redis集群负载均衡失效

旧城等待， 2023-03-04 10:30 7阅读 0赞

集群配置

1.  公司内部使用cache-client (搜狐开源缓存 [https://github.com/sohutv/cachecloud][https_github.com_sohutv_cachecloud])
2.  一个取经团或者某个中心下使用一个appId(项目只需要配置appId，引入cache-client依赖即可使用缓存)

原因分析

1.  拉取我们取经团下部分key分析，确认是否为这部分key导致(通过RDB文件备份起来；并以json格式解析存储) – 由于项目使用key过多 没有发现问题
2.  确认key或value中是否有 “\{” 或 “\}” ，因为有这两个字符会导致根据key生成hash值，落到集群节点上的槽失效![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaWdhbmcyMDA4MjBjaGVuZ2R1_size_16_color_FFFFFF_t_70]
    
     *  Redis对数据的特征值（一般是key）计算哈希值，使用的算法是CRC16
     *  CRC16算法参见 [https://blog.csdn.net/huang\_shiyang/article/details/50881305][https_blog.csdn.net_huang_shiyang_article_details_50881305]
     *  根据哈希值，计算数据属于那个槽
     *  根据槽与节点的映射关系，计算数据属于哪个节点
     *  参见 [https://cloud.tencent.com/developer/article/1460946][https_cloud.tencent.com_developer_article_1460946]
3.  发现大key或者value
    
     *  redis-cli --bigkeys
     *  最终定位到key userIntention\_\*\*\*\* 存在百万级value情况
     *  导致集群中同一节点内存被占满
     *  参见 [https://www.cnblogs.com/svan/p/7050396.html?utm\_source=itdadao&utm\_medium=referral][https_www.cnblogs.com_svan_p_7050396.html_utm_source_itdadao_utm_medium_referral]

问题解决

1.  确认是代码中使用hset导致
2.  通过底层源码可知 hset使用为同一个key  
    ![在这里插入图片描述][20190902101047450.png]
3.  field只是作为一个属性
4.  官方中文文档有，但当时没有真正理解([http://redisdoc.com/hash/hset.html][http_redisdoc.com_hash_hset.html])  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaWdhbmcyMDA4MjBjaGVuZ2R1_size_16_color_FFFFFF_t_70 1]
5.  使用set、setEx替换即可

延伸阅读

*  如何处理redis集群中的hot Key [https://blog.csdn.net/harleylau/article/details/86246806][https_blog.csdn.net_harleylau_article_details_86246806]

参见文档

*   redis-shake数据同步&迁移工具 [https://yq.aliyun.com/articles/691794][https_yq.aliyun.com_articles_691794]
 *   Redis集群性能问题深度分析 [https://blog.51cto.com/jerrymin/1981560][https_blog.51cto.com_jerrymin_1981560]
 *   如何提取Redis中的大KEY [https://www.cnblogs.com/svan/p/7050396.html?utm\_source=itdadao&utm\_medium=referral][https_www.cnblogs.com_svan_p_7050396.html_utm_source_itdadao_utm_medium_referral]
 *   
 *   
 *   
 *  [https://blog.csdn.net/weigang200820chengdu/article/details/100191342][https_blog.csdn.net_weigang200820chengdu_article_details_100191342]

[https_github.com_sohutv_cachecloud]: https://github.com/sohutv/cachecloud
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaWdhbmcyMDA4MjBjaGVuZ2R1_size_16_color_FFFFFF_t_70]: /images/20230208/ae96f8b62321446999540d49ec01dc18.png
[https_blog.csdn.net_huang_shiyang_article_details_50881305]: https://blog.csdn.net/huang_shiyang/article/details/50881305
[https_cloud.tencent.com_developer_article_1460946]: https://cloud.tencent.com/developer/article/1460946
[https_www.cnblogs.com_svan_p_7050396.html_utm_source_itdadao_utm_medium_referral]: https://www.cnblogs.com/svan/p/7050396.html?utm_source=itdadao&utm_medium=referral
[20190902101047450.png]: /images/20230208/6770b51beb6a4b5abb008b0109d734e5.png
[http_redisdoc.com_hash_hset.html]: http://redisdoc.com/hash/hset.html
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaWdhbmcyMDA4MjBjaGVuZ2R1_size_16_color_FFFFFF_t_70 1]: /images/20230208/20f0fcad669e407f82eb026660116b5d.png
[https_blog.csdn.net_harleylau_article_details_86246806]: https://blog.csdn.net/harleylau/article/details/86246806
[https_yq.aliyun.com_articles_691794]: https://yq.aliyun.com/articles/691794
[https_blog.51cto.com_jerrymin_1981560]: https://blog.51cto.com/jerrymin/1981560
[https_blog.csdn.net_weigang200820chengdu_article_details_100191342]: https://blog.csdn.net/weigang200820chengdu/article/details/100191342