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Category: MySQL Data Recovery

Recover Table Structure From InnoDB Dictionary

When a table gets dropped, MySQL removes the respective .frm file. This post explains how to recover the table structure if the table was dropped. You need the table structure to recover a dropped table from the InnoDB tablespace. The B+tree structure of the InnoDB index doesn’t contain any information about field types. MySQL needs […]

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Recovering A Corrupt MySQL Database

UPDATE: We announced online data recovery from corrupt databases. Check it out on https://recovery.twindb.com/ UPDATE (01/01/2017): We stopped further development of undrop-for-innodb and don’t support its open source versions anymore. The unDROP for InnoDB tool can be used to recover corrupt MySQL databases. In this post, we will show how to repair a MySQL database […]

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Repair Corrupted InnoDB Tables With Secondary Index Corruption

UPDATE: We announced online data recovery from corrupt databases. Check it out on https://recovery.twindb.com/ UPDATE (01/01/2017): We stopped further development of undrop-for-innodb and don’t support its open source versions anymore. InnoDB provides no means to repair corrupted table space. Once a table got corrupted, the only way to repair MySQL files is to start it […]

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Recovery After DROP TABLE, With Innodb_file_per_table ON

UPDATE (01/01/2017): We stopped further development of undrop-for-innodb and don’t support its open source versions anymore. Introduction In the previous post, we described a situation when the TwinDB recovery toolkit can be used to recover an accidentally dropped table with innodb_file_per_table=OFF. In this post, we’ll show how to recover MySQL tables or databases if innodb_file_per_table is ON. So, […]

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Recovery After DROP TABLE, With Innodb_file_per_table OFF

UPDATE (01/01/2017): We stopped further development of undrop-for-innodb and don’t support its open source versions anymore. Introduction Unfortunately, human mistakes are inevitable. That’s how life is. Wrong “DROP DATABASE” or “DROP TABLE” may destroy critical data on the MySQL server. Obviously, backups would help, however they’re not always available. This situation is frightening but not […]

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InnoDB Dictionary

Why Does InnoDB Need A Dictionary An InnoDB dictionary is a set of internal tables InnoDB uses to maintain various information about user tables. It serves as API between a human and the database. While the humans refer to tables by their names, InnoDB works with integer identifiers. The dictionary stores correspondence between table name […]

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