[GitHub] [incubator-iotdb] qiaojialin commented on a change in pull request #575: Add CN document of TsFile

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qiaojialin commented on a change in pull request #575: Add CN document of TsFile
URL: https://github.com/apache/incubator-iotdb/pull/575#discussion_r350540698
 
 

 ##########
 File path: docs/Documentation-CHN/UserGuide/8-System Design (Developer)/1-Hierarchy.md
 ##########
 @@ -21,4 +21,399 @@
 
 # 第8章: 系统设计
 
-Coming Soon.
\ No newline at end of file
+## 1. TsFile 设计
+
+  本章是关于 TsFile 的设计细节.
+
+### 1.1 变量的存储
+
+- **大端存储**
+  - 比如： `int` `0x8` 将会被存储为 `00 00 00 08`, 而不是 `08 00 00 00`
+- **可变长的字符串类型**
+  - 存储的方式是以一个 `int` 类型的 `Size` + 字符串组成。`Size` 的值可以为 0。
+  - `Size` 指的是字符串所占的字节数，它并不一定等于字符串的长度. 
+  - 举例来说，"sensor_1" 这个字符串将被存储为 `00 00 00 08` + "sensor_1" (ASCII编码)。
+  - 另外需要注意的一点是 "Magic String"（文件签名）"TsFile000001", 因为他的 `Size(12)` 和 ASCII 编码值是固定的，所以没有必要在这个字符串前的写入 `Size` 值。
+- **数据类型的编码**
+  - 0: BOOLEAN
+  - 1: INT32 (`int`)
+  - 2: INT64 (`long`)
+  - 3: FLOAT
+  - 4: DOUBLE
+  - 5: TEXT (`String`)
+- **编码类型的编码**
+  - 0: PLAIN
+  - 1: PLAIN_DICTIONARY
+  - 2: RLE
+  - 3: DIFF
+  - 4: TS_2DIFF
+  - 5: BITMAP
+  - 6: GORILLA
+  - 7: REGULAR 
+- **压缩类型的编码**
+  - 0: UNCOMPRESSED
+  - 1: SNAPPY
+  - 2: GZIP
+  - 3: LZO (暂未实现)
 
 Review comment:
   文档要跟当前代码对应，没有就删掉，GZIP就没有

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