当我们忘记做全量备份时,并且没有开启binlog,并执行了deletefromsbtest;数据全部丢失,要想恢复是很有难度的。今天,利用PerconaDataRecoveryToolforInnoDB工
当我们忘记做全量备份时,并且没有开启binlog,并执行了
delete from sbtest;数据全部丢失,要想恢复是很有难度的。
今天,利用Percona Data Recovery Tool for InnoDB工具(仅支持InnoDB,MyISAM不支持),可以找回被删除的数据。
原理:在InnoDB引擎,delete删除操作,,不是真正的删除物理文件上的行,而是增加一个删除的标记,我们都用过WORD吧?在修改字体的时候,有一个删除线的标记,如《MySQL 管理之道》,该工具利用这个特性,找回那些标注了删除线的数据,并存入到一个文本里,然后通过load data命令,批量插入到表里。
注:truncate不能恢复(truncate是直接清空数据行,并不是添加删除标记,你可以通过查看物理文件,执行了truncate操作,ibd文件变小,而执行了delete操作,ibd文件还跟之前的一样大),drop不能恢复(数据文件都没了,还怎么恢复?)。
一、安装Percona Data Recovery Tool for InnoDB工具
# wget https://launchpad.net/percona-data-recovery-tool-for-innodb/trunk/release-0.5/+download/percona-data-recovery-tool-for-innodb-0.5.tar.gz
二、全表删除sbtest表
delete from sbtest;三、恢复
1、提取ibd物理文件,按照每页16K,单独存放。
在这里,0-28是sbtest表的主键(id),0-29是sbtest表的索引(k)。记住这个目录数字,后面我们需要通过这个目录恢复数据。
2、生成表结构
# cd percona-data-recovery-tool-for-innodb-0.5/ # ./create_defs.pl --host localhost --port 3306 --user root --password 123456 --db test --table sbtest > include/table_defs.h-- host 主机地址
-- port 端口
-- user 用户名
-- password 密码
-- db 数据库名
-- table 表名
3、再次执行make编译命令
# cd percona-data-recovery-tool-for-innodb-0.5/ # make4、恢复删除的数据
# cd percona-data-recovery-tool-for-innodb-0.5/ # ./constraints_parser -D -5 -f pages-1410414511/FIL_PAGE_INDEX/0-28/ > /tmp/sbtest.txt-D 恢复删除的行
-5 表的文件格式,默认是Compact
(不清楚的朋友,可以用show table status命令查看)
总结:
通过上述方法,顺利的完成了delete数据恢复。在数据被删除后,切记要备份ibd数据文件,一定不要覆盖,否则都是不能完成修复的。目前该工具不支持字符串set类型。
本文出自 “贺春旸的技术专栏” 博客,请务必保留此出处

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