Redis 热 key
1、hotkeys
该方案只能针对于 key 的过期淘汰策略为 allkeys-lfu 或者 volatile-lfu 的实例。
-----查看淘汰策略 config get maxmemory-policy ----修改淘汰策略 config set maxmemory-policy volatile-lfu --查看 hotkey redis-cli -h r-xxx.redis.rds.aliyuncs.com -p 6379 -a "123456" --hotkeys redis-cli --hotkeys 查询结果反馈如下： [root@orcls ~]# redis-cli --hotkeys # Scanning the entire keyspace to find hot keys as well as # average sizes per key type. You can use -i 0.1 to sleep 0.1 sec # per 100 SCAN commands (not usually needed). Error: ERR An LFU maxmemory policy is not selected, access frequency not tracked. Please note that when switching between policies at runtime LRU and LFU data will take some time to adjust. [root@orcls ~]# redis-cli --hotkeys # Scanning the entire keyspace to find hot keys as well as # average sizes per key type. You can use -i 0.1 to sleep 0.1 sec # per 100 SCAN commands (not usually needed). -------- summary ------- Sampled 7 keys in the keyspace!
补充：LRU 和 LFU 算法区别：
LRU是从满足算法条件的数据中选择空闲时间最长的
LFU是从满足算法条件的数据中选择使用频率最低的
2、monitor
Redis 的 MONITOR 命令能够忠实地打印 Redis 中的所有请求，包括时间信息、Client 信息、命令以及 Key 信息。在发生紧急情况时，可以通过短暂执行 MONITOR 命令并将返回信息输入至文件，在关闭 MONITOR 命令后，对文件中请求进行归类分析，找出这段时间中的热 Key。
注意：由于 MONITOR 命令对 Redis 实例性能消耗较大，非特殊情况不推荐使用 MONITOR 命令。
127.0.0.1:6379> monitor OK 1684220725.203176 [0 172.16.104.32:38579] "PING" 1684220725.713214 [0 172.16.104.60:55774] "PING" 1684220725.907949 [0 172.16.104.32:38579] "INFO" 1684220726.120256 [0 172.16.104.32:38579] "PUBLISH" "__sentinel__:hello" "172.16.104.32,26379,f798a63e858bff905ca3ae7cdb2a5db16179806b,2,mymaster,172.16.104.32,6379,2" 1684220726.152986 [0 172.16.104.60:55774] "INFO" 1684220726.294286 [0 172.16.104.32:38579] "PING" 1684220726.723099 [0 172.16.104.60:55774] "PING" 1684220727.137292 [0 172.16.104.60:55774] "PUBLISH" "__sentinel__:hello" "172.16.104.60,26379,ed032bf681d56b743e74af1615dc264dc465444c,2,mymaster,172.16.104.32,6379,2" 1684220727.369043 [0 172.16.104.32:38579] "PING" 1684220727.742207 [0 172.16.104.60:55774] "PING" 1684220728.155509 [0 172.16.104.32:38579] "PUBLISH" "__sentinel__:hello" "172.16.104.32,26379,f798a63e858bff905ca3ae7cdb2a5db16179806b,2,mymaster,172.16.104.32,6379,2" 1684220728.384930 [0 172.16.104.32:38579] "PING" 1684220728.770192 [0 172.16.104.60:55774] "PING" 1684220729.158312 [0 172.16.104.60:55774] "PUBLISH" "__sentinel__:hello" "172.16.104.60,26379,ed032bf681d56b743e74af1615dc264dc465444c,2,mymaster,172.16.104.32,6379,2" 1684220729.407570 [0 172.16.104.32:38579] "PING" 1684220729.819311 [0 172.16.104.60:55774] "PING" 1684220730.196226 [0 172.16.104.32:38579] "PUBLISH" "__sentinel__:hello" "172.16.104.32,26379,f798a63e858bff905ca3ae7cdb2a5db16179806b,2,mymaster,172.16.104.32,6379,2" 1684220730.495966 [0 172.16.104.32:38579] "PING" 1684220730.837517 [0 172.16.104.60:55774] "PING" 1684220731.194453 [0 172.16.104.60:55774] "PUBLISH" "__sentinel__:hello" "172.16.104.60,26379,ed032bf681d56b743e74af1615dc264dc465444c,2,mymaster,172.16.104.32,6379,2" ^C (venv) [root@orcls demo]# ^C
