如何用ShardingSphere5.0.0-alpha實現mysql讀寫分離

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正文

需求

在前文搭建的 mysql 主從復制 (一主兩從)基礎上, 我們分別在三個 mysql 上創建了 1 個名為 miaosha的數據庫, 每個數據庫中都有 1 張用戶表 user_info.

當我們插入數據時, 數據會先插入到主庫, 然后會同步到兩個從庫上, 當我們查詢數據時, 只會去兩個從庫上查詢.

準備工作

1. 數據庫表

create database miaosha;

DROP TABLE IF EXISTS `miaosha`.`user_info`;
CREATE TABLE `miaosha`.`user_info`
(
    `id`         bigint(20)                    NOT NULL AUTO_INCREMENT,
    `user_label` varchar(32) COLLATE utf8_bin           DEFAULT NULL,
    `username`   varchar(64) COLLATE utf8_bin           DEFAULT NULL,
    `email`      varchar(64) COLLATE utf8_bin           DEFAULT NULL,
    `phone`      varchar(64) COLLATE utf8_bin           DEFAULT NULL,
    `password`   varchar(128) COLLATE utf8_bin NOT NULL,
    `active`     tinyint(4)                    NOT NULL DEFAULT '1',
    PRIMARY KEY (`id`)
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8
  COLLATE = utf8_bin;

2. pom 依賴

跟前面數據分庫分表的配置一樣.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.2.RELEASE</version>
        <relativePath/>
    </parent>
    <groupId>com.nimo</groupId>
    <artifactId>read-write-splitting-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>read-write-splitting-demo</name>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.4</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.shardingsphere</groupId>
            <artifactId>shardingsphere-jdbc-core-spring-boot-starter</artifactId>
            <version>5.0.0-alpha</version>
        </dependency>

        <!-- 阿里數據源 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.3</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

3. application.yml

再次強調下, 本文采用的 shardingsphere 版本是 5.0.0-alpha. 不同版本配置會有差異. 這里先貼出能使用的配置, 后面會對官方提供的配置進行吐槽!!!

server:
  port: 8777

spring:
  shardingsphere:
    props:
      sql-show: true
    
    # 配置 3 個數據源
    datasource:
      names: ds0,ds1,ds2
      common:
        type: com.alibaba.druid.pool.DruidDataSource
      ds0:
        url: jdbc:mysql://127.0.0.1:3306/miaosha?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2b8
        username: root
        password: '123456'
        driver-class-name: com.mysql.cj.jdbc.Driver
      ds1:
        url: jdbc:mysql://127.0.0.1:3340/miaosha?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2b8
        username: root
        password: '123456'
        driver-class-name: com.mysql.cj.jdbc.Driver
      ds2:
        url: jdbc:mysql://127.0.0.1:3341/miaosha?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2b8
        username: root
        password: '123456'
        driver-class-name: com.mysql.cj.jdbc.Driver

    rules:
      replica-query:
        load-balancers:
        	# 負載均衡算法
          round-robin:
            type: ROUND_ROBIN
            # 這里是最神經病的地方, 不配置就報錯! 配置吧又不知道配置什么
            props:
              # 你也可以配置 xxx: 123, yyy: 4342 但是必須得有一個屬性, 隨便編
              default: 0
        data-sources:
          # 這個名字就隨便起
          prds:
          	# 主庫
            primary-data-source-name: ds0
            # 從庫
            replica-data-source-names: ds1,ds2
            load-balancer-name: round_robin
    # enabled: true

mybatis:
  typeAliasesPackage: com.nimo.readwritesplitting.entity
  mapperLocations: classpath:mapper/*.xml

4. 主要代碼

// sql 
<insert id="addUser" parameterType="com.nimo.shardingdemo.entity.UserInfo">
   insert into user_info(id, username, password) values (#{id}, #{username}, #{password})
</insert>
 
 // 新增一個用戶信息
@PostMapping("userinfo")
public Object addUserInfo(@RequestBody UserInfo userInfo) {
   return userInfoMapper.addUser(userInfo);
}

5. 測試命令

# 插入用戶
curl -X POST --location "http://localhost:8777/userinfo" \
    -H "Content-Type: application/json" \
    -d "{
          \"username\": \"wangbadan\",
          \"password\": \"123456\"
        }"

# 查詢 id 為 7 的用戶
curl -X  GET http://localhost:8777/userinfo/7

下面是發起查詢兩次請求后, 打印出來的日志(有刪減).

對官網的吐槽

官方5.x 版本對 讀寫分離 的名稱進行了修改.

原先叫 read-write-splitting, 后來改為了 replica-query, 所以讀寫分離的配置也發生了變化

# 官方文檔 5.x
spring.shardingsphere.rules.readwrite-splitting.xxxxxxxxxx

# 官網 demo 5.0.0-alpha
spring.shardingsphere.rules.replica-query.xxxxxxxxxx=

但是 官網文檔關于讀寫分離的那一章節, 并沒有做修改, 還是用的 read-write-splitting, 它只是另起了一個章節, 對名稱變更做了說明.

詳細介紹請參考

github

官方文檔的變更歷史

先看下官方最新 5.x 文檔

可以看到 讀寫分離配置章節 涉及到讀寫分離的配置還是用的 readwrite-splitting

比如 spring.shardingsphere.rules.readwrite-splitting.xxxxxxxxxx

spring.shardingsphere.datasource.names= 

spring.shardingsphere.rules.readwrite-splitting.data-sources.<readwrite-splitting-data-source-name>.primary-data-source-name= 

spring.shardingsphere.rules.readwrite-splitting.data-sources.<readwrite-splitting-data-source-name>.replica-data-source-names= 

spring.shardingsphere.rules.readwrite-splitting.data-sources.<readwrite-splitting-data-source-name>.load-balancer-name= 

# Load balance algorithm configuration
spring.shardingsphere.rules.readwrite-splitting.load-balancers.<load-balance-algorithm-name>.type=

spring.shardingsphere.rules.readwrite-splitting.load-balancers.<load-balance-algorithm-name>.props.xxx=

再來看下官網提供的 demo

這里還有一個需要注意的地方, 在看官網 demo 時, 需要選擇下對應的分支/標簽.

官網 demo 提供的 讀寫分離配置 用的是 replica-query 字段, 比如: spring.shardingsphere.rules.replica-query.xxxxxxxxxx=

官網 demo 提供的配置

spring.shardingsphere.datasource.names=primary_ds,replica_ds_0,replica_ds_1

spring.shardingsphere.datasource.common.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.common.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.common.username=root
spring.shardingsphere.datasource.common.password=

# 主數據源 primary_ds
spring.shardingsphere.datasource.primary_ds.jdbc-url=jdbc:mysql://localhost:3306/demo_primary_ds?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8

# 從數據源 replica_ds_0
spring.shardingsphere.datasource.replica_ds_0.jdbc-url=jdbc:mysql://localhost:3306/demo_replica_ds_0?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8

# 從數據源 replica_ds_1
spring.shardingsphere.datasource.replica_ds_1.jdbc-url=jdbc:mysql://localhost:3306/demo_replica_ds_1?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8

# 負載均衡算法
spring.shardingsphere.rules.replica-query.load-balancers.round_robin.type=ROUND_ROBIN

# 主庫
spring.shardingsphere.rules.replica-query.data-sources.pr_ds.primary-data-source-name=primary_ds

# 從庫
spring.shardingsphere.rules.replica-query.data-sources.pr_ds.replica-data-source-names=replica_ds_0,replica_ds_1

spring.shardingsphere.rules.replica-query.data-sources.pr_ds.load-balancer-name=round_robin

最可怕的是不管是使用官網提供的 demo, 還是按照官網文檔提供的配置去配置, 項目都運行不起來.

總結

本文基于ShardingSphere5.0.0-alpha 實現了 mysql 讀寫分離, 在此之前, 還需要搭建一套 mysql 的主從復制架構.

另外, 官方 5.x 版本對 讀寫分離 的配置進行了調整, 由 readwrite-splitting 改為了 replica-query.

最后就是以下的配置不可少. props 下的配置可以隨意配置. 比如 xxx=yyy, abc=123;

當然原因還沒有搞清楚, 后面有時間會研究一下.

spring.shardingsphere.rules.readwrite-splitting.load-balancers.<load-balance-algorithm-name>.props.xxx= # 負載均衡算法屬性配置

感謝各位的閱讀，以上就是“如何用ShardingSphere5.0.0-alpha實現mysql讀寫分離”的內容了，經過本文的學習后，相信大家對如何用ShardingSphere5.0.0-alpha實現mysql讀寫分離這一問題有了更深刻的體會，具體使用情況還需要大家實踐驗證。這里是億速云，小編將為大家推送更多相關知識點的文章，歡迎關注！