MySQL 5.5 Reference Manual Including MySQL NDB Cluster 7.2 Reference Guide

14.1 Introduction to InnoDB

InnoDB is a general-purpose storage engine that balances high reliability and high performance. Starting from MySQL 5.5.5, the default storage engine for new tables is InnoDB rather than MyISAM. Unless you have configured a different default storage engine, issuing a CREATE TABLE statement without an ENGINE= clause creates an InnoDB table. Given this change of default behavior, MySQL 5.5 might be a logical point to evaluate whether tables that use MyISAM could benefit from switching to InnoDB.

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.


The mysql and INFORMATION_SCHEMA databases that implement some of the MySQL internals still use MyISAM. In particular, you cannot switch the grant tables to use InnoDB.

Key Advantages of InnoDB

Table 14.1 InnoDB Storage Engine Features

Feature Support
B-tree indexes Yes
Backup/point-in-time recovery (Implemented in the server, rather than in the storage engine.) Yes
Cluster database support No
Clustered indexes Yes
Compressed data Yes
Data caches Yes
Encrypted data Yes (Implemented in the server via encryption functions; In MySQL 5.7 and later, data-at-rest tablespace encryption is supported.)
Foreign key support Yes
Full-text search indexes Yes (InnoDB support for FULLTEXT indexes is available in MySQL 5.6 and later.)
Geospatial data type support Yes
Geospatial indexing support Yes (InnoDB 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.)
Index caches Yes
Locking granularity Row
Replication support (Implemented in the server, rather than in the storage engine.) Yes
Storage limits 64TB
T-tree indexes No
Transactions 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 15, Alternative Storage Engines.

InnoDB Enhancements and New Features

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.

For information about InnoDB enhancements and new features, refer to:

Additional InnoDB Information and Resources