在数据库日常维护中，开发人员是最让人头痛的，很多时候都会由于SQL语句写的有问题导致服务器出问题，导致资源耗尽。最危险的操作就是在做DML操作的时候忘加where条件，导致全表更新，这是作为运维或者DBA的我们改如何处理呢？下面我分别针对update和delete操作忘加where条件导致全表更新的处理方法。
一. update 忘加where条件误操作恢复数据(binglog格式必须是ROW)
1.创建测试用的数据表
mysql> create table t1 (
-> id int unsigned not null auto_increment,
-> name char(20) not null,
-> sex enum('f','m') not null default 'm',
-> address varchar(30) not null,
-> primary key(id)
-> );
Query OK, 0 rows affected (0.31 sec)
mysql>
2.插入测试数据
mysql> insert into t1 (name,sex,address)values('daiiy','m','guangzhou');
Query OK, 1 row affected (0.01 sec)
mysql> insert into t1 (name,sex,address)values('tom','f','shanghai');
Query OK, 1 row affected (0.00 sec)
mysql> insert into t1 (name,sex,address)values('liany','m','beijing');
Query OK, 1 row affected (0.00 sec)
mysql> insert into t1 (name,sex,address)values('lilu','m','zhuhai');
Query OK, 1 row affected (0.05 sec)
mysql>
3.现在需要将id等于2的用户的地址改为zhuhai，update时没有添加where条件
mysql> select * from t1;
+----+-------+-----+-----------+
| id | name | sex | address |
+----+-------+-----+-----------+
| 1 | daiiy | m | guangzhou |
| 2 | tom | f | shanghai |
| 3 | liany | m | beijing |
| 4 | lilu | m | zhuhai |
+----+-------+-----+-----------+
4 rows in set (0.01 sec) mysql> update t1 set address='zhuhai';
Query OK, 3 rows affected (0.09 sec)
Rows matched: 4 Changed: 3 Warnings: 0 mysql> select * from t1;
+----+-------+-----+---------+
| id | name | sex | address |
+----+-------+-----+---------+
| 1 | daiiy | m | zhuhai |
| 2 | tom | f | zhuhai |
| 3 | liany | m | zhuhai |
| 4 | lilu | m | zhuhai |
+----+-------+-----+---------+
4 rows in set (0.00 sec) mysql>
4.开始恢复，在线上的话，应该比较复杂，要先进行锁表，以免数据再次被污染。（锁表，查看正在写哪个二进制日志）
mysql> lock tables t1 read ;
Query OK, 0 rows affected (0.00 sec) mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000024 | 1852 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec) mysql>
5.分析二进制日志，并且在其中找到相关记录，在更新时是address='zhuhai',我们可以在日志中过滤出来。
[root@localhost mysql]# mysqlbinlog --no-defaults -v -v --base64-output=DECODE-ROWS mysql-bin. | grep -B 'zhuhai'
# at
# at
# :: server id end_log_pos Table_map: `db01`.`t1` mapped to number
# :: server id end_log_pos Update_rows: table id flags: STMT_END_F
### UPDATE db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='daiiy' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='guangzhou' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### SET
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='daiiy' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='zhuhai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### UPDATE db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='tom' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='shanghai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### SET
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='tom' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='zhuhai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### UPDATE db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='liany' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='beijing' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### SET
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='liany' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='zhuhai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
可以看见里面记录了每一行的变化，这也是binglog格式要一定是row才行的原因。其中@1,@2,@3,@4,分别对应表中id,name,sex,address字段。相信大家看到这里有点明白了吧，对，没错，你猜到了，我们将相关记录转换为sql语句，重新导入数据库。
6.处理分析处理的二进制日志
[root@localhost mysql]# mysqlbinlog --no-defaults -v -v --base64-output=DECODE-ROWS mysql-bin. | sed -n '/# at 1679/,/COMMIT/p' > t1.txt
[root@localhost mysql]# cat t1.txt
# at
# :: server id end_log_pos Table_map: `db01`.`t1` mapped to number
# :: server id end_log_pos Update_rows: table id flags: STMT_END_F
### UPDATE db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='daiiy' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='guangzhou' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### SET
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='daiiy' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='zhuhai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### UPDATE db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='tom' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='shanghai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### SET
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='tom' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='zhuhai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### UPDATE db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='liany' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='beijing' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### SET
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='liany' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='zhuhai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
# at
# :: server id end_log_pos Xid =
COMMIT/*!*/;
[root@localhost mysql]#
这里sed有点复杂，需要童鞋们好好自己研究研究，这里我就不多说了。
[root@localhost mysql]# sed '/WHERE/{:a;N;/SET/!ba;s/\([^\n]*\)\n\(.*\)\n\(.*\)/\3\n\2\n\1/}' t1.txt | sed -r '/WHERE/{:a;N;/@4/!ba;s/### @2.*//g}' | sed 's/### //g;s/\/\*.*/,/g' | sed '/WHERE/{:a;N;/@1/!ba;s/,/;/g};s/#.*//g;s/COMMIT,//g' | sed '/^$/d' > recover.sql
[root@localhost mysql]# cat recover.sql
UPDATE db01.t1
SET
@= ,
@='daiiy' ,
@= ,
@='guangzhou' ,
WHERE
@= ;
UPDATE db01.t1
SET
@= ,
@='tom' ,
@= ,
@='shanghai' ,
WHERE
@= ;
UPDATE db01.t1
SET
@= ,
@='liany' ,
@= ,
@='beijing' ,
WHERE
@= ;
[root@localhost mysql]#
将文件中的@1,@2,@3,@4替换为t1表中id，name，sex，address字段，并删除最后字段的","号
[root@localhost mysql]# sed -i 's/@1/id/g;s/@2/name/g;s/@3/sex/g;s/@4/address/g' recover.sql
[root@localhost mysql]# sed -i -r 's/(address=.*),/\1/g' recover.sql
[root@localhost mysql]# cat recover.sql
UPDATE db01.t1
SET
id= ,
name='daiiy' ,
sex= ,
address='guangzhou'
WHERE
id= ;
UPDATE db01.t1
SET
id= ,
name='tom' ,
sex= ,
address='shanghai'
WHERE
id= ;
UPDATE db01.t1
SET
id= ,
name='liany' ,
sex= ,
address='beijing'
WHERE
id= ;
[root@localhost mysql]#
7.到这里日志就处理好了，现在导入即可（导入数据后，解锁表）；
mysql> source recover.sql;
Query OK, 1 row affected (0.12 sec)
Rows matched: 1 Changed: 1 Warnings: 0 Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0 Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0 mysql> select * from t1;
+----+-------+-----+-----------+
| id | name | sex | address |
+----+-------+-----+-----------+
| 1 | daiiy | m | guangzhou |
| 2 | tom | f | shanghai |
| 3 | liany | m | beijing |
| 4 | lilu | m | zhuhai |
+----+-------+-----+-----------+
4 rows in set (0.00 sec) mysql>
可以看见数据已经完全恢复，这种方法的优点是快速，方便。
二. delete 忘加where条件误删除恢复(binglog格式必须是ROW)
其实这和update忘加条件差不多，不过这处理更简单,这里就用上面那张表做测试吧
1.模拟误删除数据
mysql> select * from t1;
+----+-------+-----+-----------+
| id | name | sex | address |
+----+-------+-----+-----------+
| 1 | daiiy | m | guangzhou |
| 2 | tom | f | shanghai |
| 3 | liany | m | beijing |
| 4 | lilu | m | zhuhai |
+----+-------+-----+-----------+
4 rows in set (0.00 sec) mysql> delete from t1;
Query OK, 4 rows affected (0.03 sec) mysql> select * from t1;
Empty set (0.00 sec) mysql>
2.在binglog中去查找相关记录
[root@localhost mysql]# mysqlbinlog --no-defaults --base64-output=decode-rows -v -v mysql-bin. | sed -n '/### DELETE FROM db01.t1/,/COMMIT/p' > delete.txt
[root@localhost mysql]# cat delete.txt
### DELETE FROM db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='daiiy' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='guangzhou' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### DELETE FROM db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='tom' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='shanghai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### DELETE FROM db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='liany' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='beijing' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
### DELETE FROM db01.t1
### WHERE
### @= /* INT meta=0 nullable=0 is_null=0 */
### @='lilu' /* STRING(60) meta=65084 nullable=0 is_null=0 */
### @= /* ENUM(1 byte) meta=63233 nullable=0 is_null=0 */
### @='zhuhai' /* VARSTRING(90) meta=90 nullable=0 is_null=0 */
# at
# :: server id end_log_pos Xid =
COMMIT/*!*/;
[root@localhost mysql]#
3.将记录转换为SQL语句
[root@localhost mysql]# cat delete.txt | sed -n '/###/p' | sed 's/### //g;s/\/\*.*/,/g;s/DELETE FROM/INSERT INTO/g;s/WHERE/SELECT/g;' | sed -r 's/(@4.*),/\1;/g' | sed 's/@[1-9]=//g' > t1.sql
[root@localhost mysql]# cat t1.sql
INSERT INTO db01.t1
SELECT
,
'daiiy' ,
,
'guangzhou' ;
INSERT INTO db01.t1
SELECT
,
'tom' ,
,
'shanghai' ;
INSERT INTO db01.t1
SELECT
,
'liany' ,
,
'beijing' ;
INSERT INTO db01.t1
SELECT
,
'lilu' ,
,
'zhuhai' ;
[root@localhost mysql]#
4.导入数据，验证数据完整性
mysql> source t1.sql;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0 Query OK, 1 row affected (0.02 sec)
Records: 1 Duplicates: 0 Warnings: 0 Query OK, 1 row affected (0.02 sec)
Records: 1 Duplicates: 0 Warnings: 0 Query OK, 1 row affected (0.01 sec)
Records: 1 Duplicates: 0 Warnings: 0 mysql> select * from t1;
ERROR 1046 (3D000): No database selected
mysql> select * from db01.t1;
+----+-------+-----+-----------+
| id | name | sex | address |
+----+-------+-----+-----------+
| 1 | daiiy | m | guangzhou |
| 2 | tom | f | shanghai |
| 3 | liany | m | beijing |
| 4 | lilu | m | zhuhai |
+----+-------+-----+-----------+
4 rows in set (0.00 sec) mysql>
到这里数据就完整回来了。将binglog格式设置为row有利有弊，好处是记录了每一行的实际变化，在主从复制时也不容易出问题。但是由于记录每行的变化，会占用大量磁盘，主从复制时带宽占用会有所消耗。到底是使用row还是mixed，需要在实际工作中自己去衡量，但从整体上来说，binglog的格式设置为row，都是不二的选择。
总结：
所以在数据库操作的过程中我们需要格外小心，当然开发那边我们需要做好权限的控制，不过有一个参数可以解决我们的问题，让我们不用担心类似的问题发生：
在[mysql]段落开启这个参数：
safe-updates
这样当我们在做DML操作时忘记加where条件时，mysqld服务器是不会执行操作的：
mysql> select * from t1;
+----+------------------+
| id | name |
+----+------------------+
| 1 | yayun |
| 2 | atlas |
| 3 | mysql |
| 6 | good yayun heheh |
+----+------------------+
4 rows in set (0.00 sec) mysql> delete from t1;
ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
mysql>