InnoDB combines the familiar reliability and performance of the InnoDB storage engine, with new performance and usability enhancements. InnoDB includes all the features that were part of the InnoDB Plugin for MySQL 5.1, plus new features specific to MySQL 5.5 and higher.
Beginning with MySQL version 5.5, InnoDB is the default storage
engine, rather than MyISAM. Issuing the
TABLE statement without an
clause creates an
Key advantages of
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.
To maintain data integrity,
FOREIGN KEYconstraints. With foreign keys, inserts, updates, and deletes are checked to ensure they do not result in inconsistencies across different tables.
You can freely mix
InnoDBtables with tables from other MySQL storage engines, even within the same statement. For example, you can use a join operation to combine data from
MEMORYtables in a single query.
InnoDBhas been designed for CPU efficiency and maximum performance when processing large data volumes.
InnoDBstorage engine maintains its own buffer pool for caching data and indexes in main memory.
InnoDBtables can handle large quantities of data, even on operating systems where file size is limited to 2GB.
Table 14.1 InnoDB Storage Engine Features
|Storage limits||64TB||Transactions||Yes||Locking granularity||Row|
|MVCC||Yes||Geospatial data type support||Yes||Geospatial indexing support||Yes[a]|
|B-tree indexes||Yes||T-tree indexes||No||Hash indexes||No[b]|
|Full-text search indexes||Yes[c]||Clustered indexes||Yes||Data caches||Yes|
|Index caches||Yes||Compressed data||Yes[d]||Encrypted data[e]||Yes|
|Cluster database support||No||Replication support[f]||Yes||Foreign key support||Yes|
|Backup / point-in-time recovery[g]||Yes||Query cache support||Yes||Update statistics for data dictionary||Yes|
[a] InnoDB support for geospatial indexing is available in MySQL 5.7.5 and higher.
[b] InnoDB utilizes hash indexes internally for its Adaptive Hash Index feature.
[c] InnoDB support for FULLTEXT indexes is available in MySQL 5.6.4 and higher.
[d] Compressed InnoDB tables require the InnoDB Barracuda file format.
[e] Implemented in the server (via encryption functions). Data-at-rest tablespace encryption is available in MySQL 5.7 and higher.
[f] Implemented in the server, rather than in the storage engine.
[g] Implemented in the server, rather than in the storage engine.
To compare the features of
InnoDB with other
storage engines provided with MySQL, see the Storage
Engine Features table in
Chapter 15, Alternative Storage Engines.
The InnoDB storage engine in MySQL 5.5 releases
includes a number performance improvements that in MySQL 5.1 were
only available by installing the InnoDB Plugin. This latest InnoDB
offers new features, improved performance and scalability, enhanced
reliability and new capabilities for flexibility and ease of use.
Among the top features are Fast Index Creation, table and index
compression, file format management, new
INFORMATION_SCHEMA tables, capacity tuning,
multiple background I/O threads, multiple buffer pools, and group
commit. For more information about these features, see
Section 14.1.1, “Features of the InnoDB Storage Engine”.
For additional information about
enhancements and new features in MySQL 5.5, also refer
InnoDB-related terms and definitions, see MySQL Glossary.
A forum dedicated to the
InnoDBstorage engine is available here: 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/.