Redis系列之keys命令和scan命令性能对比

项目场景

Redis的keys *命令在生产环境是慎用的，特别是一些并发量很大的项目，原因是Redis是单线程的，keys *会引发Redis锁，占用reids CPU，如果key数量很大而且并发是比较大的情况，效率是很慢的，很有可能导致服务雪崩，在Redis官方的文档是这样解释的，官方的推荐是使用scan命令或者集合
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解决方案

搭建一个工程来实践一下，项目环境：

JDK 1.8
SpringBoot 2.2.1
Maven 3.2+
Mysql 8.0.26
spring-boot-starter-data-redis 2.2.1
jedis3.1.0
开发工具
- IntelliJ IDEA
- smartGit

新建一个SpringBoot项目
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选择需要的依赖
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选择Maven项目和jdk对应的版本

<?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>2.2.1.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.example</groupId><artifactId>springboot-jedis</artifactId><version>0.0.1-SNAPSHOT</version><name>springboot-jedis</name><description>Demo project for Spring Boot</description><properties><java.version>8</java.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId><exclusions><exclusion><groupId>io.lettuce</groupId><artifactId>lettuce-core</artifactId></exclusion></exclusions></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>redis.clients</groupId><artifactId>jedis</artifactId></dependency><dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.7.11</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></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><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><configuration><source>8</source><target>8</target></configuration></plugin></plugins></build></project>

package com.example.jedis.configuration;import com.example.jedis.common.JedisTemplate;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.pool2.impl.GenericObjectPool;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.jedis.JedisConnection;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.repository.configuration.EnableRedisRepositories;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;@Configuration
@ConditionalOnClass({GenericObjectPool.class, JedisConnection.class, Jedis.class})
@EnableRedisRepositories(basePackages = "com.example.jedis.repository")
@Slf4j
public class RedisConfiguration {@Beanpublic JedisPoolConfig jedisPoolConfig() {return new JedisPoolConfig();}@Beanpublic JedisPool jedisPool() {return new JedisPool(jedisPoolConfig());}@Beanpublic RedisConnectionFactory jedisConnectionFactory() {return new JedisConnectionFactory();}@Beanpublic RedisTemplate<String, Object> redisTemplate() {RedisTemplate<String, Object> template = new RedisTemplate<String, Object>();template.setConnectionFactory(jedisConnectionFactory());template.setKeySerializer(new StringRedisSerializer());template.setValueSerializer(new GenericJackson2JsonRedisSerializer());return template;}}

写一个工具类，实现redis scan和keys *的逻辑，当然也可以直接使用RedisTemplate

import cn.hutool.core.collection.ConcurrentHashSet;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Component;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.ScanParams;
import redis.clients.jedis.ScanResult;
import redis.clients.jedis.exceptions.JedisConnectionException;
import redis.clients.jedis.exceptions.JedisDataException;
import redis.clients.jedis.exceptions.JedisException;
import redis.clients.jedis.params.SetParams;import javax.annotation.Resource;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.function.Consumer;
import java.util.function.Function;
@Component
@Slf4j
public class JedisUtil implements InitializingBean {@Resourceprivate JedisPool jedisPool;private Jedis jedis;public JedisTemplate(JedisPool jedisPool) {this.jedisPool = jedisPool;}public JedisTemplate() {}@Overridepublic void afterPropertiesSet() {jedis = jedisPool.getResource();}public <T> T execute(Function<Jedis, T> action) {T apply = null;try {jedis = jedisPool.getResource();apply = action.apply(jedis);} catch (JedisException e) {handleException(e);throw e;} finally {jedis.close();}return apply;}public void execute(Consumer<Jedis> action) {try {jedis = jedisPool.getResource();action.accept(jedis);} catch (JedisException e) {handleException(e);throw e;} finally {jedis.close();}}public JedisPool getJedisPool() {return this.jedisPool;}public Set<String> keys(final String pattern) {return execute(e->{return jedis.keys(pattern);});}public Set<String> scan(String pattern) {return execute(e->{return this.doScan(pattern);});}protected Set<String> doScan(String pattern) {Set<String> resultSet = new ConcurrentHashSet<>();String cursor = String.valueOf(0);try {do {ScanParams params = new ScanParams();params.count(300);params.match(pattern);ScanResult<String> scanResult = jedis.scan(cursor, params);cursor = scanResult.getCursor();resultSet.addAll(scanResult.getResult());} while (Integer.valueOf(cursor) > 0);} catch (NumberFormatException e) {log.error("doScan NumberFormatException:{}", e);} catch (Exception e) {log.error("doScan Exception :{}", e);}return resultSet;}protected void handleException(JedisException e) {if (e instanceof JedisConnectionException) {log.error("redis connection exception:{}", e);} else if (e instanceof JedisDataException) {log.error("jedis data exception:{}", e);} else {log.error("jedis exception:{}", e);}}}

新增测试类


import cn.hutool.core.date.DateUtil;
import cn.hutool.core.date.TimeInterval;
import cn.hutool.core.thread.ExecutorBuilder;
import cn.hutool.core.util.IdUtil;
import com.example.jedis.common.JedisTemplate;
import com.example.jedis.configuration.RedisConfiguration;
import com.example.jedis.model.UserDto;
import com.example.jedis.repository.UserRepository;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.test.annotation.DirtiesContext;
import org.springframework.test.context.ContextConfiguration;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.IntStream;@SpringBootTest
//@ContextConfiguration(classes = RedisConfiguration.class)
//@DirtiesContext(classMode = DirtiesContext.ClassMode.BEFORE_CLASS)
@Slf4j
class SpringbootJedisApplicationTests {@AutowiredJedisUtil jedisUtil;@Testvoid testCrud() {IntStream.range(0,100000).forEach(e->{final UserDto userDto = UserDto.builder().id(IdUtil.getSnowflake().nextId()).name("用户1").gender(UserDto.Gender.MALE).build();userRepository.save(userDto);});}@Testvoid testKeys() {TimeInterval timeInterval = DateUtil.timer();Set<String> setData = jedisUitil.keys("user:*");System.out.println("keys use:"+timeInterval.intervalRestart()+"ms");Set<String> setDataScan = jedisUitil.scan("user:*");System.out.println("scan use:"+timeInterval.intervalRestart()+"ms");}
}