There are times when you might want to use the InnoDB Plugin with a given database, and then downgrade to the built-in InnoDB in MySQL. One reason to do this is because you want to take advantage of a new InnoDB storage engine feature (such as “Fast Index Creation”), but revert to the standard built-in InnoDB in MySQL for production operation.

If you have created new tables using the InnoDB storage engine, you might need to convert them to a format that the built-in InnoDB in MySQL can read. Specifically, if you have created tables that use ROW_FORMAT=COMPRESSED or ROW_FORMAT=DYNAMIC you must convert them to a different format, if you plan to access these tables with the built-in InnoDB in MySQL. If you do not do so, anomalous results may occur.

Although InnoDB checks the format of tables and database files (specifically *.ibd files) for compatibility, it is unable to start if there are buffered changes for “too new format” tables in the redo log or in the system tablespace. Thus it is important to carefully follow these procedures when downgrading from the InnoDB storage engine to the built-in InnoDB in MySQL, version 5.1.

This chapter describes the downgrade scenario, and the steps you should follow to ensure correct processing of your database.