Redis系列（二）: 连集合底层实现原理都不知道，你敢说Redis用的很溜？

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":" "}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"一枚用心坚持写原创的“无趣”程序猿，在自身受益的同时也让朋友们在技术上有所提升。"}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"目录"}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"SDS 的设计到底有多牛逼。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"List、Set、Sorted Set、Hash 底层实现原理"}]}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"SDS 的设计到底有多牛逼"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Redis 使用 C 语言编写，但是并没有直接使用 C 语言自带的字符串，而是使用了 SDS 来管理字符串。接下来就来探讨下为什么 Redis 使用了 SDS 来管理字符串。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"SDS 全称 Simple Dynamic String，即简单动态字符串。SDS 组成部分如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/30/301e68c6ae5f6475d8dd09cd7a89ae90.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"free：表示 buf 中的空闲的空间大小，图左空闲空间为 0，图右空闲空间为 3"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"len：表示 buf 中的内容长度，注意 len 的长度不包括 ' \\0 '（字符串以\\0 结尾是为了使用 C 语言中现成的库函数，而不需要重新造轮子）"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"buf：一个 char 类型的数组，用于存储实际字符串的内容。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"SDS 的优势"}]},{"type":"numberedlist","attrs":{"start":null,"normalizeStart":1},"content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":1,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"获取字符串长度的复杂度为 O(1)；直接可通过 len 属性获得字符串的长度。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":2,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"防止 buf 存储内容溢出的问题；每次增加字符串的长度的时候先检查 free 属性是否能存下要增加的字符串的长度，如果不够，则先对 buf 数组扩容，然后在将内容存入 buf 数组中。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":3,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"空间预分配&空间惰性释放；SDS 会预先分配一部分空闲空间，当字符串内容添加时不需要做空间申请的工作，当字符串从 buf 数组中移除时，空闲出来的空间不会立马被内存回收，防止新增字符串的内容写入时空间不够而临时申请空间。"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/e8/e832d28f13ba4ea3b5005f6f7182ea87.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/fa/fa892d85df225f9ab4e87d422d562e19.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"numberedlist","attrs":{"start":"4","normalizeStart":"4"},"content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":4,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"二级制安全性；由于字符串是存储在 char 类型的数组中，即内容是以二进制的形式存储的，所以 SDS 可以存储任何类型的二进制数据，同时也不需要担心数据格式转换的问题。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"List 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在 Redis3.2 之前，List 底层采用了 ZipList 和 LinkedList 实现的，在 3.2 之后，List 底层采用了 QuickList。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Redis3.2 之前，初始化的 List 使用的 ZipList，List 满足以下两个条件时则一直使用 ZipList 作为底层实现，当以下两个条件任一一个不满足时，则会被转换成 LinkedList。"}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"List 中存储的每个元素的长度小于 64byte"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"元素个数小于 512"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"ZipList方式 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/7b/7b26ac2a2177f040ba9ea84e00896293.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"ZipList 是由一块连续的存储空间组成，从图中可以看出 ZipList 没有前后指针。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"各部分作用说明："}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"zlbytes：表示当前 list 的存储元素的总长度。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"zllen：表示当前 list 存储的元素的个数。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"zltail：表示当前 list 的头结点的地址，通过 zltail 就是可以实现 list 的遍历。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"zlend：表示当前 list 的结束标识。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"entry：表示存储实际数据的节点，每个 entry 代表一个元素。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"previours_entry_length: 表示当前节点元素的长度，通过其长度可以计算出下一个元素的位置。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"encoding：表示元素的编码格式。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"content：表示实际存储的元素内容。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"ZipList 的优缺点比较"}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"优点：内存地址连续，省去了每个元素的头尾节点指针占用的内存。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"缺点：对于删除和插入操作比较可能会触发连锁更新反应，比如在 list 中间插入删除一个元素时，在插入或删除位置后面的元素可能都需要发生相应的移动操作。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"LinkedList方式 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/4b/4b35fc9cf0145bdcd6af0b07a02c796e.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"LinkedList 都比较熟悉了，是由一系列不连续的内存块通过指针连接起来的双向链表。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"各部分作用说明："}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"head：表示 List 的头结点；通过其可以找到 List 的头节点。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"tail：表示 List 的尾节点；通过其可以找到 List 的尾节点。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"len：表示 List 存储的元素个数。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"dup：表示用于复制元素的函数。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"free：表示用于释放元素的函数。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"match：表示用于对比元素的函数。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"QuickList方式 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/d1/d1ebb253e429665da1d360a541f07e3e.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在 Redis3.2 版本之后，Redis 集合采用了 QuickList 作为 List 的底层实现，QuickList 其实就是结合了 ZipList 和 LinkedList 的优点设计出来的。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"各部分作用说明："}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"每个 listNode 存储一个指向 ZipList 的指针，ZipList 用来真正存储元素的数据。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"ZipList 中存储的元素数据总大小超过 8kb（默认大小，通过 list-max-ziplist-size 参数可以进行配置）的时候，就会重新创建出来一个 ListNode 和 ZipList，然后将其通过指针关联起来。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"Set 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Set 集合采用了整数集合和字典两种方式来实现的，当满足如下两个条件的时候，采用整数集合实现；一旦有一个条件不满足时则采用字典来实现。"}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"Set 集合中的所有元素都为整数"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"Set 集合中的元素个数不大于 512（默认 512，可以通过修改 set-max-intset-entries 配置调整集合大小）"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/6f/6ff4040d02b1225a282f6e656853c985.png","alt":null,"title":"整数集合实现原理图","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/e2/e208f44d26f53822fada26a5c8e1730a.png","alt":null,"title":"字段实现原理图","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"Zset 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Zset 底层同样采用了两种方式来实现，分别是 ZipList 和 SkipList。当同时满足以下两个条件时，采用 ZipList 实现；反之采用 SkipList 实现。"}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"Zset 中保存的元素个数小于 128。（通过修改 zset-max-ziplist-entries 配置来修改）"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"Zset 中保存的所有元素长度小于 64byte。（通过修改 zset-max-ziplist-values 配置来修改）"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"采用 ZipList 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/cf/cf0e93bc2e78ba0a3fdf42c9ee5f6c96.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"和 List 的底层实现有些相似，对于 Zset 不同的是，其存储是以键值对的方式依次排列，键存储的是实际 value，值存储的是 value 对应的分值。"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"采用 SkipList 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/ad/adb7ebdd1e51c2a8822b0cae281e1b50.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"SkipList 分为两部分，dict 部分是由字典实现，Zset 部分使用跳跃表实现，从图中可以看出，dict 和跳跃表都存储的数据，实际上 dict 和跳跃表最终使用指针都指向了同一份数据，即数据是被两部分共享的，为了方便表达将同一份数据展示在两个地方。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"关于跳跃表和字典的具体实现，此处不详细介绍，想深入了解的朋友自行上网查阅。"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"Hash 的实现原理。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Hash 底层实现采用了 ZipList 和 HashTable 两种实现方式，相信看到这里大家都比较轻车熟路了，下面来看看。Hash 结构当同时满足如下两个条件时底层采用了 ZipList 实现，一旦有一个条件不满足时，就会被转码为 HashTable 进行存储。"}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"Hash 中存储的所有元素的 key 和 value 的长度都小于 64byte。（通过修改 hash-max-ziplist-value 配置调节大小）"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"Hash 中存储的元素个数小于 512。（通过修改 hash-max-ziplist-entries 配置调节大小）"}]}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"ZipList方式 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/59/59b8be13c2b817a1f69030951a8c5679.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"从图上看是不是很熟悉，其实和 Zset 的 ZipList 的实现逻辑几乎相同，就不多介绍了。"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"HashTable方式 的实现原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/03/03fcec09204a9fb28d4e9f8cfa1bdded.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"boxShadow"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"HashTable 实现底层采用了字段的方式实现，其中键存储的内容为 field，值存储的是 value 值。"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"总结"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文主要介绍了 5 种基础常用集合的底层实现原理，相信大家看完之后，在业务开发时对集合选用，同时结合业务使用的命令更加有自己的理解。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"下篇文章我们来介绍 "},{"type":"text","marks":[{"type":"strong"}],"text":"Redis 数据过期策略、AOF 及 RDB 文件"},{"type":"text","text":"等内容，尽情期待。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"往期推荐"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"link","attrs":{"href":"http://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247483919&idx=1&sn=ee4c393dabadcecd51b34380425d227a&chksm=e8eb7b9bdf9cf28da20a8083d772d6744850256e7b338aa79225889c69f8395ab6019808d946&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"你必须要知道集群内部工作原理的一些事！"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"link","attrs":{"href":"http://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247483881&idx=1&sn=6624157a86dea60abd8a6842c863ba4e&chksm=e8eb787ddf9cf16b85561dcd25144a73304709a14f615291a5374f9ca2bf05a2284b181be1af&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"消息是如何在服务端存储与读取的，你真的知道吗？"}]},{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"link","attrs":{"href":"http://mp.weixin.qq.com/s?__biz=MzIzNTIzNzYyNw==&mid=2247483827&idx=1&sn=44cfb50953b0f745b2719977453c3a42&chksm=e8eb7827df9cf131ea8aa1496e9ec2d1ed22ed245225dad0613511006b9428fffb16c92cdd6a&scene=21#wechat_redirect","title":null},"content":[{"type":"text","text":"一文读懂消费者背后的那点\"猫腻\""}]}]}]}