redis

redis

简介

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spring redis集群踩坑

1. 多值操作

1. redis集群下如果进行多key操作则有可能报，原因是redis 对key hash存放在不同slot

org.springframework.data.redis.RedisSystemException: Error in execution; nested exception is io.lettuce.core.RedisCommandExecutionException: ERR 'EVALSHA' command keys must in same slot at 
org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:54) at 
org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:52) at

2. 解决方案 key 可以设置多值操作的时候使用一个slot 如下

xxx:{userId}:1
xxx:{userId}:2

2.springboot 集群宕机后

https://help.aliyun.com/zh/redis/product-overview/notice-on-lettuce-update
近期，Lettuce社区修复了在Redis异常宕机导致没有回复RST（Reset）情况下，客户端恢复时间可能长达15分钟的BUG，详情请参见redis/lettuce#2082。建议您将Lettuce客户端升级到6.3.0.RELEASE及以上版本，以规避该问题。该问题由阿里云Tair（Redis）团队于redis/lettuce#2499修复。

1. xml

<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>io.lettuce</groupId>
            <artifactId>lettuce-core</artifactId>
            <version>6.3.0.RELEASE</version>
        </dependency>

2. java

import io.lettuce.core.ClientOptions;
import io.lettuce.core.RedisClient;
import io.lettuce.core.RedisURI;
import io.lettuce.core.SocketOptions;
import io.lettuce.core.SocketOptions.KeepAliveOptions;
import io.lettuce.core.SocketOptions.TcpUserTimeoutOptions;
import io.lettuce.core.api.StatefulRedisConnection;
import io.lettuce.core.api.sync.RedisCommands;
import java.time.Duration;

public class LettuceExample {
    /**
     * Enable TCP keepalive and configure the following three parameters:
     *  TCP_KEEPIDLE = 30
     *  TCP_KEEPINTVL = 10
     *  TCP_KEEPCNT = 3
     */
    private static final int TCP_KEEPALIVE_IDLE = 30;

    /**
     * The TCP_USER_TIMEOUT parameter can avoid situations where Lettuce remains stuck in a continuous timeout loop during a failure or crash event. 
     * refer: https://github.com/lettuce-io/lettuce-core/issues/2082
     */
    private static final int TCP_USER_TIMEOUT = 30;

    private static RedisClient client = null;
    private static StatefulRedisConnection<String, String> connection = null;

    public static void main(String[] args) {
        // Replace the values of host, user, password, and port with the actual instance information. 
        String host = "r-bp1s1bt2tlq3p1****.redis.rds.aliyuncs.com";
        String user = "r-bp1s1bt2tlq3p1****";
        String password = "Da****3";
        int port = 6379;

        // Config RedisURL
        RedisURI uri = RedisURI.Builder
                .redis(host, port)
                .withAuthentication(user, password)
                .build();

        // Config TCP KeepAlive
        SocketOptions socketOptions = SocketOptions.builder()
                .keepAlive(KeepAliveOptions.builder()
                        .enable()
                        .idle(Duration.ofSeconds(TCP_KEEPALIVE_IDLE))
                        .interval(Duration.ofSeconds(TCP_KEEPALIVE_IDLE/3))
                        .count(3)
                        .build())
                .tcpUserTimeout(TcpUserTimeoutOptions.builder()
                        .enable()
                        .tcpUserTimeout(Duration.ofSeconds(TCP_USER_TIMEOUT))
                        .build())
                .build();

        client = RedisClient.create(uri);
        client.setOptions(ClientOptions.builder()
                .socketOptions(socketOptions)
                .build());
        connection = client.connect();
        RedisCommands<String, String> commands = connection.sync();

        System.out.println(commands.set("foo", "bar"));
        System.out.println(commands.get("foo"));

        // If your application exits and you want to destroy the resources, call this method. Then, the connection is closed, and the resources are released. 
        connection.close();
        client.shutdown();
    }
}