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   -> 大数据 -> sharding-jdbc mybatis-plus 分库 分表 主从读写分离 时序数据库 -> 正文阅读

[大数据]sharding-jdbc mybatis-plus 分库 分表 主从读写分离 时序数据库

描述

本文记录了基于sharding-jdbc mybatis-plus 实现的时序数据库

本文将实现

  • sharding-jdbc 主从读写分离配置
  • sharding-jdbc 分库(水平) 分表(水平)配置
  • sharding-jdbc 分库(水平) 分表(水平)算法
  • sharding-jdbc mybatis-plus的集成
  • sharding-jdbc mybatis-plus的分页查询

shardingjdbc,mybatis-plus版本

注意其官网上的配置跟版本相关,每个版本的配置都略有改动,最新5.x的配置因为使用的人较少,不利于初学者。所以本文采用4.x版本。

maven引入

<?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>2.5.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.jisen</groupId>
    <artifactId>springboot-rws</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-mycat</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.3.1</version>
            <exclusions>
                <exclusion>
                    <groupId>com.baomidou</groupId>
                    <artifactId>mybatis-plus-generator</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!--shardingsphere-->
        <dependency>
            <groupId>org.apache.shardingsphere</groupId>
            <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
            <version>4.1.1</version>
        </dependency>
        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
            <version>2.9.9</version>
        </dependency>

        <!-- JSON 解析器和生成器 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.56</version>
        </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>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </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>

sharding jdbc 数据源配置



spring.shardingsphere.datasource.names=masterwrite0,masterwrite1,masterread0,masterread1,slaveread0,slaveread1


spring.shardingsphere.datasource.masterwrite0.jdbc-url=jdbc:mysql://192.168.43.201:3306/readwritesplit0?serverTimezone=Asia/Shanghai&useSSL=false&useUnicode=true&characterEncoding=UTF-8&rewriteBatchedStatements=true
spring.shardingsphere.datasource.masterwrite0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.masterwrite0.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.masterwrite0.username=root
spring.shardingsphere.datasource.masterwrite0.password=123456

spring.shardingsphere.datasource.masterwrite1.jdbc-url=jdbc:mysql://192.168.43.201:3306/readwritesplit1?serverTimezone=Asia/Shanghai&useSSL=false&useUnicode=true&characterEncoding=UTF-8&rewriteBatchedStatements=true
spring.shardingsphere.datasource.masterwrite1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.masterwrite1.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.masterwrite1.username=root
spring.shardingsphere.datasource.masterwrite1.password=123456


spring.shardingsphere.datasource.masterread0.jdbc-url=jdbc:mysql://192.168.43.201:3306/readwritesplit0?serverTimezone=Asia/Shanghai&useSSL=false&useUnicode=true&characterEncoding=UTF-8&rewriteBatchedStatements=true
spring.shardingsphere.datasource.masterread0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.masterread0.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.masterread0.username=root
spring.shardingsphere.datasource.masterread0.password=123456

spring.shardingsphere.datasource.masterread1.jdbc-url=jdbc:mysql://192.168.43.201:3306/readwritesplit1?serverTimezone=Asia/Shanghai&useSSL=false&useUnicode=true&characterEncoding=UTF-8&rewriteBatchedStatements=true
spring.shardingsphere.datasource.masterread1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.masterread1.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.masterread1.username=root
spring.shardingsphere.datasource.masterread1.password=123456

spring.shardingsphere.datasource.slaveread0.jdbc-url=jdbc:mysql://192.168.43.202:3306/readwritesplit0?serverTimezone=Asia/Shanghai&useSSL=false&useUnicode=true&characterEncoding=UTF-8&rewriteBatchedStatements=true
spring.shardingsphere.datasource.slaveread0.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.slaveread0.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.slaveread0.username=root
spring.shardingsphere.datasource.slaveread0.password=123456

spring.shardingsphere.datasource.slaveread1.jdbc-url=jdbc:mysql://192.168.43.202:3306/readwritesplit1?serverTimezone=Asia/Shanghai&useSSL=false&useUnicode=true&characterEncoding=UTF-8&rewriteBatchedStatements=true
spring.shardingsphere.datasource.slaveread1.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.slaveread1.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.slaveread1.username=root
spring.shardingsphere.datasource.slaveread1.password=123456

spring.shardingsphere.sharding.binding-tables=tb_keyvalue
spring.shardingsphere.props.sql.show=true

#读写分离配置库1
spring.shardingsphere.sharding.master-slave-rules.ds0.name=ds0datasource
spring.shardingsphere.sharding.master-slave-rules.ds0.load-balance-algorithm-type=round_robin
spring.shardingsphere.sharding.master-slave-rules.ds0.master-data-source-name=masterwrite0
spring.shardingsphere.sharding.master-slave-rules.ds0.slave-data-source-names=masterread0,slaveread0

#读写分离配置库2
spring.shardingsphere.sharding.master-slave-rules.ds1.name=ds1datasource
spring.shardingsphere.sharding.master-slave-rules.ds1.load-balance-algorithm-type=round_robin
spring.shardingsphere.sharding.master-slave-rules.ds1.master-data-source-name=masterwrite1
spring.shardingsphere.sharding.master-slave-rules.ds1.slave-data-source-names=masterread1, slaveread1

########################主键生成策略
spring.shardingsphere.sharding.tables.tb_keyvalue.key-generator.column=id
#spring.shardingsphere.sharding.tables.tb_keyvalue.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.tb_keyvalue.key-generator.type=NanoTimeShardingKeyGenerator


####################################################标准分片策略########################################################
#标准分片策略
spring.shardingsphere.sharding.tables.tb_keyvalue.actual-data-nodes=ds$->{0..1}.tb_keyvalue_$->{0..2}
spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.standard.precise-algorithm-class-name=com.jisen.rws.common.MyDBPreciseShardingAlgorithm
spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.standard.range-algorithm-class-name=com.jisen.rws.common.MyDBRangeShardingAlgorithm
spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.standard.sharding-column=id
#
spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.standard.precise-algorithm-class-name=com.jisen.rws.common.MyTablePreciseShardingAlgorithm
spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.standard.range-algorithm-class-name=com.jisen.rws.common.MyTableRangeShardingAlgorithm
spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.standard.sharding-column=id


#行分片策略,只能支持 = 或者 in() 的精准查询,不支持范围查询
###################################################以下为行分片策略############################################
#spring.shardingsphere.sharding.tables.tb_keyvalue.actual-data-nodes=ds$->{0..1}.tb_keyvalue_$->{0..2}
#
#spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.inline.sharding-column=id
#spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.inline.algorithm-expression=ds$->{(id / 10).toBigInteger() % 2}
#
#spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.inline.sharding-column=id
#spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.inline.algorithm-expression=tb_keyvalue_$->{id % 3}

主从库和表

  • 主从两个机器192.168.43.201(master),192.168.43.202(slave),且主从库表结构完全一致,主用于读写,从只用于读
  • master创建两个库 readwritesplit0,readwritesplit1;每个库三个表 tb_keyvalue_0,tb_keyvalue_1,tb_keyvalue_2,从库会根据binlog执行master 语句。
    在这里插入图片描述

数据源

主从请需要配置6个数据源,详情查看配置文件

masterwrite0,masterwrite1 用于写
masterread0,masterread1 用于读
slaveread0,slaveread1 用于读

主从读写分离

如下配置,读写面对两个库的读写分离,分别是masterwrite0(master和slave上的readwritesplit0),readwritesplit1(master和slave上的readwritesplit1).其中master可读可写。采用轮询法执行均衡读

#读写分离配置库1
spring.shardingsphere.sharding.master-slave-rules.ds0.name=ds0datasource
spring.shardingsphere.sharding.master-slave-rules.ds0.load-balance-algorithm-type=round_robin
spring.shardingsphere.sharding.master-slave-rules.ds0.master-data-source-name=masterwrite0
spring.shardingsphere.sharding.master-slave-rules.ds0.slave-data-source-names=masterread0,slaveread0

#读写分离配置库2
spring.shardingsphere.sharding.master-slave-rules.ds1.name=ds1datasource
spring.shardingsphere.sharding.master-slave-rules.ds1.load-balance-algorithm-type=round_robin
spring.shardingsphere.sharding.master-slave-rules.ds1.master-data-source-name=masterwrite1
spring.shardingsphere.sharding.master-slave-rules.ds1.slave-data-source-names=masterread1, slaveread1

主键以及分片算法选择

分库分表不能采用自增id,水平分布式存储需要避免主键id重复的问题。
一般采用uuid或者snowflake。
其中uuid是不带中横线的32位字符串:e.g.0f2a207c89da40b5adfc1fbc1fb2ec82
snowflake是long类型长整型:e.g.627088648474460160

主键决定了如何均衡的将记录插入水平分库分表的6个表中。
可插入的库表
master.readwrirtesplite0.tb_keyvalue_0
master.readwrirtesplite0.tb_keyvalue_1
master.readwrirtesplite0.tb_keyvalue_2
master.readwrirtesplite1.tb_keyvalue_0
master.readwrirtesplite1.tb_keyvalue_1
master.readwrirtesplite1.tb_keyvalue_2

如果是uuid可以将字符串转化位hashCode再取模的方式
Math.abs(“uuid”.hashCode())%3
则表的分片算法可以用Math.abs(“uuid”.hashCode())%3来计算

那么库的分片算法如何
可采用十位来计算
即Math.abs(“uuid”.hashCode())/10%2

snowflake是长整形
库分片算法 (627088648474460160/10).toBigInteger()%2
表分片算法 627088648474460160%2

时序数据库

时序数据库的特点是数据量大,数据类型比较单一,牺牲掉了关系型数据库事务的特性,且跟采集时间密切相关

当前时序数据库influxdb或者tdengin时序数据库,将时间作为主键以提高数据库性能,重复的时间主键将会被丢弃。因此需要非常精确的时间主键。

纳秒时间戳,毫秒级的基础下有一百万的数据容量。这个时间戳完全适用大规模数据情况,并且可以当作时间字段

nanoTime是系统纳秒级别的测量方法api,只记录系统经过时间。cpu一个周期也是纳秒级别,因此在单机情况(同一虚拟机实例)下可以不必考虑多线程导致Nanotime重复的问题。但是如果是分布式部署,不同的系统中其基准不一致,因此如果需要完全不重复的时间戳可采用redis获取微妙时间(类似于分布式锁)。

public class NanoTimeUtils {
    public static Long getNanoTime() {
        long currentTimeMillis = System.currentTimeMillis();
        long nanoTime = System.nanoTime();
        System.out.println("获取纳秒时间戳:"+(currentTimeMillis * 1000000L + nanoTime/100 % 1000000L));
        return currentTimeMillis * 1000000L + nanoTime/100 % 1000000L;
    }
}

时序数据库中,有库,超级表,表的概念。将同种设备的数据归于超级表,每个设备的数据放置于单个表中。这类似于关系型数据库的分片功能

mysql实现的分库分表中要实现时序数据的特点,就需要将设备分片,同个设备中了减轻单设备数据量过大的问题又可以根据时间(天,月)水平分表。
device_mac_time
device_mac0_time0
device_mac0_time1
device_mac2_time0
device_mac2_time1

shardingjdbc自定义主键

  • 配置文件
########################主键生成策略
spring.shardingsphere.sharding.tables.tb_keyvalue.key-generator.column=id
#spring.shardingsphere.sharding.tables.tb_keyvalue.key-generator.type=SNOWFLAKE
spring.shardingsphere.sharding.tables.tb_keyvalue.key-generator.type=NanoTimeShardingKeyGenerator
  • 自定义主键生成,实现ShardingKeyGenerator
package com.jisen.rws.common;

import com.jisen.rws.utils.NanoTimeUtils;
import org.apache.shardingsphere.spi.keygen.ShardingKeyGenerator;

import java.util.Properties;

/**
 * @author jisen
 * @date 2021/7/28 13:03
 */
public class NanoTimeShardingKeyGenerator implements ShardingKeyGenerator {
    @Override
    public Comparable<?> generateKey() {
        return NanoTimeUtils.getNanoTime();
    }

    @Override
    public String getType() {
        return "NanoTimeShardingKeyGenerator";
    }

    @Override
    public Properties getProperties() {
        return null;
    }

    @Override
    public void setProperties(Properties properties) {

    }
}

  • spi方式注入主键生成类
  1. classpath下创建META-INF.services包目录,
  2. 添加org.apache.shardingsphere.spi.keygen.ShardingKeyGenerator文件
  3. 内容为实现的主键生成类的全限定类名e.g. com.jisen.rws.common.NanoTimeShardingKeyGenerator

在这里插入图片描述

分库分表配置

  • inline 分片策略
    只能支持精确查找 = 或者 in() 的精准查询,不支持> < between and 范围查询

#行分片策略,只能支持 = 或者 in() 的精准查询,不支持范围查询
###################################################以下为行分片策略############################################
#spring.shardingsphere.sharding.tables.tb_keyvalue.actual-data-nodes=ds$->{0..1}.tb_keyvalue_$->{0..2}
#
#spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.inline.sharding-column=id
#spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.inline.algorithm-expression=ds$->{(id / 10).toBigInteger() % 2}
#
#spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.inline.sharding-column=id
#spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.inline.algorithm-expression=tb_keyvalue_$->{id % 3}

  • 标准分片策略

库和表的分片配置如下,需要指定precise和range两种分片算法的实现,

sql中精确查找 = ,in()将会走precise算法
sql中范围查找 >= ,<,between and 将会走range算法


####################################################标准分片策略########################################################
#标准分片策略
spring.shardingsphere.sharding.tables.tb_keyvalue.actual-data-nodes=ds$->{0..1}.tb_keyvalue_$->{0..2}
spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.standard.precise-algorithm-class-name=com.jisen.rws.common.MyDBPreciseShardingAlgorithm
spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.standard.range-algorithm-class-name=com.jisen.rws.common.MyDBRangeShardingAlgorithm
spring.shardingsphere.sharding.tables.tb_keyvalue.database-strategy.standard.sharding-column=id
#
spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.standard.precise-algorithm-class-name=com.jisen.rws.common.MyTablePreciseShardingAlgorithm
spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.standard.range-algorithm-class-name=com.jisen.rws.common.MyTableRangeShardingAlgorithm
spring.shardingsphere.sharding.tables.tb_keyvalue.table-strategy.standard.sharding-column=id
  1. MyDBPreciseShardingAlgorithm
package com.jisen.rws.common;

import org.apache.shardingsphere.api.sharding.standard.PreciseShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.PreciseShardingValue;

import java.util.Collection;

/**
 * @author jisen
 * @date 2021/7/27 15:29
 */
public class MyDBPreciseShardingAlgorithm implements PreciseShardingAlgorithm<Long> {

    @Override
    public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Long> shardingValue) {
        for (String tableName : availableTargetNames) {
            if (tableName.endsWith((shardingValue.getValue()/10) % 2 + "")) {
                return tableName;
            }
        }
        throw new IllegalArgumentException();
    }

}
  1. MyDBRangeShardingAlgorithm
package com.jisen.rws.common;

import org.apache.shardingsphere.api.sharding.standard.RangeShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.RangeShardingValue;
import java.util.Collection;

/**
 * 范围分片查询算法
 *
 * @author jisen
 * @date 2021/7/27 15:29
 */
public class MyDBRangeShardingAlgorithm implements RangeShardingAlgorithm<Long> {

    @Override
    public Collection<String> doSharding(Collection<String> collection, RangeShardingValue<Long> rangeShardingValue) {
        return collection;

    }
}
  1. MyTablePreciseShardingAlgorithm
package com.jisen.rws.common;

import org.apache.shardingsphere.api.sharding.standard.PreciseShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.PreciseShardingValue;

import java.util.Collection;

/**
 * @author jisen
 * @date 2021/7/27 16:44
 */
public class MyTablePreciseShardingAlgorithm implements PreciseShardingAlgorithm<Long> {

    @Override
    public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Long> shardingValue) {
        for (String tableName : availableTargetNames) {
            if (tableName.endsWith(shardingValue.getValue() % 3 + "")) {
                return tableName;
            }
        }
        throw new IllegalArgumentException();
    }

}
  1. MyTableRangeShardingAlgorithm
package com.jisen.rws.common;

import org.apache.shardingsphere.api.sharding.standard.RangeShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.RangeShardingValue;

import java.util.Collection;

/**
 * @author jisen
 * @date 2021/7/27 16:44
 */
public class MyTableRangeShardingAlgorithm implements RangeShardingAlgorithm<Long> {
    @Override
    public Collection<String> doSharding(Collection<String> collection, RangeShardingValue<Long> rangeShardingValue) {
        return collection;
    }
}

mybatis-plus集成

分页查询,需要开启分页插件

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }

源码,至此主从读写分离,水平分库分表,已经配置完成,代码如下

https://gitee.com/jisen_zhong/springboot-rws.git

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