Redis系列（二）: 連集合底層實現原理都不知道，你敢說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":"一枚用心堅持寫原創的“無趣”程序猿，在自身受益的同時也讓朋友們在技術上有所提升。"}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"目錄"}]},{"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 的設計到底有多牛逼。"}]}]},{"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 底層實現原理"}]}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"SDS 的設計到底有多牛逼"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Redis 使用 C 語言編寫，但是並沒有直接使用 C 語言自帶的字符串，而是使用了 SDS 來管理字符串。接下來就來探討下爲什麼 Redis 使用了 SDS 來管理字符串。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"SDS 全稱 Simple Dynamic String，即簡單動態字符串。SDS 組成部分如下："}]},{"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 中的空閒的空間大小，圖左空閒空間爲 0，圖右空閒空間爲 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 中的內容長度，注意 len 的長度不包括 ' \\0 '（字符串以\\0 結尾是爲了使用 C 語言中現成的庫函數，而不需要重新造輪子）"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"buf：一個 char 類型的數組，用於存儲實際字符串的內容。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"SDS 的優勢"}]},{"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":"獲取字符串長度的複雜度爲 O(1)；直接可通過 len 屬性獲得字符串的長度。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":2,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"防止 buf 存儲內容溢出的問題；每次增加字符串的長度的時候先檢查 free 屬性是否能存下要增加的字符串的長度，如果不夠，則先對 buf 數組擴容，然後在將內容存入 buf 數組中。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":3,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"空間預分配&空間惰性釋放；SDS 會預先分配一部分空閒空間，當字符串內容添加時不需要做空間申請的工作，當字符串從 buf 數組中移除時，空閒出來的空間不會立馬被內存回收，防止新增字符串的內容寫入時空間不夠而臨時申請空間。"}]}]}]},{"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":"二級制安全性；由於字符串是存儲在 char 類型的數組中，即內容是以二進制的形式存儲的，所以 SDS 可以存儲任何類型的二進制數據，同時也不需要擔心數據格式轉換的問題。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"List 的實現原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在 Redis3.2 之前，List 底層採用了 ZipList 和 LinkedList 實現的，在 3.2 之後，List 底層採用了 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 滿足以下兩個條件時則一直使用 ZipList 作爲底層實現，當以下兩個條件任一一個不滿足時，則會被轉換成 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 中存儲的每個元素的長度小於 64byte"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"元素個數小於 512"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"ZipList方式 的實現原理"}]},{"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 是由一塊連續的存儲空間組成，從圖中可以看出 ZipList 沒有前後指針。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"各部分作用說明："}]},{"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：表示當前 list 的存儲元素的總長度。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"zllen：表示當前 list 存儲的元素的個數。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"zltail：表示當前 list 的頭結點的地址，通過 zltail 就是可以實現 list 的遍歷。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"zlend：表示當前 list 的結束標識。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"entry：表示存儲實際數據的節點，每個 entry 代表一個元素。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"previours_entry_length: 表示當前節點元素的長度，通過其長度可以計算出下一個元素的位置。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"encoding：表示元素的編碼格式。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"content：表示實際存儲的元素內容。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"ZipList 的優缺點比較"}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"優點：內存地址連續，省去了每個元素的頭尾節點指針佔用的內存。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"缺點：對於刪除和插入操作比較可能會觸發連鎖更新反應，比如在 list 中間插入刪除一個元素時，在插入或刪除位置後面的元素可能都需要發生相應的移動操作。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"LinkedList方式 的實現原理"}]},{"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 都比較熟悉了，是由一系列不連續的內存塊通過指針連接起來的雙向鏈表。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"各部分作用說明："}]},{"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 的頭結點；通過其可以找到 List 的頭節點。"}]}]},{"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 的尾節點；通過其可以找到 List 的尾節點。"}]}]},{"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 存儲的元素個數。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"dup：表示用於複製元素的函數。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"free：表示用於釋放元素的函數。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"match：表示用於對比元素的函數。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"QuickList方式 的實現原理"}]},{"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 版本之後，Redis 集合採用了 QuickList 作爲 List 的底層實現，QuickList 其實就是結合了 ZipList 和 LinkedList 的優點設計出來的。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"各部分作用說明："}]},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"每個 listNode 存儲一個指向 ZipList 的指針，ZipList 用來真正存儲元素的數據。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"ZipList 中存儲的元素數據總大小超過 8kb（默認大小，通過 list-max-ziplist-size 參數可以進行配置）的時候，就會重新創建出來一個 ListNode 和 ZipList，然後將其通過指針關聯起來。"}]}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"Set 的實現原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Set 集合採用了整數集合和字典兩種方式來實現的，當滿足如下兩個條件的時候，採用整數集合實現；一旦有一個條件不滿足時則採用字典來實現。"}]},{"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爲整數"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"Set 集合中的元素個數不大於 512（默認 512，可以通過修改 set-max-intset-entries 配置調整集合大小）"}]}]}]},{"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":"整數集合實現原理圖","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":"字段實現原理圖","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 的實現原理"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Zset 底層同樣採用了兩種方式來實現，分別是 ZipList 和 SkipList。當同時滿足以下兩個條件時，採用 ZipList 實現；反之採用 SkipList 實現。"}]},{"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 中保存的元素個數小於 128。（通過修改 zset-max-ziplist-entries 配置來修改）"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"Zset 中保存的所有元素長度小於 64byte。（通過修改 zset-max-ziplist-values 配置來修改）"}]}]}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"採用 ZipList 的實現原理"}]},{"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 的底層實現有些相似，對於 Zset 不同的是，其存儲是以鍵值對的方式依次排列，鍵存儲的是實際 value，值存儲的是 value 對應的分值。"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"採用 SkipList 的實現原理"}]},{"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 分爲兩部分，dict 部分是由字典實現，Zset 部分使用跳躍表實現，從圖中可以看出，dict 和跳躍表都存儲的數據，實際上 dict 和跳躍表最終使用指針都指向了同一份數據，即數據是被兩部分共享的，爲了方便表達將同一份數據展示在兩個地方。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"關於跳躍表和字典的具體實現，此處不詳細介紹，想深入瞭解的朋友自行上網查閱。"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"Hash 的實現原理。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Hash 底層實現採用了 ZipList 和 HashTable 兩種實現方式，相信看到這裏大家都比較輕車熟路了，下面來看看。Hash 結構當同時滿足如下兩個條件時底層採用了 ZipList 實現，一旦有一個條件不滿足時，就會被轉碼爲 HashTable 進行存儲。"}]},{"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 中存儲的所有元素的 key 和 value 的長度都小於 64byte。（通過修改 hash-max-ziplist-value 配置調節大小）"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"Hash 中存儲的元素個數小於 512。（通過修改 hash-max-ziplist-entries 配置調節大小）"}]}]}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"ZipList方式 的實現原理"}]},{"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":"從圖上看是不是很熟悉，其實和 Zset 的 ZipList 的實現邏輯幾乎相同，就不多介紹了。"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"HashTable方式 的實現原理"}]},{"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 實現底層採用了字段的方式實現，其中鍵存儲的內容爲 field，值存儲的是 value 值。"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"總結"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文主要介紹了 5 種基礎常用集合的底層實現原理，相信大家看完之後，在業務開發時對集合選用，同時結合業務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":"下篇文章我們來介紹 "},{"type":"text","marks":[{"type":"strong"}],"text":"Redis 數據過期策略、AOF 及 RDB 文件"},{"type":"text","text":"等內容，盡情期待。"}]},{"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":"往期推薦"}]},{"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":"你必須要知道集羣內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":"消息是如何在服務端存儲與讀取的，你真的知道嗎？"}]},{"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":"一文讀懂消費者背後的那點\"貓膩\""}]}]}]}