对MYSQL数据库进行数据恢复

编程知识更新时间:2023-05-02 19:28:33

DBRECOVER FOR MYSQL是一个MySQL数据库(Innodb)恢复工具，在MySQL没有备份的情况下，针对实例崩溃，Inoodb字典损坏无法启动数据库实例，DROP DATABASE，DROP TABLE，TRUNCATE TABLE,DELETE TABLE，磁盘/文件系统损坏等场景恢复数据库数据。

支持版本覆盖MYSQL 5.1 到 MySQL 8.0(2020年5月），支持MYSQL 8.0的全新数据字典结构
支持INNODB存储引擎， MYISAM支持仍在开发中
支持各种故障导致的MYSQL实例崩溃下的数据恢复
恢复结果为MYSQLDUMP格式的SQL文件
支持对DELETE 操作的数据行恢复
支持对DROP TABLE, TRUNCATE TABLE 操作的表恢复
支持对DROP DataBase操作的数据库恢复
支持因磁盘故障/文件系统损坏等情况下的恢复
免费版支持每张表抽取1000行数据，每张表抽取100行被delete的数据
基于JAVA开发，支持Windows/Redhat/Centos/Ubuntu等操作系统
支持对FRM文件的恢复，将FRM文件解析为CREATE TABLE的SQL语句
支持对LOB/TEXT等大对象的恢复

具体支持恢复场景：

针对MySQL数据库无法打开的场景的恢复

此场景下用户尝试启动MySQL实例，但MySQL实例可能因数据库本身损坏而CRASH进程崩溃,相关报错可能如下：

InnoDB: Waiting for the background threads to start
InnoDB: Error: tablespace size stored in header is 3712 pages, but
InnoDB: the sum of data file sizes is only 3072 pages
InnoDB: Cannot start InnoDB. The tail of the system tablespace is
InnoDB: missing. Have you edited innodb_data_file_path in myf in an
InnoDB: inappropriate way, removing ibdata files from there?
InnoDB: You can set innodb_force_recovery=1 in myf to force
InnoDB: a startup if you are trying to recover a badly corrupt database.

InnoDB: Assertion failure in thread 3876 in file ha_innodb line 17352
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: http://dev.mysql/doc/refman/5.6/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.

InnoDB: Assertion failure in thread 140154354255616 in file trx0purge.c line 848
InnoDB: Failing assertion: purge_sys->purge_trx_no <= purge_sys->rseg->last_trx_no
InnoDB: We intentionally generate a memory trap.

InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery

[ERROR] InnoDB: Attempted to open a previously opened tablespace. Previous tablespace database/table uses space ID: 882 at filepath

[Note] InnoDB: Starting crash recovery.
[ERROR] InnoDB: Tablespace 11904 was not found at ./example_db/example1.ibd.
[ERROR] InnoDB: Set innodb_force_recovery=1 to ignore this and to permanently lose all changes to the tablespace.
[ERROR] InnoDB: Tablespace 11905 was not found at ./example_db/example2.ibd.
[ERROR] InnoDB: Cannot continue operation.

InnoDB: Error: space header page consists of zero bytes in data file ./ibdata1

InnoDB: Database page corruption on disk or a failed file read of page 660. A table cannot be properly queried with the SELECT statement - additional possible output: MariaDB [psa]> select * from db_example.misc;
ERROR 2006 (HY000): MySQL server has gone away No connection. Trying to reconnect...

针对drop database场景的恢复

mysql> drop database employees;
Query OK, 14 rows affected (0.16 sec)

针对drop table 及 truncate table 场景的恢复

以下恢复步骤即适用于drop table 也适用于 truncate table

mysql> select count(*) from employees.employees;

+----------+
| count(*) |
+----------+
|   300024 |
+----------+
1 row in set (0.09 sec)

mysql> select @@datadir;
+-----------+
| @@datadir |
+-----------+
| /m01/     |
+-----------+
1 row in set (0.00 sec)

mysql> drop table employees.employees;
ERROR 1217 (23000): Cannot delete or update a parent row: a foreign key constraint fails


mysql> SET FOREIGN_KEY_CHECKS=0;
Query OK, 0 rows affected (0.00 sec)

mysql> drop table employees.employees;
Query OK, 0 rows affected (0.02 sec)

针对delete table场景的恢复

mysql> use  employees;
Database changed

mysql> select count(*) from employees;
+----------+
| count(*) |
+----------+
|     1000 |
+----------+
1 row in set (0.00 sec)


mysql> delete from employees;


mysql> flush table employees with read lock;
Query OK, 0 rows affected (0.01 sec)