mysql innodb 数据恢复
前言：
随着innodb的普及，innobackup也成为了主流备份方式。物理备份对于新建slave，全库恢复的需求都能从容应对。
但当面临单表数据误删，或者单表误drop的情况，如果使用物理全备进行恢复呢？
下文将进行详细分析。
恢复过程中需要用到的工具，percona data recover tool ： https://launchpad.net/percona-innodb-recovery-tool
情况一：误删部分数据，需要用最近一次备份覆盖
来自同一台机器的ibd恢复覆盖，且备份后table没有被recreate过。
这种情况是最简单的，备份时的ibd文件（后称老ibd）中的space id和index id 与 新ibd的space id 和index id一致。
且和ibdata文件中的space id和index id一致。因此，物理文件可以直接覆盖做恢复。
以下是详细步骤
Step -1 : 物理备份
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 : 备份现在的ibd文件（可选）
cp -a testibd.ibd testibd.bak
Step 2 : 舍弃现在ibd文件
mysql> alter table testibd discard tablespace
Step 3 : 复制备份ibd文件
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 : 导入ibd文件
mysql> alter table testibd import tablespace
情况二：误删 table，表结构已经被drop了
这种情况稍复杂，不过恢复过程还是比较容易操作的。由于table被drop后的space id会留空因此备份文件的space id不会被占用。
我们只需要重建表结构，然后把ibdata中该表的space id还原，物理文件可以直接覆盖做恢复了。
Step 1 : 重建表
mysql> create table testibd (UserID int);
Step 2 : 关闭mysql服务（必须）
shell> service mysqld3321 stop
Step 3: 准备ibd文件 apply log
shell> innobackupex --apply-log --defaults-file=/usr/local/mysql3321/my.cnf /xfs/backup/2012-10-17_11-29-20/
Step 4 : 备份现在的ibd文件（可选）
cp -a testibd.ibd testibd.bak
Step 5 : 复制备份ibd文件
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
复制代码 代码如下:
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
重复执行以下命令，直到程序没有输出为止。
shell> /root/install/percona-data-recovery-tool-for-innodb-0.5/innochecksum -f /xfs/mysql3321/ibdata1
复制代码 代码如下:
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 : 启动mysql服务
shell> service mysqld3321 start