深刻理解mysql----innodb_ruby工具

innodb_ruby 主要可查看innodb數據庫數據表的各類存儲，解析innodb的文件，用於學習數據庫底層的一些存儲。mysql

安裝過程

sudo gem install innodb_rubygit

gem install --user-install innodb_rubygithub

innodb_space --help # 測試一下能夠顯示一堆幫助不sql

try see see

1. 查看你數據庫的存儲文件在哪裏

mysql> show global variables like "%datadir%";
+---------------+-----------------+
| Variable_name | Value           |
+---------------+-----------------+
| datadir       | /var/lib/mysql/ |
+---------------+-----------------+
1 row in set (0.00 sec)
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2. 進入數據庫目錄

由於以後的不少命令須要填寫數據表文件路徑，每次都要寫好長，我以爲浪費時間，所以先進入了數據庫目錄。你能夠忽略這步，在以後須要填寫路徑的時候，填寫絕對路徑就ok了。數據庫

cd /var/lib/mysql/
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3. 準備好

從新建個數據庫吧ruby

mysql -uroot -p
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mysql> create database test
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mysql> use test
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4. 各類命令各類有

選項bash

-f 加載表空間，如ibd文件
-s 加載系統表空間，如ibd
-T 指定表名
-I 指定索引名
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先建立一個簡單的表markdown

mysql> CREATE TABLE innodb_ruby(
    c1 INT,
    c2 INT,
    c3 VARCHAR(10000),
    PRIMARY KEY (c1), 
    key idx(c2)
) CHARSET=ascii ROW_FORMAT=Compact;
Query OK, 0 rows affected (0.36 sec)
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插入數據oop

mysql> INSERT INTO innodb_ruby VALUES(1, 1, repeat('a', 7000)), (2, 2, repeat('b', 7000)), (3, 3, repeat('c', 7000)), (4, 4, repeat('d', 7000));
Query OK, 4 rows affected (0.00 sec)
Records: 4  Duplicates: 0  Warnings: 0
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系統文件結構

列出全部物理對象的數量。

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 system-spaces
name                            pages       indexes     
(system)                        8832        204
test/innodb_ruby                              2
...
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列出表空間中全部索引統計信息（系統空間或每一個文件表空間）

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby space-indexes
id          name                            root        fseg        used        allocated   fill_factor 
94684       PRIMARY                         3           internal    1           1           100.00%     
94684       PRIMARY                         3           leaf        3           3           100.00%     
94685       idx                             4           internal    1           1           100.00%     
94685       idx                             4           leaf        0           0           0.00%  
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id：此索引的id

name：索引名稱。PRIMARY表明的就是彙集索引，由於InnoDB表是彙集索引組織表，行記錄就是彙集索引；idx就是輔助索引的名稱。

root：索引中根節點的page號。

fseg：page類型。internal非葉子節點；leaf葉子節點

used：索引使用的page頁。

allocated：索引分配的page頁。

fill_factor：索引使用的百分比

統計每一個類型的頁共佔用了多少頁

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby space-page-type-regions
start       end         count       type                
0           0           1           FSP_HDR             
1           1           1           IBUF_BITMAP         
2           2           1           INODE               
3           7           5           INDEX               
8           8           1           FREE (ALLOCATED)
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打印每一個類型總計頁數

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby space-page-type-summary
type                count       percent     description         
INDEX               5           55.56       B+Tree index        
FSP_HDR             1           11.11       File space header   
IBUF_BITMAP         1           11.11       Insert buffer bitmap
INODE               1           11.11       File segment inode  
ALLOCATED           1           11.11       Freshly allocated
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統計全部的頁在表空間的飽和度信息，每一個頁面顯示彩色塊（按index/purpose着色），根據頁面中的數據量調整大小。

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby space-extents-illustrate
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統計全部的頁在表空間的飽和度信息，每一個頁面顯示彩色塊 (按頁面修改LSN的年齡着色)。

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby space-extents-illustrate
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頁文件結構

解釋單個頁面用途

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -p 3 page-account
Accounting for page 3:
  Page type is INDEX (B+Tree index, table and index data stored in B+Tree structure).
  Extent descriptor for pages 0-63 is at page 0, offset 158.
  Extent is not fully allocated to an fseg; may be a fragment extent.
  Page is marked as used in extent descriptor.
  Extent is in free_frag list of space.
  Page is in fragment array of fseg 1.
  Fseg is in internal fseg of index 94684.
  Index root is page 3.
  Index is test/innodb_ruby.PRIMARY.
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打印頁結構信息

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -p 3 page-dump
#<Innodb::Page::Index:0x0000000000ef65a0>:

fil header:
{:checksum=>3506321879,
 :offset=>3,
 :prev=>nil,
 :next=>nil,
 :lsn=>25811855781,
 :type=>:INDEX,
 :flush_lsn=>0,
 :space_id=>2456}

fil trailer:
{:checksum=>1027768186, :lsn_low32=>42052005}

page header:
{:n_dir_slots=>2,
 :heap_top=>162,
 :garbage_offset=>0,
 :garbage_size=>0,
 :last_insert_offset=>154,
 :direction=>:right,
 :n_direction=>2,
 :n_recs=>3,
 :max_trx_id=>0,
 :level=>1,
 :index_id=>94684,
 :n_heap=>5,
 :format=>:compact}

fseg header:
{:leaf=>
  <Innodb::Inode space=<Innodb::Space file="test/innodb_ruby.ibd", page_size=16384, pages=9>, fseg=2>,
 :internal=>
  <Innodb::Inode space=<Innodb::Space file="test/innodb_ruby.ibd", page_size=16384, pages=9>, fseg=1>}

sizes:
  header           120
  trailer            8
  directory          4
  free           16210
  used             174
  record            42
  per record     14.00

page directory:
[99, 112]

system records:
{:offset=>99,
 :header=>
  {:next=>126,
   :type=>:infimum,
   :heap_number=>0,
   :n_owned=>1,
   :min_rec=>false,
   :deleted=>false,
   :length=>5},
 :next=>126,
 :data=>"infimum\x00",
 :length=>8}
{:offset=>112,
 :header=>
  {:next=>112,
   :type=>:supremum,
   :heap_number=>1,
   :n_owned=>4,
   :min_rec=>false,
   :deleted=>false,
   :length=>5},
 :next=>112,
 :data=>"supremum",
 :length=>8}

garbage records:

records:
{:format=>:compact,
 :offset=>126,
 :header=>
  {:next=>140,
   :type=>:node_pointer,
   :heap_number=>2,
   :n_owned=>0,
   :min_rec=>true,
   :deleted=>false,
   :nulls=>[],
   :lengths=>{},
   :externs=>[],
   :length=>5},
 :next=>140,
 :type=>:clustered,
 :key=>[{:name=>"c1", :type=>"INT", :value=>1}],
 :row=>[],
 :sys=>[],
 :child_page_number=>5,
 :length=>8}

{:format=>:compact,
 :offset=>140,
 :header=>
  {:next=>154,
   :type=>:node_pointer,
   :heap_number=>3,
   :n_owned=>0,
   :min_rec=>false,
   :deleted=>false,
   :nulls=>[],
   :lengths=>{},
   :externs=>[],
   :length=>5},
 :next=>154,
 :type=>:clustered,
 :key=>[{:name=>"c1", :type=>"INT", :value=>2}],
 :row=>[],
 :sys=>[],
 :child_page_number=>6,
 :length=>8}

{:format=>:compact,
 :offset=>154,
 :header=>
  {:next=>112,
   :type=>:node_pointer,
   :heap_number=>4,
   :n_owned=>0,
   :min_rec=>false,
   :deleted=>false,
   :nulls=>[],
   :lengths=>{},
   :externs=>[],
   :length=>5},
 :next=>112,
 :type=>:clustered,
 :key=>[{:name=>"c1", :type=>"INT", :value=>4}],
 :row=>[],
 :sys=>[],
 :child_page_number=>7,
 :length=>8}
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彙總頁面記錄

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -p 3 page-records
Record 126: (c1=1) → #5
Record 140: (c1=2) → #6
Record 154: (c1=4) → #7
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每行表明一頁數據，c1=1表明c1的最小值爲1，#5表明是第5頁。

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -p 7 page-directory-summary
slot    offset  type          owned   key
0       99      infimum       1       
1       112     supremum      5       
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數據過小了，再插點數據吧

mysql> insert into innodb_ruby values(5,500,'eeee'), (6,600,'ffff'), (7, 700, 'gggg'), (8, 800, 'hhhh'), (9, 900, 'iiii'), (10, 1000, 'jjjj'), (11, 1100, 'kkkk'), (12, 1200, 'llll'), (13, 1300, 'mmmm'), (14, 1400, 'nnnn'), (15, 1500, 'oooo'), (16, 1600, 'pppp');
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root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -p 7 page-directory-summary
slot    offset  type          owned   key
0       99      infimum       1       
1       7220    conventional  4       (c1=7)
2       7348    conventional  4       (c1=11)
3       112     supremum      6
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infimum最小值，supremum最大值，1~8 其餘數據爲4~8

詳細說明一個頁的內容

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -p 7 page-illustrate
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索引結構

遍歷整個B+樹掃描索引

主鍵索引

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -I PRIMARY index-recurse
ROOT NODE #3: 3 records, 42 bytes
  NODE POINTER RECORD ≥ (c1=1) → #5
  LEAF NODE #5: 1 records, 7029 bytes
    RECORD: (c1=1) → (c2=1, c3="aaa...")
  NODE POINTER RECORD ≥ (c1=2) → #6
  LEAF NODE #6: 2 records, 14058 bytes
    RECORD: (c1=2) → (c2=2, c3="bbb...")
    RECORD: (c1=3) → (c2=3, c3="ccc...")
  NODE POINTER RECORD ≥ (c1=4) → #7
  LEAF NODE #7: 13 records, 7413 bytes
    RECORD: (c1=4) → (c2=4, c3="ddd...")
    RECORD: (c1=5) → (c2=500, c3="eeee")
    RECORD: (c1=6) → (c2=600, c3="ffff")
    RECORD: (c1=7) → (c2=700, c3="gggg")
    RECORD: (c1=8) → (c2=800, c3="hhhh")
    RECORD: (c1=9) → (c2=900, c3="iiii")
    RECORD: (c1=10) → (c2=1000, c3="jjjj")
    RECORD: (c1=11) → (c2=1100, c3="kkkk")
    RECORD: (c1=12) → (c2=1200, c3="llll")
    RECORD: (c1=13) → (c2=1300, c3="mmmm")
    RECORD: (c1=14) → (c2=1400, c3="nnnn")
    RECORD: (c1=15) → (c2=1500, c3="oooo")
    RECORD: (c1=16) → (c2=1600, c3="pppp")
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普通索引

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -I idx index-recurse
ROOT NODE #4: 16 records, 224 bytes
  RECORD: (c2=1) → (c1=1)
  RECORD: (c2=2) → (c1=2)
  RECORD: (c2=3) → (c1=3)
  RECORD: (c2=4) → (c1=4)
  RECORD: (c2=500) → (c1=5)
  RECORD: (c2=600) → (c1=6)
  RECORD: (c2=700) → (c1=7)
  RECORD: (c2=800) → (c1=8)
  RECORD: (c2=900) → (c1=9)
  RECORD: (c2=1000) → (c1=10)
  RECORD: (c2=1100) → (c1=11)
  RECORD: (c2=1200) → (c1=12)
  RECORD: (c2=1300) → (c1=13)
  RECORD: (c2=1400) → (c1=14)
  RECORD: (c2=1500) → (c1=15)
  RECORD: (c2=1600) → (c1=16)
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可看出普通索引實際上是直接指向了主鍵索引的

在索引頁中打印每條記錄的偏移量

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -I PRIMARY index-record-offsets
page_offset         record_offset       
5                   128                 
6                   128                 
6                   7157                
7                   128                 
7                   7156                
7                   7188                
7                   7220                
7                   7252                
7                   7284                
7                   7316                
7                   7348                
7                   7380                
7                   7412                
7                   7444                
7                   7476                
7                   7508  
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打印給定級別全部索引頁面的摘要信息

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -I PRIMARY -l 0 index-level-summary
page    index   level   data    free    records min_key 
5       94684   0       7029    9223    1       c1=1
6       94684   0       14058   2194    2       c1=2
7       94684   0       7413    8835    13      c1=4
root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -I PRIMARY -l 1 index-level-summary
page    index   level   data    free    records min_key 
3       94684   1       42      16210   3       c1=1
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記錄結構

給定記錄偏移量，打印記錄的詳細說明及包含的數據

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -p 5 -R 128 record-dump
Record at offset 128

Header:
  Next record offset  : 112
  Heap number         : 2
  Type                : conventional
  Deleted             : false
  Length              : 8

System fields:
  Transaction ID: 2860579
  Roll Pointer:
    Undo Log: page 897, offset 272
    Rollback Segment ID: 34
    Insert: true

Key fields:
  c1: 1

Non-key fields:
  c2: 1
  c3: "aaaa..."
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記錄歷史

顯示給定偏移量的undo日誌

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 -T test/innodb_ruby -p 5 -R 128 record-history
Transaction   Type                Undo record
(n/a)         insert              (c1=1) → ()
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顯示全部變更過的undo記錄

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 undo-history-summary
Page    Offset  Transaction   Type                Table
572     10435   2848487       delete              
...

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額外探索

表空間統計信息

root@localhost:/var/lib/mysql$ innodb_space -s ibdata1 space-lists
name                length      f_page      f_offset    l_page      l_offset    
free                53          0           3318        0           3278        
free_frag           19          0           398         0           1238        
full_frag           3           0           158         0           2238        
full_inodes         1           2           38          2           38          
free_inodes         13          1789        38          595         38
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參考文章：www.ywnds.com/?p=13677