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Tag: innodb dictionary

Presenting TwinDB Data Recovery Toolkit on #SFMySQL Meetup

On 5 November, I’ll be speaking at #SFMySQL Meetup about Data Recovery Software for MySQL Add Slipped & DROP’d your TABLE? Recover w/TwinDB’s Undrop for InnoDB toolkit to your calendar. There will be a demo and if you want to try to undrop a table yourself bring in a laptop with Linux. Download the latest […]

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Temporary table naming scheme in 5.6 and before

Benchmarking is a popular topic. People love drawing graphs as much as watching how X is 10% faster than Y; there must be something special in measurements. For a DBA, however, more tangible improvements come from less popular area of database maintenance. While MariaDB spreads FUD around InnoDB (nonetheless still uses it) I have to […]

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Resolving ERROR 1050 42S01 at line 1 Table already exists

When ALTER TABLE crashes MySQL server it leaves orphaned records in InnoDB dictionary. It is annoying because next time you run the same ALTER TABLE query it will fail with error:

The post explains why it happens and how to fix it. When you run ALTER table InnoDB follows the plan: Block the original […]

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Recover Table Structure From InnoDB Dictionary

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

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InnoDB dictionary

Why Does InnoDB Need Dictionary 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 tables by their names, InnoDB works with integer identifiers. The dictionary stores correspondence between table name and index_id. The […]

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