Thursday, April 7, 2011

Identifying and Resolving MySQL Database Corruption


For a MySQL database administrator, a database corruption error might sound as if “the disaster has occurred”. The administrator rattles off typical suspects and applies all his knowledge and experience to overcome the disaster. However, in most cases, the corruption remains inescapable and the result is – database unmountability or strange behaviour of database. In such situations, a complete online backup acts as a boon and allows the administrator to mount and access the database objects. But, the disastrous situation might continue if the administrator has not maintained any backup or the backup file gets corrupted. For such situations, it is advisable to opt for a third-party MySQL database recovery application that provides complete repair of corrupted MySQL database.

Some common error messages that help a MySQL database administrator to identify that his MySQL database is corrupted are listed below:
  • 126: Index file is crashed / Wrong file format
  • 127: Record file is crashed
  • 132: Old database file
  • 134: Record was already deleted (or record file crashed)
  • 135: No more room in record file
  • 136: No more room in index file
  • 141: Duplicate unique key or constraint on write or update
  • 144: Table is crashed and last repair failed
  • 145: Tables was marked as crashed and should be repaired
Cause:

Few common ways by which MySQL database corruption occurs are killing MySQLD process in between, improper system shutdown, MySQL bug, and hardware failure.

Resolution:

To overcome the above error messages, the administrator needs to follow the below steps:
  • Run CHECK TABLE command to identify the level of corruption.
  • Run REPAIR TABLE command to repair the corrupt table.
In case the above steps fail to repair the database, then the user needs to find a good third-party MySQL repair application.

MySQL database repair tool information:

A MySQL recovery software is a permanent solution to repair corrupted MySQL database. The utility not only repairs and recovers all MySQL database components, but also restores them at user-specified location. The MySQL repair tool is easy understandable and does not require any prior technical knowledge.

Applied for:
MySQL 5.x

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