title: 为啥redis使用跳表(skiplist)而不是使用red-black？
desc: 当数据元素个数少于某值，redis会使用l跳表来存储元素，而不使用hash。<br>如果把跳表换成红黑树，redis的性能会有多大的变化？
topic: Redis
content: 之前所有的答案都不太靠谱（完全扯淡） 请看开发者说的，他为什么选用skiplist The Skip list There are a few reasons1 They are not very memory intensive. It's up to you basically. Changing parameters about the probability of a node to have a given number of levels will make then less memory intensive than btrees.2 A sorted set is often target of many ZRANGE or ZREVRANGE operations， that is， traver