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RDS for MySQL

Feature

Automatically converting storage engine to InnoDB

This topic describes the feature in RDS for MySQL that automatically converts MyISAM, Memory, and Archive storage engines to the InnoDB storage engine.

Background

RDS for MySQL supports the InnoDB storage engine by default but does not support the MyISAM, Memory, or Archive storage engines. To facilitate database migration or upgrades, you can automatically convert MyISAM, Memory, and Archive storage engines to the InnoDB storage engine.

Supported version

MySQL 5.7 version, and the kernel minor version is MySQL 5.7.32_20250415 and above.

MySQL 8.0 version, and the kernel minor version is MySQL 8.0.32_20250415 and above.

MySQL 8.4 version, and the kernel minor version is MySQL 8.4.7_20260415 and above.

tip

You can view the kernel minor version of an instance by Viewing instance information. If the kernel minor version of your instance is not within the supported range, you can Manually upgrading the instance kernel minor version.

Instructions

When a user creates a table and specifies the storage engine as MyISAM, Memory, or Archive, the storage engine is automatically converted to InnoDB.

mysql> create table t(a int) engine = myisam;
Query OK, 0 rows affected, 2 warnings (0.14 sec)

mysql> show create table t\G
*************************** 1. row ***************************
Table: t
Create Table: CREATE TABLE `t` (
`a` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

If a user creates a table without specifying a storage engine but sets the default engine to MyISAM, Memory, or Archive (for example, default_storage_engine = 'myisam'), the storage engine is also automatically converted to InnoDB.

mysql> set global default_storage_engine = 'myisam';
Query OK, 0 rows affected (0.00 sec)

mysql> create table t(a int);
Query OK, 0 rows affected (0.12 sec)

mysql> show create table t\G
*************************** 1. row ***************************
Table: t
Create Table: CREATE TABLE `t` (
`a` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

To disable the automatic conversion feature, set the value of the loose_convert_disabled_engines_to_innodb parameter to off. For detailed information on modifying parameters, please refer to Modifying parameters.

Limitations

The MyISAM engine supports composite primary keys that include auto-increment columns, while the InnoDB engine does not. Therefore, an error is reported when creating a table after it has been converted from MyISAM to InnoDB. The error message is as follows:

We recommend that you create an index for the auto-increment column to use composite primary keys that include an auto-increment column in the InnoDB engine. Example as follows:

The modification is as follows. The table is created successfully with the InnoDB storage engine:

Last updated: 2026.05.28 15:17:49