MySQL 5.0 Reference Manual  /  Storage Engines  /  The InnoDB Storage Engine

14.2 The InnoDB Storage Engine

Key Advantages of InnoDB

InnoDB is a high-reliability and high-performance storage engine for MySQL. Key advantages of InnoDB include:

  • Its design follows the ACID model, with transactions featuring commit, rollback, and crash-recovery capabilities to protect user data.

  • Row-level locking (without escalation to coarser granularity locks) and Oracle-style consistent reads increase multi-user concurrency and performance.

  • InnoDB tables arrange your data on disk to optimize common queries based on primary keys. Each InnoDB table has a primary key index called the clustered index that organizes the data to minimize I/O for primary key lookups.

  • To maintain data integrity, InnoDB also supports FOREIGN KEY referential-integrity constraints.

  • You can freely mix InnoDB tables with tables from other MySQL storage engines, even within the same statement. For example, you can use a join operation to combine data from InnoDB and MEMORY tables in a single query.

  • InnoDB has been designed for CPU efficiency and maximum performance when processing large data volumes.

To determine whether your server supports InnoDB use the SHOW ENGINES statement. See Section, “SHOW ENGINES Syntax”.

InnoDB Storage Engine Features

The InnoDB storage engine maintains its own buffer pool for caching data and indexes in main memory. InnoDB stores its tables and indexes in a tablespace, which may consist of several files (or raw disk partitions). This is different from, for example, MyISAM tables where each table is stored using separate files. InnoDB tables can be very large even on operating systems where file size is limited to 2GB.

The Windows Essentials installer makes InnoDB the MySQL default storage engine on Windows, if the server being installed supports InnoDB.

MySQL Enterprise Backup and InnoDB

The MySQL Enterprise Backup product lets you back up a running MySQL database, including InnoDB and MyISAM tables, with minimal disruption to operations while producing a consistent snapshot of the database. When MySQL Enterprise Backup is copying InnoDB tables, reads and writes to both InnoDB and MyISAM tables can continue. During the copying of MyISAM tables, reads (but not writes) to those tables are permitted. In addition, MySQL Enterprise Backup supports creating compressed backup files, and performing backups of subsets of InnoDB tables. In conjunction with MySQL’s binary log, users can perform point-in-time recovery. MySQL Enterprise Backup is commercially licensed. For a more complete description of MySQL Enterprise Backup, see Section 22.2, “MySQL Enterprise Backup Overview”.

Additional Resources

A forum dedicated to the InnoDB storage engine is available at

InnoDB is published under the same GNU GPL License Version 2 (of June 1991) as MySQL. For more information on MySQL licensing, see

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