To ensure instance stability and security, ApsaraDB RDS for MySQL has some service limits.

Limits of other database engines are listed as follows:

The following tables lists the limits of ApsaraDB RDS for MySQL.

Item Limit description
Instance parameters Instance parameters can be modified through the RDS console or API operations. Due to security and stability considerations, only specific parameters can be modified. For more information, see Use the console to set parameters.
Root permissions of databases The root or system administrator permissions are not provided.
Database backup
  • Logical backup can be performed through the command line interface (CLI) or graphical user interface (GUI).
  • Physical backup can only be performed through the RDS console or API operations.
Database restoration
  • Logical restoration can be performed through the CLI or GUI.
  • Physical restoration can only be performed through the RDS console or API operations.
ApsaraDB RDS for MySQL storage engine Only InnoDB is supported.
  • For performance and security considerations, we recommend that you use the InnoDB storage engine.
  • The TokuDB engine is not supported. ApsaraDB RDS for MySQL has terminated its support for the TokuDB engine since August 1, 2019 because TokuDB is no longer supported by Percona and bugs may cause business losses in extreme cases. For more information about how to switch to an available engine, see [Notice] The storage engine was switched from TokuDB to InnoDB.
  • The MyISAM engine is not supported due to inherent defects that may cause data loss. If you create a MyISAM engine table, it will be automatically converted into an InnoDB engine table. For more information, see Why does RDS MySQL not support the MyISAM engine?
  • The Memory engine is not supported. If you create Memory engine tables, they are automatically converted to InnoDB engine tables.
Database replication ApsaraDB RDS for MySQL provides a primary/secondary replication architecture (except in the Basic Edition). The secondary instance in the architecture is hidden and cannot access your applications.
Instance restart Instances must be restarted through the RDS console or API operations.
Network settings If a MySQL 5.5 or 5.6 instance is in the classic network and the database proxy mode is enabled for it, you are not allowed to enable net.ipv4.tcp_timestamps in SNAT mode.
Storage space

If the storage space usage for an instance is abnormally high, the system will lock the instance to prevent data loss that may occur due to incorrect operations. You can unlock the instance by upgrading the instance specifications.

Help information You cannot query help topic details because the mysql.help_topic table is empty.