MySQL模拟Oralce闪回操作
在前面的文章中我们介绍了MySQL误操作后数据恢复(update,delete忘加where条件),大概操作是通过sed命令把binlog中相关SQL误操作给逆向回来，然后导入SQL文件来恢复错误操作，sed相关命令也比较复杂。如果没有正则基础的同学肯定搞不清楚在干嘛。今天无意中发现淘宝的大神（翻译高性能mysql第三版的作者之一）开发了一个补丁，该补丁能够模拟Oracle的闪回操作，这样以来我们的MySQL也可以实现闪回咯。真是给力。注意：同样binlog格式需要是ROW
项目主页：http://mysql.taobao.org/index.php/Patch_source_code#Add_flashback_feature_for_mysqlbinlog
测试过程
1.给mysql打补丁，该补丁是针对mysql 5.5.18的版本，我测试的mysql 5.5.25版本也可以。（也可以使用我编译好了的，64位平台下的，在文中最后会有下载地址）
wget http://mysql.taobao.org/images/0/0f/5.5.18_flashback.diff cd /usr/local/src/mysql-5.5.25a/ patch -p0 < /root/5.5.18_flashback.diff cmake -DCMAKE_INSTALL_PREFIX=/usr/local/mysql make && make install
2.检查补丁是否应用成功，如果mysqlbinlog命令多了-B选项，那么就ok了。
[root@yayun-mysql-server ~]# mysqlbinlog --help | grep '\-B' -B, --flashback Flashback data to start_postition or start_datetime. [root@yayun-mysql-server ~]#
3.模拟误操作（update忘记加where条件）
(root@yayun-mysql-server) [test]> select * from tb1; +------+--------+ | id | name | +------+--------+ | 1 | yayun | | 2 | atlas | | 3 | dyy | | 4 | nginx | | 5 | apache | +------+--------+ 5 rows in set (0.00 sec) (root@yayun-mysql-server) [test]> update tb1 set name='yayun'; Query OK, 4 rows affected (0.03 sec) Rows matched: 5 Changed: 4 Warnings: 0 (root@yayun-mysql-server) [test]> select * from tb1; +------+-------+ | id | name | +------+-------+ | 1 | yayun | | 2 | yayun | | 3 | yayun | | 4 | yayun | | 5 | yayun | +------+-------+ 5 rows in set (0.00 sec) (root@yayun-mysql-server) [test]>
4.开始恢复
（1）首先需要找出错误的操作语句以及position点。
(root@yayun-mysql-server) [test]> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000023 | 364 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec) (root@yayun-mysql-server) [test]>
可见现在正在使用的是mysql-bin.000023这个binlog
[root@yayun-mysql-server mysql]# mysqlbinlog -vv mysql-bin.000023 |egrep -i -C 20 'update|tb1' # Warning: this binlog is either in use or was not closed properly. BINLOG ' RgZoUw8BAAAAZwAAAGsAAAABAAQANS41LjI1YS1sb2cAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAVAAEGggAAAAICAgCAA== '/*!*/; # at 107 #140506 5:45:21 server id 1 end_log_pos 175 Query thread_id=3 exec_time=0 error_code=0 SET TIMESTAMP=1399326321/*!*/; SET @@session.pseudo_thread_id=3/*!*/; SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/; SET @@session.sql_mode=0/*!*/; SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/; /*!\C utf8 *//*!*/; SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=33/*!*/; SET @@session.lc_time_names=0/*!*/; SET @@session.collation_database=DEFAULT/*!*/; BEGIN /*!*/; # at 175 # at 220 #140506 5:45:21 server id 1 end_log_pos 220 Table_map: `test`.`tb1` mapped to number 35 #140506 5:45:21 server id 1 end_log_pos 337 Update_rows: table id 35 flags: STMT_END_F BINLOG ' cQZoUxMBAAAALQAAANwAAAAAACMAAAAAAAEABHRlc3QAA3RiMQACAw8CPAAD cQZoUxgBAAAAdQAAAFEBAAAAACMAAAAAAAEAAv///AIAAAAFYXRsYXP8AgAAAAV5YXl1bvwDAAAA A2R5efwDAAAABXlheXVu/AQAAAAFbmdpbnj8BAAAAAV5YXl1bvwFAAAABmFwYWNoZfwFAAAABXlh eXVu '/*!*/; ### UPDATE test.tb1 ### WHERE ### @1=2 /* INT meta=0 nullable=1 is_null=0 */ ### @2='atlas' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */ ### SET ### @1=2 /* INT meta=0 nullable=1 is_null=0 */ ### @2='yayun' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */ ### UPDATE test.tb1 ### WHERE ### @1=3 /* INT meta=0 nullable=1 is_null=0 */ ### @2='dyy' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */ ### SET ### @1=3 /* INT meta=0 nullable=1 is_null=0 */ ### @2='yayun' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */ ### UPDATE test.tb1 ### WHERE ### @1=4 /* INT meta=0 nullable=1 is_null=0 */ ### @2='nginx' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */ ### SET ### @1=4 /* INT meta=0 nullable=1 is_null=0 */ ### @2='yayun' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */ ### UPDATE test.tb1 ### WHERE ### @1=5 /* INT meta=0 nullable=1 is_null=0 */ ### @2='apache' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */ ### SET ### @1=5 /* INT meta=0 nullable=1 is_null=0 */ ### @2='yayun' /* VARSTRING(60) meta=60 nullable=1 is_null=0 */ # at 337 #140506 5:45:21 server id 1 end_log_pos 364 Xid = 40 COMMIT/*!*/; DELIMITER ; # End of log file ROLLBACK /* added by mysqlbinlog */; /*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
开始的起点以107为准，因为107下面紧跟着BEGIN，结束的点以end_log_pos 337下一个点为准.
[root@yayun-mysql-server mysql]# mysqlbinlog -vv --start-position=337 mysql-bin.000023 /*!40019 SET @@session.max_insert_delayed_threads=0*/; /*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/; DELIMITER /*!*/; # at 4 #140506 5:44:38 server id 1 end_log_pos 107 Start: binlog v 4, server v 5.5.25a-log created 140506 5:44:38 # Warning: this binlog is either in use or was not closed properly. BINLOG ' RgZoUw8BAAAAZwAAAGsAAAABAAQANS41LjI1YS1sb2cAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAVAAEGggAAAAICAgCAA== '/*!*/; # at 337 #140506 5:45:21 server id 1 end_log_pos 364 Xid = 40 COMMIT/*!*/; DELIMITER ; # End of log file ROLLBACK /* added by mysqlbinlog */; /*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/; [root@yayun-mysql-server mysql]#
上面蓝色字体显示的很清楚了，那么结束的点就是364，因为下面紧跟着COMMIT。现在我们已经找到了日志开始起点为107，结束点为364，下面开始恢复。
[root@yayun-mysql-server mysql]# mysqlbinlog -B -vv --start-position=107 --stop-position=364 mysql-bin.000023 | mysql [root@yayun-mysql-server mysql]#
检查是否恢复成功：
(root@yayun-mysql-server) [test]> select * from tb1; +------+--------+ | id | name | +------+--------+ | 1 | yayun | | 2 | atlas | | 3 | dyy | | 4 | nginx | | 5 | apache | +------+--------+ 5 rows in set (0.00 sec) (root@yayun-mysql-server) [test]>
可见数据已经成功恢复。其实原理和我们前面通过sed操作binlog进行恢复是一样的。只是这个更简单。对于delete忘记添加where条件，恢复方法是一样的。这里不再重复。
总结:
binlog格式非常重要，无论是数据恢复还是主从复制，ROW格式都非常的给力。当然也有缺点，复制会占用过多带宽，消耗大量磁盘空间。
已经应用补丁的mysqlbinlog下载地址（64位平台，直接替换原来的即可）
