MySQL中truncate誤操作后的數(shù)據(jù)恢復(fù)案例

更新時(shí)間：2015年05月09日 11:31:09 作者：吳炳錫

這篇文章主要介紹了MySQL中truncate誤操作后的數(shù)據(jù)恢復(fù)案例,主要是要從日志中定位到truncate操作的地方然后備份之前丟失的數(shù)據(jù),需要的朋友可以參考下

實(shí)際線上的場(chǎng)景比較復(fù)雜，當(dāng)時(shí)涉及了truncate, delete 兩個(gè)操作，經(jīng)確認(rèn)丟數(shù)據(jù)差不多7萬(wàn)多行，等停下來(lái)時(shí)，差不多又有共計(jì)1萬(wàn)多行數(shù)據(jù)寫入。這里為了簡(jiǎn)單說(shuō)明，只拿弄一個(gè)簡(jiǎn)單的業(yè)務(wù)場(chǎng)景舉例。

測(cè)試環(huán)境： Percona-Server-5.6.16
日志格式： mixed 沒(méi)起用gtid

表結(jié)構(gòu)如下：

CREATE TABLE `tb_wubx` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(32) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8
 
CREATE TABLE `tb_wubx` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(32) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8

基于某個(gè)時(shí)間點(diǎn)有一個(gè)備份或是有全量的binlog是能恢復(fù)數(shù)據(jù)的一個(gè)唯一保證。例如我們的備份就是一個(gè)表結(jié)構(gòu)創(chuàng)建語(yǔ)句,binlog pos相關(guān)信息： mysql-bin.000004 , 4，然后進(jìn)行了如下：

–t1時(shí)間程序?qū)懭耄?br />

insert into tb_wubx(name) values(‘張三'),(‘李四');
insert into tb_wubx(name) values(‘隔壁老王');

–t2時(shí)間某個(gè)人員失誤

truncate table tb_wubx;

–t3時(shí)間程序?qū)懭?br />

insert into tb_wubx(name) values(‘老趙');
update tb_wubx set name='老趙趙' where id=1;

現(xiàn)在表里的數(shù)據(jù)情況：

mysql>select * from tb_wubx;
+----+-----------+
| id | name |
+----+-----------+
| 1 | 老趙趙 |
+----+-----------+
1 row in set (0.00 sec)
 
mysql>select * from tb_wubx;
+----+-----------+
| id | name |
+----+-----------+
| 1 | 老趙趙 |
+----+-----------+
1 row in set (0.00 sec)

可以見(jiàn)truncate table操作后，表的自增id又變更為從1開始，原來(lái)寫入的數(shù)據(jù)應(yīng)該是：

+—-+———–+
| id | name |
+—-+———–+
| 1 | 張三 |
+—-+———–+
| 2 | 李四 |
+—-+———–+
| 3 | 隔壁老王 |
+—-+———–+

如果沒(méi)生truncate table操作，實(shí)際的數(shù)據(jù)應(yīng)該為：

+—-+———–+
| id | name |
+—-+———–+
| 1 | 張三 |
+—-+———–+
| 2 | 李四 |
+—-+———–+
| 3 | 隔壁老王 |
+—-+———–+
| 4 | 老趙趙 |
+—-+———–+

而且線上的恢復(fù)那個(gè)表時(shí)和序序開發(fā)人員了解才知道，原來(lái)那個(gè)id和緩存及其它地方有依賴，因?yàn)閕d亂了，也會(huì)造成程序錯(cuò)亂。這個(gè)時(shí)間修復(fù)id在程序?qū)渝e(cuò)亂的事，留給開發(fā)人員了關(guān)建是給他們講明白恢復(fù)的結(jié)果是什么樣，我們的關(guān)建任務(wù)是把數(shù)據(jù)恢復(fù)出來(lái)。好，接下來(lái)的工作是開始從binlog中恢復(fù)數(shù)據(jù)。
利用: show binary logs; 查看當(dāng)?shù)膌og文件分布，然后利用show binlog events in ‘binary log文件'; 查看log文件的內(nèi)容，目的是找到truncate發(fā)生的日志位置。
另外因?yàn)榛趥浞荩ㄓ蒷og的啟始位置）或是從量log, 如果基于備份有l(wèi)og的起始位置，我們需要處理的log文件是啟始位置到發(fā)生truncate的日值（后面的數(shù)據(jù)處理不了，會(huì)發(fā)生主建沖突的錯(cuò)誤造成truncate后的數(shù)據(jù)不能恢復(fù)），
如果是全量日志，需要從創(chuàng)建完mysql后庫(kù)后的日志去處理到當(dāng)前的發(fā)生truncate的位置（后面數(shù)據(jù)會(huì)因?yàn)橹鹘_突寫不進(jìn)去）
恢復(fù)準(zhǔn)備工作，創(chuàng)建一個(gè)庫(kù)用于恢復(fù)數(shù)據(jù)，這里創(chuàng)建了一個(gè)re_wubx, 及原結(jié)構(gòu)的表: tb_wubx （相當(dāng)于恢復(fù)了備份，過(guò)程省略）

mysql> show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 143 |
| mysql-bin.000002 | 261 |
| mysql-bin.000003 | 562 |
| mysql-bin.000004 | 1144 |
+------------------+-----------+
4 rows in set (0.00 sec)
 
mysql> show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 143 |
| mysql-bin.000002 | 261 |
| mysql-bin.000003 | 562 |
| mysql-bin.000004 | 1144 |
+------------------+-----------+
4 rows in set (0.00 sec)

我這里有一個(gè)備份文件就是那個(gè)創(chuàng)建表的sql語(yǔ)句，位置是mysql-bin.000004 , 4
在這個(gè)案例里我只用cover住mysql-bin.000004這個(gè)文件。

mysql>show binlog events in 'mysql-bin.000004';
+------------------+------+-------------+-----------+-------------+----------------------------------------------------+
| Log_name   | Pos | Event_type | Server_id | End_log_pos | Info |
+------------------+------+-------------+-----------+-------------+----------------------------------------------------+
| mysql-bin.000004 | 4 | Format_desc | 753306 | 120 | Server ver: 5.6.16-64.2-rel64.2-log, Binlog ver: 4 |
| mysql-bin.000004 | 120 | Query   | 753306 | 209 | use `wubx`; truncate table tb_wubx |
| mysql-bin.000004 | 209 | Query   | 753306 | 281 | BEGIN |
| mysql-bin.000004 | 281 | Table_map  | 753306 | 334 | table_id: 91 (wubx.tb_wubx) |
| mysql-bin.000004 | 334 | Write_rows | 753306 | 393 | table_id: 91 flags: STMT_END_F |
| mysql-bin.000004 | 393 | Xid   | 753306 | 424 | COMMIT /* xid=1073 */ |
| mysql-bin.000004 | 424 | Query   | 753306 | 496 | BEGIN |
| mysql-bin.000004 | 496 | Table_map  | 753306 | 549 | table_id: 91 (wubx.tb_wubx) |
| mysql-bin.000004 | 549 | Write_rows | 753306 | 602 | table_id: 91 flags: STMT_END_F |
| mysql-bin.000004 | 602 | Xid   | 753306 | 633 | COMMIT /* xid=1074 */ |
| mysql-bin.000004 | 633 | Query   | 753306 | 722 | use `wubx`; truncate table tb_wubx |
| mysql-bin.000004 | 722 | Query   | 753306 | 794 | BEGIN |
| mysql-bin.000004 | 794 | Table_map  | 753306 | 847 | table_id: 92 (wubx.tb_wubx) |
| mysql-bin.000004 | 847 | Write_rows | 753306 | 894 | table_id: 92 flags: STMT_END_F |
| mysql-bin.000004 | 894 | Xid   | 753306 | 925 | COMMIT /* xid=1081 */ |
| mysql-bin.000004 | 925 | Query   | 753306 | 997 | BEGIN |
| mysql-bin.000004 | 997 | Table_map  | 753306 | 1050 | table_id: 92 (wubx.tb_wubx) |
| mysql-bin.000004 | 1050 | Update_rows | 753306 | 1113 | table_id: 92 flags: STMT_END_F |
| mysql-bin.000004 | 1113 | Xid   | 753306 | 1144 | COMMIT /* xid=1084 */ |
+------------------+------+-------------+-----------+-------------+----------------------------------------------------+
19 rows in set (0.00 sec)
 
mysql>show binlog events in 'mysql-bin.000004';
+------------------+------+-------------+-----------+-------------+----------------------------------------------------+
| Log_name   | Pos | Event_type | Server_id | End_log_pos | Info |
+------------------+------+-------------+-----------+-------------+----------------------------------------------------+
| mysql-bin.000004 | 4 | Format_desc | 753306 | 120 | Server ver: 5.6.16-64.2-rel64.2-log, Binlog ver: 4 |
| mysql-bin.000004 | 120 | Query   | 753306 | 209 | use `wubx`; truncate table tb_wubx |
| mysql-bin.000004 | 209 | Query   | 753306 | 281 | BEGIN |
| mysql-bin.000004 | 281 | Table_map  | 753306 | 334 | table_id: 91 (wubx.tb_wubx) |
| mysql-bin.000004 | 334 | Write_rows | 753306 | 393 | table_id: 91 flags: STMT_END_F |
| mysql-bin.000004 | 393 | Xid   | 753306 | 424 | COMMIT /* xid=1073 */ |
| mysql-bin.000004 | 424 | Query   | 753306 | 496 | BEGIN |
| mysql-bin.000004 | 496 | Table_map  | 753306 | 549 | table_id: 91 (wubx.tb_wubx) |
| mysql-bin.000004 | 549 | Write_rows | 753306 | 602 | table_id: 91 flags: STMT_END_F |
| mysql-bin.000004 | 602 | Xid   | 753306 | 633 | COMMIT /* xid=1074 */ |
| mysql-bin.000004 | 633 | Query   | 753306 | 722 | use `wubx`; truncate table tb_wubx |
| mysql-bin.000004 | 722 | Query   | 753306 | 794 | BEGIN |
| mysql-bin.000004 | 794 | Table_map  | 753306 | 847 | table_id: 92 (wubx.tb_wubx) |
| mysql-bin.000004 | 847 | Write_rows | 753306 | 894 | table_id: 92 flags: STMT_END_F |
| mysql-bin.000004 | 894 | Xid   | 753306 | 925 | COMMIT /* xid=1081 */ |
| mysql-bin.000004 | 925 | Query   | 753306 | 997 | BEGIN |
| mysql-bin.000004 | 997 | Table_map  | 753306 | 1050 | table_id: 92 (wubx.tb_wubx) |
| mysql-bin.000004 | 1050 | Update_rows | 753306 | 1113 | table_id: 92 flags: STMT_END_F |
| mysql-bin.000004 | 1113 | Xid   | 753306 | 1144 | COMMIT /* xid=1084 */ |
+------------------+------+-------------+-----------+-------------+----------------------------------------------------+
19 rows in set (0.00 sec)

看到這個(gè)表剛開始就發(fā)生一次truncate, 那其實(shí)也可以說(shuō)明我就恢復(fù)剛開始那個(gè)truncate到后來(lái)那個(gè)誤操作的truncate table的語(yǔ)句之間的數(shù)據(jù)就是丟失的數(shù)據(jù)。
這個(gè)恢復(fù)可以從mysql-bin.000004 pos: 4到mysql-bin.000004 pos: 633 即：

mysqlbinlog --rewrite-db='wubx-&gt;re_wubx' --start-position=4 --stop-position=633 mysql-bin.000004 |mysql -S /tmp/mysql.sock re_wubx


mysqlbinlog --rewrite-db='wubx-&gt;re_wubx' --start-position=4 --stop-position=633 mysql-bin.000004 |mysql -S /tmp/mysql.sock re_wubx

恢復(fù)結(jié)果如下：

mysql -S /tmp/mysql.sock re_wubx;
mysql>select count(*) from tb_wubx;
+----------+
| count(*) |
+----------+
| 3 |
+----------+
1 row in set (0.02 sec)

mysql>select * from tb_wubx;
+----+--------------+
| id | name |
+----+--------------+
| 1 | 張三 |
| 2 | 李四 |
| 3 | 隔壁老王 |
+----+--------------+
3 rows in set (0.00 sec)

mysql>insert into tb_wubx(name) select name from wubx.tb_wubx;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0

mysql> rename table wubx.tb_wubx to wubx.bak_tb_wubx;
Query OK, 0 rows affected (0.04 sec)

mysql> rename table re_wubx.tb_wubx to wubx.tb_wubx;
Query OK, 0 rows affected (0.03 sec)

mysql> select * from wubx.tb_wubx;
+----+--------------+
| id | name |
+----+--------------+
| 1 | 張三 |
| 2 | 李四 |
| 3 | 隔壁老王 |
| 4 | 老趙趙 |
+----+--------------+
4 rows in set (0.00 sec)
 
mysql -S /tmp/mysql.sock re_wubx;
mysql>select count(*) from tb_wubx;
+----------+
| count(*) |
+----------+
| 3 |
+----------+
1 row in set (0.02 sec)
 
mysql>select * from tb_wubx;
+----+--------------+
| id | name |
+----+--------------+
| 1 | 張三 |
| 2 | 李四 |
| 3 | 隔壁老王 |
+----+--------------+
3 rows in set (0.00 sec)
 
mysql>insert into tb_wubx(name) select name from wubx.tb_wubx;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0
 
mysql> rename table wubx.tb_wubx to wubx.bak_tb_wubx;
Query OK, 0 rows affected (0.04 sec)
 
mysql> rename table re_wubx.tb_wubx to wubx.tb_wubx;
Query OK, 0 rows affected (0.03 sec)
 
mysql> select * from wubx.tb_wubx;
+----+--------------+
| id | name |
+----+--------------+
| 1 | 張三 |
| 2 | 李四 |
| 3 | 隔壁老王 |
| 4 | 老趙趙 |
+----+--------------+
4 rows in set (0.00 sec)

恢復(fù)完成。

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