Rcache

Rcache是基于rust实现的redis缓存。该项目是一个demo工程，主要演示了如何使用rust实现redis的核心模块。

支持的指令

• set
• get
• append
• decr
• getdel
• getrange
• getset
• incr
• incrby
• incrbyfloat
• lcs
• mget
• mset
• msetnx
• lpush
• rpush
• lpop
• rpop
• sadd
• hset
• zadd
• lrange

rdb持久化时间统计

rcache           | Rdb file has been saved,keys count is 19623,encode time cost 60ms,total time cost 60ms
rcache           | Rdb file has been saved,keys count is 227031,encode time cost 683ms,total time cost 683ms
rcache           | Rdb file has been saved,keys count is 436068,encode time cost 1322ms,total time cost 1322ms
rcache           | Rdb file has been saved,keys count is 642909,encode time cost 1951ms,total time cost 1951ms
rcache           | Rdb file has been saved,keys count is 849693,encode time cost 2579ms,total time cost 2579ms
rcache           | Rdb file has been saved,keys count is 1053635,encode time cost 3319ms,total time cost 3319ms
rcache           | Rdb file has been saved,keys count is 1256806,encode time cost 3946ms,total time cost 3946ms
rcache           | Rdb file has been saved,keys count is 1460143,encode time cost 4439ms,total time cost 4439ms
rcache           | Rdb file has been saved,keys count is 1662464,encode time cost 5153ms,total time cost 5153ms
rcache           | Rdb file has been saved,keys count is 1849100,encode time cost 6048ms,total time cost 6048ms
rcache           | Rdb file has been saved,keys count is 2045408,encode time cost 6958ms,total time cost 6958ms
rcache           | Rdb file has been saved,keys count is 2235381,encode time cost 7189ms,total time cost 7189ms
rcache           | Rdb file has been saved,keys count is 2431964,encode time cost 7577ms,total time cost 7577ms
rcache           | Rdb file has been saved,keys count is 2629802,encode time cost 8172ms,total time cost 8172ms
rcache           | Rdb file has been saved,keys count is 2827623,encode time cost 8854ms,total time cost 8854ms
rcache           | Rdb file has been saved,keys count is 3023288,encode time cost 9540ms,total time cost 9540ms
rcache           | Rdb file has been saved,keys count is 3216428,encode time cost 10372ms,total time cost 10372ms
rcache           | Rdb file has been saved,keys count is 3409558,encode time cost 6106ms,total time cost 6106ms
rcache           | Rdb file has been saved,keys count is 3519240,encode time cost 10828ms,total time cost 10828ms

可以看出rdb的时间随着key的多少而不同，300w个key的持久化时间大概在9s左右。

压测结果

通过redis-benchmark对rcache和redis进行性能对比(4核心8G内存)测试，结果如下:

总共做了三组对比实验:

• redis:原生 redis
• rcache(mpsc 的 channel 版本):rcache 的 1.0 实现，代码位于tag 0.0.1版本
• rcache(全局 mutex 版本):rcache 参考 mini-redis 实现,性能和 mini-redis 一样，代码位于主分支代码

实验结果 rcache 基于 mini-redis 的实现，性能等于 mini-redis。相比原生的 redis ，单线程吞吐量是 redis 的 90%，多线程的吞吐量是原生的 redis 的两倍。

架构

参考 mini-redis,直接用 Mutex 对全局的数据加锁,全局的 struct 内部其实就是用多个 HashMap 来存储 string,list,hash 以及过期 map 等数据结构。没想到效果出奇的好。