MySQL單表ibd檔案恢複方法詳解

前言：
隨著innodb的普及，innobackup也成為了主流備份方式。物理備份對於建立slave，全庫恢複的需求都能從容應對。
但當面臨單表資料誤刪，或者單表誤drop的情況，如果使用物理全備進行恢複呢？
下文將進行詳細分析。
恢複過程中需要用到的工具，percona data recover tool ： https://launchpad.net/percona-innodb-recovery-tool

情況一：誤刪部分資料，需要用最近一次備份覆蓋
來自同一台機器的ibd恢複覆蓋，且備份後table沒有被recreate過。
這種情況是最簡單的，備份時的ibd檔案（後稱老ibd）中的space id和index id 與 新ibd的space id 和index id一致。
且和ibdata檔案中的space id和index id一致。因此，物理檔案可以直接覆蓋做恢複。
以下是詳細步驟

Step -1 : 物理備份
innobackupex --defaults-file=/usr/local/mysql3321/my.cnf --socket=/xfs/mysql3321/mysql.sock --user=root --password=password /xfs/backup/
Step 0 : apply log
innobackupex --apply-log --defaults-file=/usr/local/mysql3321/my.cnf /xfs/backup/2012-10-17_11-29-20/
Step 1 : 備份現在的ibd檔案（可選）
cp -a testibd.ibd testibd.bak
Step 2 : 捨棄現在ibd檔案
mysql> alter table testibd discard tablespace
Step 3 : 複本備份ibd檔案
shell> cp /xfs/backup/2012-10-17_11-29-20/test/testibd.ibd /xfs/mysql3321/test/
shell> chown mysql:mysql /xfs/mysql3321/test/testibd.ibd
Step 4 : 匯入ibd檔案
mysql> alter table testibd import tablespace

情況二：誤刪 table，表結構已經被drop了
這種情況稍複雜，不過恢複過程還是比較容易操作的。由於table被drop後的space id會留空因此備份檔案的space id不會被佔用。
我們只需要重建表結構，然後把ibdata中該表的space id還原，物理檔案可以直接覆蓋做恢複了。

Step 1 : 重建表
mysql> create table testibd (UserID int);
Step 2 : 關閉mysql服務（必須）
shell> service mysqld3321 stop
Step 3: 準備ibd檔案 apply log
shell> innobackupex --apply-log --defaults-file=/usr/local/mysql3321/my.cnf /xfs/backup/2012-10-17_11-29-20/
Step 4 : 備份現在的ibd檔案（可選）
cp -a testibd.ibd testibd.bak
Step 5 : 複本備份ibd檔案
shell> cp -a /xfs/backup/2012-10-17_11-29-20/test/testibd.ibd /xfs/mysql3321/test/
shell> chown mysql:mysql /xfs/mysql3321/test/testibd.ibd
Step 6 : 使用percona recovery tool 修改ibdata
shell> /root/install/percona-data-recovery-tool-for-innodb-0.5/ibdconnect -o /xfs/mysql3321/ibdata1 -f /xfs/mysql3321/test/testibd.ibd -d test -t testibd 複製代碼 代碼如下:Initializing table definitions...
Processing table: SYS_TABLES
- total fields: 10
- nullable fields: 6
- minimum header size: 5
- minimum rec size: 21
- maximum rec size: 555
Processing table: SYS_INDEXES
- total fields: 9
- nullable fields: 5
- minimum header size: 5
- minimum rec size: 29
- maximum rec size: 165
Setting SPACE=1 in SYS_TABLE for `test`.`testibd`
Check if space id 1 is already used
Page_id: 8, next page_id: 4294967295
Record position: 65
Checking field lengths for a row (SYS_TABLES): OFFSETS: 16 8 50 3 2 0 0 0 0 0
Db/table: infimum
Space id: 1768842857 (0x696E6669)
Next record at offset: 8D
Record position: 8D
Checking field lengths for a row (SYS_TABLES): OFFSETS: 16 11 17 24 32 36 40 48 52 52
Db/table: SYS_FOREIGN
Space id: 0 (0x0)
Next record at offset: D5
Record position: D5
Checking field lengths for a row (SYS_TABLES): OFFSETS: 16 16 22 29 37 41 45 53 57 57
Db/table: SYS_FOREIGN_COLS
Space id: 0 (0x0)
Next record at offset: 122
Record position: 122
Checking field lengths for a row (SYS_TABLES): OFFSETS: 16 12 18 25 33 37 41 49 53 53
Db/table: test/testibd
Space id: 2 (0x2)
Next record at offset: 74
Space id 1 is not used in any of the records in SYS_TABLES
Page_id: 8, next page_id: 4294967295
Record position: 65
Checking field lengths for a row (SYS_TABLES): OFFSETS: 16 8 50 3 2 0 0 0 0 0
Db/table: infimum
Space id: 1768842857 (0x696E6669)
Next record at offset: 8D
Record position: 8D
Checking field lengths for a row (SYS_TABLES): OFFSETS: 16 11 17 24 32 36 40 48 52 52
Db/table: SYS_FOREIGN
Space id: 0 (0x0)
Next record at offset: D5
Record position: D5
Checking field lengths for a row (SYS_TABLES): OFFSETS: 16 16 22 29 37 41 45 53 57 57
Db/table: SYS_FOREIGN_COLS
Space id: 0 (0x0)
Next record at offset: 122
Record position: 122
Checking field lengths for a row (SYS_TABLES): OFFSETS: 16 12 18 25 33 37 41 49 53 53
Db/table: test/testibd
Space id: 2 (0x2)
Updating test/testibd (table_id 17) with id 0x01000000
SYS_TABLES is updated successfully
Initializing table definitions...
Processing table: SYS_TABLES
- total fields: 10
- nullable fields: 6
- minimum header size: 5
- minimum rec size: 21
- maximum rec size: 555
Processing table: SYS_INDEXES
- total fields: 9
- nullable fields: 5
- minimum header size: 5
- minimum rec size: 29
- maximum rec size: 165
Setting SPACE=1 in SYS_INDEXES for TABLE_ID = 17
Page_id: 11, next page_id: 4294967295
Record position: 65
Checking field lengths for a row (SYS_INDEXES): OFFSETS: 15 8 50 7 2 0 0 0 0
TABLE_ID: 3798561113125514496
SPACE: 1768842857
Next record at offset: 8C
Record position: 8C
Checking field lengths for a row (SYS_INDEXES): OFFSETS: 15 8 16 22 29 35 39 43 47
TABLE_ID: 11
SPACE: 0
Next record at offset: CE
Record position: CE
Checking field lengths for a row (SYS_INDEXES): OFFSETS: 15 8 16 22 29 36 40 44 48
TABLE_ID: 11
SPACE: 0
Next record at offset: 111
Record position: 111
Checking field lengths for a row (SYS_INDEXES): OFFSETS: 15 8 16 22 29 36 40 44 48
TABLE_ID: 11
SPACE: 0
Next record at offset: 154
Record position: 154
Checking field lengths for a row (SYS_INDEXES): OFFSETS: 15 8 16 22 29 35 39 43 47
TABLE_ID: 12
SPACE: 0
Next record at offset: 22C
Record position: 22C
Checking field lengths for a row (SYS_INDEXES): OFFSETS: 15 8 16 22 29 44 48 52 56
TABLE_ID: 17
SPACE: 2
Updating SPACE(0x00000001 , 0x01000000) for TABLE_ID: 17
sizeof(s)=4
Next record at offset: 74
SYS_INDEXES is updated successfully

Step 7 : 使用percona recovery tool 重新checksum ibdata
重複執行以下命令，直到程式沒有輸出為止。
shell> /root/install/percona-data-recovery-tool-for-innodb-0.5/innochecksum -f /xfs/mysql3321/ibdata1 複製代碼 代碼如下:page 8 invalid (fails old style checksum)
page 8: old style: calculated = 0xF4AD74CB; recorded = 0xEECB309D
fixing old checksum of page 8
page 8 invalid (fails new style checksum)
page 8: new style: calculated = 0x6F0C29B4; recorded = 0x3D02308C
fixing new checksum of page 8
page 11 invalid (fails old style checksum)
page 11: old style: calculated = 0x3908087C; recorded = 0xF9E8D30C
fixing old checksum of page 11
page 11 invalid (fails new style checksum)
page 11: new style: calculated = 0xB26CFD77; recorded = 0xDB25D39D
fixing new checksum of page 11

Step 8 : 啟動mysql服務
shell> service mysqld3321 start