INODE結構二進位制頁分析

前言

一起分析一下INODE的二進位制檔案

bash-3.2# python py_innodb_page_info.py ../lottery_match/league_map.ibd -v
page offset 00000000, page type <File Space Header>
page offset 00000001, page type <Insert Buffer Bitmap>
page offset 00000002, page type <File Segment inode>
page offset 00000003, page type <B-tree Node>, page level <0001>
page offset 00000004, page type <B-tree Node>, page level <0000>
page offset 00000005, page type <B-tree Node>, page level <0000>
page offset 00000006, page type <B-tree Node>, page level <0000>
page offset 00000007, page type <B-tree Node>, page level <0000>
page offset 00000000, page type <Freshly Allocated Page>
Total number of page: 9:
Freshly Allocated Page: 1
Insert Buffer Bitmap: 1
File Space Header: 1
B-tree Node: 5
File Segment inode: 1

二進位制檔案

之前有算過
第一頁的起始範圍是：0x0000~0x3fff，對應offset page 0-File Space Header
第二頁的起始範圍是：0x4000~0x7fff，對應offset page 1-Insert Buffer Bitmap
第三頁的起始範圍在：0x8000~0xbfff，對應offset page 2-File Segment inode
第四頁的起始範圍在：0xc000~0xffff，對應offset page 3-<B-tree Node>, page level <0001>
…

FILE_HEADER(38B)

00008000: 'BC B4 02 0C `00 00 00 02` 00 00 00 00 00 00 00 00
00008010: 00 00 00 00 23 D4 BF F6 00 03 00 00 00 00 00 00
00008020: 00 00 00 00 01 CB' FF FF FF FF 00 00 FF FF FF FF

FIL_PAGE_OFFSET(4B)：值為00 00 00 02

List Node for Node Page List(12B)

00008020: 00 00 00 00 01 CB  'FF FF FF FF 00 00 FF FF FF FF
00008030: 00 00' 00 00 00 00 00 00 00 01 00 00 00 00 00 00

INODE Entry 01(192B)

算的時候真的要小心，不能眼花。一錯全錯！

00008030: 00 00 `00 00 00 00 00 00 00 01` `00 00 00 00` `00 00
00008040: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00` `00 00
00008050: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00` `00 00
00008060: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00` `05 D6
00008070: 69 D2` `00 00 00 03` FF FF FF FF FF FF FF FF FF FF
00008080: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008090: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000080a0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000080b0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000080c0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000080d0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000080e0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000080f0: FF FF' 00 00 00 00 00 00 00 02 00 00 00 00 00 00

3個Base代表：某個段的某個連結串列的頭節點和尾節點

Segment ID(8B)：0x01，新的段ID是以1開始的。
NOT_FULL_N_USED(4B)：在NOT_FULL連結串列中已經使用了多少個頁面。
值為：00 00 00 00
List Base Node For FREE List(16B)：完全沒有被使用並分配給該Segment的Extent連結串列。
值為：00 00 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00，指向的是預設。
List Base Node For NOT_FULL List(16B)：至少有一個Page分配給當前Segment的Extent連結串列，全部用完時，轉移到FSEG_FULL(16B)，全部釋放時，則歸還FSP_FREE。
值為：00 00 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00
List Base Node For FULL List：分配給當前Segment且Page完全使用完的Extent連結串列。
值為：00 00 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00
Magic Number(4B)：標記這個INODE Entry是否已經被初始化，初始化的意思就是把各個欄位的值都填進去了。
值為：05 D6 69 D2。如果這個數字是值的97937874，表明該INODE Entry已經初始化，否則沒有被初始化
Fragment Array Entry(4B)：記錄的是一個零散頁面的頁號。
值為：00 00 00 03。這個頁號很熟悉，就是page offset 00000003, page type <B-tree Node>, page level <0001>

INODE Entry 02(192B)

000080f0: FF FF '`00 00 00 00 00 00 00 02` `00 00 00 00` `00 00
00008100: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00` `00 00
00008110: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00` `00 00
00008120: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00` `05 D6
00008130: 69 D2` `00 00 00 05` `00 00 00 06` `00 00 00 07` FF FF
00008140: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008150: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008160: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008170: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008180: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008190: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000081a0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000081b0: FF FF' 00 00 00 00 00 00 00 03 00 00 00 00 00 00

段ID是0x02
對應的Fragment array page為00 00 00 05 00 00 00 06 00 00 00 07

INODE Entry 03(192B)

000081b0: FF FF '`00 00 00 00 00 00 00 03` `00 00 00 00` `00 00
000081c0: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00` `00 00
000081d0: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00` `00 00
000081e0: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00` `05 D6
000081f0: 69 D2` `00 00 00 04` FF FF FF FF FF FF FF FF FF FF
00008200: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008210: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008220: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008230: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008240: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008250: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008260: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008270: FF FF' 00 00 00 00 00 00 00 04 00 00 00 00 00 00

段ID是0x03
對應的Fragment array page為00 00 00 04

INODE Entry 04(192B)

00008270: FF FF '00 00 00 00 00 00 00 04 00 00 00 00 00 00
00008280: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00 00 00
00008290: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00 00 00
000082a0: 00 00 FF FF FF FF 00 00 FF FF FF FF 00 00 05 D6
000082b0: 69 D2 FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000082c0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000082d0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000082e0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
000082f0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008300: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008310: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008320: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
00008330: FF FF' 00 00 00 00 00 00 00 00 00 00 00 00 00 00

段ID是0x04
對應的Fragment array page沒有頁號。

INode Entry小結

前面說過：一個索引兩個段，該資料表有兩個索引–id(primary key)和lottery_id(unique key)。那麼理論上應該有4個段才對，也就對應4個INode Entry。從以上分析也驗證確實是4個。

根據上面的INode Entry還可以知道：
段01指向的頁號是03。索引頁-樹的層級是1
段02指向的頁號是05，06，07。資料頁-樹的層級是0
段03指向的頁號是04。資料頁
段04沒有指向頁號

這裡可以大膽的猜測：
頁號03是id的非葉子節點-索引頁，頁號05、06、07是id的葉子節點-資料頁
頁號04是lottery_id的葉子節點-資料頁，目前還沒有非葉子節點。
之所以這麼認為是因為id是主鍵–對應那句話索引即資料，資料即索引。自然佔用的記憶體更多。而lottery_id只是唯一鍵，只需儲存的值只有頁號、id,lottery_id。

這裡沒有細說List Base Node，後文繼續。

INODE二進位制分析

本作品採用《CC 協議》，轉載必須註明作者和本文連結