MariaDB10.2新特性--Flashback

Flashback可以回滚到旧的数据，用于解决用户误删除数据的问题。

实战例子

MariaDB [zsd]> select * from test;
+------+-----------+
| id   | name      |
+------+-----------+
|    1 | 张盛东    |
|    2 | 刘忠浩    |
|    3 | 胡轲      |
+------+-----------+
3 rows in set (0.001 sec)

MariaDB [zsd]> select now();
+---------------------+
| now()               |
+---------------------+
| 2019-09-26 16:17:51 |
+---------------------+
1 row in set (0.000 sec)

MariaDB [zsd]> delete from test;
Query OK, 3 rows affected (0.012 sec)

MariaDB [zsd]> commit;
Query OK, 0 rows affected (0.000 sec)

MariaDB [zsd]> select * from test;
Empty set (0.000 sec)

对插入之前的时间点，做基于时间点的闪回查询，如下:

[mysql@oradb ~]$ mysqlbinlog /u01/data/binlog/mysql-bin.000003 -vv -d zsd -T test --start-datetime="2019-09-26 16:17:51" --flashback

mariadb它比Oracle更好的是，你知道恢复的数据是什么，如下:

/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
#190926 15:25:20 server id 30200  end_log_pos 256 CRC32 0x508a050f      Start: binlog v 4, server v 10.3.18-MariaDB-log created 190926 15:25:20 at startup
# Warning: this binlog is either in use or was not closed properly.
ROLLBACK/*!*/;
BINLOG '
4GeMXQ/4dQAA/AAAAAABAAABAAQAMTAuMy4xOC1NYXJpYURCLWxvZwAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAADgZ4xdEzgNAAgAEgAEBAQEEgAA5AAEGggAAAAICAgCAAAACgoKAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAEEwQADQgICAoKCgEPBYpQ
'/*!*/;
#190926 16:17:56 server id 30200  end_log_pos 1073 CRC32 0x57f3bac4     Annotate_rows:
#Q> delete from test
#190926 16:17:56 server id 30200  end_log_pos 1126 CRC32 0x1d0d9eaf     Table_map: `zsd`.`test` mapped to number 33
# Number of rows: 3
#190926 16:17:56 server id 30200  end_log_pos 1359 CRC32 0xb26e3c08     Xid = 98
BEGIN/*!*/;
#190926 16:17:56 server id 30200  end_log_pos 1328 CRC32 0x97af664e     Update_rows: table id 33 flags: STMT_END_F

BINLOG '
NHSMXRP4dQAANQAAAGYEAAAAACEAAAAAAAEAA3pzZAAEdGVzdAAEAw8REQQ8AAYGA6+eDR0=
NHSMXRj4dQAAygAAADAFAAAAACEAAAAAAAEABP//8AMAAAAG6IOh6L2yXYxrKARwLV2MdDQHfbTw
AwAAAAbog6HovbJdjGsoBHAtf////w9CP/ACAAAACeWImOW/oOa1qV2MauMNiCVdjHQ0B3208AIA
AAAJ5YiY5b+g5rWpXYxq4w2IJX////8PQj/wAQAAAAnlvKDnm5vkuJxdjGrjDYglXYx0NAd9tPAB
AAAACeW8oOebm+S4nF2MauMNiCV/////D0I/Tmavlw==
'/*!*/;
### UPDATE `zsd`.`test`
### WHERE
###   @1=3 /* INT meta=0 nullable=1 is_null=0 */
###   @2='胡轲' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */
###   @3=1569483560.290861 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
###   @4=1569485876.490932 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
### SET
###   @1=3 /* INT meta=0 nullable=1 is_null=0 */
###   @2='胡轲' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */
###   @3=1569483560.290861 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
###   @4=2147483647.999999 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
### UPDATE `zsd`.`test`
### WHERE
###   @1=2 /* INT meta=0 nullable=1 is_null=0 */
###   @2='刘忠浩' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */
###   @3=1569483491.886821 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
###   @4=1569485876.490932 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
### SET
###   @1=2 /* INT meta=0 nullable=1 is_null=0 */
###   @2='刘忠浩' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */
###   @3=1569483491.886821 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
###   @4=2147483647.999999 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
### UPDATE `zsd`.`test`
### WHERE
###   @1=1 /* INT meta=0 nullable=1 is_null=0 */
###   @2='张盛东' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */
###   @3=1569483491.886821 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
###   @4=1569485876.490932 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
### SET
###   @1=1 /* INT meta=0 nullable=1 is_null=0 */
###   @2='张盛东' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */
###   @3=1569483491.886821 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
###   @4=2147483647.999999 /* TIMESTAMP(6) meta=6 nullable=0 is_null=0 */
COMMIT
/*!*/;
COMMIT
/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;

执行flashback恢复操作

目的:闪回数据库zsd中的test 表。

[mysql@oradb ~]$ mysqlbinlog /u01/data/binlog/mysql-bin.000003 -vv -d zsd -T test --start-datetime="2019-09-26 16:17:51" --flashback | mysql -uroot -predhat

[mysql@oradb ~]$ mysql -uroot -predhat
MariaDB [(none)]> use zsd;

Database changed
MariaDB [zsd]> select * from test;
+------+-----------+
| id   | name      |
+------+-----------+
|    1 | 张盛东    |
|    2 | 刘忠浩    |
|    3 | 胡轲      |
+------+-----------+
3 rows in set (0.000 sec)

MariaDB [zsd]> 

可以看到之前删除的三条数据，恢复了。

参考文献

https://mariadb.com/kb/en/library/flashback/