接着聊聊如何从binlog文件恢复误delete的数据，模拟Oracle的闪回功能

看腻了文章就来听听视频演示吧：https://www.bilibili.com/video/BV1cV411A7iU/

delete忘加where条件（模拟Oracle闪回）

操作基本等同于上篇：再来谈谈如何从binlog文件恢复误update的数据，模拟Oracle的回滚功能
原理：binlog的ROW模式将记录的delete语句内容转换成insert语句
步骤：

1. 查找误操作的binlog文件内容
2. binlog内容处理，转为可执行的SQL语句
3. 执行SQL恢复达到回滚效果

mysql> select * from t_student;
+------+------+-------+-------+
| id   | name | class | score |
+------+------+-------+-------+
|    1 | a    |     1 | 66    |
|    2 | b    |     1 | 58    |
|    3 | c    |     2 | 86    |
|    4 | d    |     2 | 78    |
+------+------+-------+-------+
4 rows in set (0.00 sec)

# 模拟误删数据
delete from t_student where id>2;

mysql> select * from t_student;
+------+------+-------+-------+
| id   | name | class | score |
+------+------+-------+-------+
|    1 | a    |     1 | 66    |
|    2 | b    |     1 | 58    |
+------+------+-------+-------+
2 rows in set (0.00 sec)

binlog查找到误delete语句

[root@db01 data]# mysqlbinlog --no-defaults -v -v --base64-output=decode-rows mysql-bin.000013 | sed -n '/### DELETE FROM `mdb`.`t_student`/,/COMMIT/p' > deltbl_data.txt
[root@db01 data]# cat deltbl_data.txt 
### DELETE FROM `mdb`.`t_student`
### WHERE
###   @1=3 /* INT meta=0 nullable=1 is_null=0 */
###   @2='c' /* VARSTRING(54) meta=54 nullable=1 is_null=0 */
###   @3=2 /* INT meta=0 nullable=1 is_null=0 */
###   @4='86' /* VARSTRING(54) meta=54 nullable=1 is_null=0 */
### DELETE FROM `mdb`.`t_student`
### WHERE
###   @1=4 /* INT meta=0 nullable=1 is_null=0 */
###   @2='d' /* VARSTRING(54) meta=54 nullable=1 is_null=0 */
###   @3=2 /* INT meta=0 nullable=1 is_null=0 */
###   @4='78' /* VARSTRING(54) meta=54 nullable=1 is_null=0 */
# at 2508
#230910 11:44:32 server id 3306  end_log_pos 2539 CRC32 0x7be20ca3      Xid = 571
COMMIT/*!*/;

转换成标准SQL

[root@db01 data]# cat deltbl_data.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' > instbl_data.sql
[root@db01 data]# cat instbl_data.sql 
INSERT INTO `mdb`.`t_student`
SELECT
  3 ,
  'c' ,
  2 ,
  '86' ;
INSERT INTO `mdb`.`t_student`
SELECT
  4 ,
  'd' ,
  2 ,
  '78' ;

恢复

mysql> select * from t_student;
+------+------+-------+-------+
| id   | name | class | score |
+------+------+-------+-------+
|    1 | a    |     1 | 66    |
|    2 | b    |     1 | 58    |
+------+------+-------+-------+
2 rows in set (0.00 sec)

mysql> source /mysqldata/data/instbl_data.sql
Query OK, 1 row affected (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 0

Query OK, 1 row affected (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> select * from t_student;
+------+------+-------+-------+
| id   | name | class | score |
+------+------+-------+-------+
|    1 | a    |     1 | 66    |
|    2 | b    |     1 | 58    |
|    3 | c    |     2 | 86    |
|    4 | d    |     2 | 78    |
+------+------+-------+-------+
4 rows in set (0.00 sec)