摸透原理|一文带你了解 Redis 列表底层的实现方式

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为了节约内存而开发，它由一系列的特殊编码的的 ","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"连续内存块","attrs":{}},{"type":"text","text":" 组成的顺序型数据结构，整体结构如下：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/d6/d60ad3dbf332428525cad06554de5cfa.jpeg","alt":"","title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"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":"​","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"从上面结构可以看出来，压缩列表实际上类似与我们使用的数组，数组中每一个元素保存一个数据。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"不过与数组不同的是，压缩列表的表头存在三个字段","attrs":{}}]},{"type":"codeblock","attrs":{"lang":null},"content":[{"type":"text","text":"zlbytes\nzltail\nzllen\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"另外压缩列表的表尾还有一个字段， ","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"zlend","attrs":{}}],"attrs":{}},{"type":"text","text":" 里面保存一个特殊的值， ","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"OXFE","attrs":{}}],"attrs":{}},{"type":"text","text":" ，用于标记压缩列表的末端。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"一个压缩列表可以由多个节点构成，每个节点可以保存整数值或字节数组，结构如下：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/f0/f0b41d5f685cb93b7945752631eb69bf.jpeg","alt":"","title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"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":"​","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"使用压缩列表，如果查找定位表头元素，我们只需要使用压缩列表起始地址加上表头三个字段长度就可以直接点位，查找非常快，复杂度是 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