATE TABLE `order_2` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `order_id` bigint(20) unsigned NOT NULL,
  `uid` bigint(20) unsigned NOT NULL,
  `money` int(11) NOT NULL,
  `status` tinyint(3) unsigned NOT NULL DEFAULT '0',
  `create_time` datetime NOT NULL,
  `modified_time` datetime NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk_order_id` (`order_id`),
  KEY `idx_uid` (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=20 DEFAULT CHARSET=utf8mb4
CREATE TABLE `order_3` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `order_id` bigint(20) unsigned NOT NULL,
  `uid` bigint(20) unsigned NOT NULL,
  `money` int(11) NOT NULL,
  `status` tinyint(3) unsigned NOT NULL DEFAULT '0',
  `create_time` datetime NOT NULL,
  `modified_time` datetime NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk_order_id` (`order_id`),
  KEY `idx_uid` (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=20 DEFAULT CHARSET=utf8mb4

spring boot 的 pom.xml

<!--web-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<!--自動生成 GET SET-->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

<!--鏈接池-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.12</version>
</dependency>

<!--MySQL-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

<!--mybatis -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>

<dependency>
    <groupId>org.apache.shardingsphere</groupId>
    <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
    <version>4.0.0-RC2</version>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>

spring boot 的 application-sharding-databases.properties

spring.shardingsphere.datasource.names=db0,db1

spring.shardingsphere.datasource.db0.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.db0.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.db0.url=jdbc:mysql://localhost:3306/db0?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&zeroDateTimeBehavior=convertToNull
spring.shardingsphere.datasource.db0.username=root
spring.shardingsphere.datasource.db0.password=root

spring.shardingsphere.datasource.db1.type=com.alibaba.druid.pool.DruidDataSource
spring.shardingsphere.datasource.db1.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.db1.url=jdbc:mysql://localhost:3306/db1?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&zeroDateTimeBehavior=convertToNull
spring.shardingsphere.datasource.db1.username=root
spring.shardingsphere.datasource.db1.password=root

# 是否顯示SQL語句
spring.shardingsphere.props.sql.show=true

# 配置數據庫和表
spring.shardingsphere.sharding.tables.order.actual-data-nodes=db$->{0..1}.order_$->{0..1}
# 配置根據哪一個字段選擇數據庫
spring.shardingsphere.sharding.tables.order.database-strategy.inline.sharding-column=uid
# 配置選擇哪一個數據庫的規則
spring.shardingsphere.sharding.tables.order.database-strategy.inline.algorithm-expression=db$->{uid % 2}
# 配置選擇根據哪一個字段選擇表
spring.shardingsphere.sharding.tables.order.table-strategy.inline.sharding-column=uid
# 配置選擇哪一個表的規則
spring.shardingsphere.sharding.tables.order.table-strategy.inline.algorithm-expression=order_$->{(Integer)(uid / 2) % 4}

啓動 java web 程序

須要注意, 查詢訂單詳情須要帶上用戶 uid, 用來路由到對應的庫和表

• 建立訂單: http://localhost:8080/order/create?uid=1
• 訂單列表:http://localhost:8080/order/lists?uid=1&page=1&limit=1
• 訂單詳情:http://localhost:8080/order/detail?uid=1&orderId=373591446294364161

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