Monday, September 22, 2014

Tips to Recover Data from Corrupt MySQL Database

Stellar Repair for MySQL can help in recovery of data from corrupt or damaged MySQL database. In this article I will show how to repair corrupt or damaged MySQL database’ file when it becomes corrupt.

Corruption in MySQL database can happen due to any uncertain reasons. Hardware problem, virus attach, power failure, bugs in MySQL itself, automatic system shutdown are the most common causes for MySQL database corruption. A bad hard drive can write garbage value in the MySQL database and then MySQL reports error messages.

“Cannot load from mysql.proc. The table is probably corrupted”
“MySQL error code 145= Table was marked as crashed and should be repaired”


There are several ways available to recover data from corrupt or damaged MySQL database:

InnoDB Force Recovery

It helps in recovery of data from corrupt MySQL database. By default, 0 is the value of innodb force recovery and database administrator can change it from 1 to 6. A higher value of InnoDB force recovery includes all the functionalities of lower values. For Example, 6 includes all the functionalities of values 5, 4, 3, 2, & 1.

Note: Only use InnoDB force recovery value greater than 0 when there is an emergency situation and make a backup copy of your database before trying it. Backup will help you in recreating the database when needed.

Steps to use InnoDB force recovery:
  • First of all stop MySQL server (mysqld) and copy all the files from /var/lib/mysql.
  • Use innodb-force-recovery to mysqld.
[mysqld]
Innodb_force_recovery=5
  • Start the MySQL server.
  • Dump all the databases.
  • Now restore the database from dump.
Restore from Backup

If the above method does not help then try tested & updated backup. It is the ideal solution to recover database from corrupt database file. Go with the next method, if backup is not available or too old.

Stellar Repair for MySQL

The only remaining method is use Stellar Repair for MySQL software if above solutions fail to restore the database from corrupt MySQL InnoDB database.

Stellar Repair for MySQL is developed by Stellar data recovery and the current version is 6.0. It is available for Windows as well as for Linux but you need to copy your MySQL database from Linux machine to Windows machine and run repair operation over there then after restore the database from Windows machine to Linux machine.

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