InnoDB is a general-purpose storage engine that
balances high reliability and high performance. In MySQL
InnoDB is the default MySQL
storage engine. Unless you have configured a different default
storage engine, issuing a
TABLE statement without an
clause creates an
Its DML operations follow the ACID model, with transactions featuring commit, rollback, and crash-recovery capabilities to protect user data. See Section 15.2, “InnoDB and the ACID Model”.
Row-level locking and Oracle-style consistent reads increase multi-user concurrency and performance. See Section 15.7, “InnoDB Locking and Transaction Model”.
InnoDBtables arrange your data on disk to optimize queries based on primary keys. Each
InnoDBtable has a primary key index called the clustered index that organizes the data to minimize I/O for primary key lookups. See Section 126.96.36.199, “Clustered and Secondary Indexes”.
To maintain data integrity,
FOREIGN KEYconstraints. With foreign keys, inserts, updates, and deletes are checked to ensure they do not result in inconsistencies across related tables. See Section 188.8.131.52, “FOREIGN KEY Constraints”.
Table 15.1 InnoDB Storage Engine Features
|Backup/point-in-time recovery (Implemented in the server, rather than in the storage engine.)||Yes|
|Cluster database support||No|
|Encrypted data||Yes (Implemented in the server via encryption functions; In MySQL 5.7 and later, data-at-rest encryption is supported.)|
|Foreign key support||Yes|
|Full-text search indexes||Yes (Support for FULLTEXT indexes is available in MySQL 5.6 and later.)|
|Geospatial data type support||Yes|
|Geospatial indexing support||Yes (Support for geospatial indexing is available in MySQL 5.7 and later.)|
|Hash indexes||No (InnoDB utilizes hash indexes internally for its Adaptive Hash Index feature.)|
|Replication support (Implemented in the server, rather than in the storage engine.)||Yes|
|Update statistics for data dictionary||Yes|
To compare the features of
InnoDB with other
storage engines provided with MySQL, see the Storage
Engine Features table in
Chapter 16, Alternative Storage Engines.
For information about
InnoDB enhancements and new
features, refer to:
InnoDB-related terms and definitions, see the MySQL Glossary.
For a forum dedicated to the
InnoDBstorage engine, see MySQL Forums::InnoDB.
InnoDBis published under the same GNU GPL License Version 2 (of June 1991) as MySQL. For more information on MySQL licensing, see http://www.mysql.com/company/legal/licensing/.