This topic describes the limits of RDS MySQL. To guarantee stability and security, you must understand the limits.

The following table describes the limits of common actions and configurations in RDS MySQL.

Item Limit description
Parameter modification The RDS console or supported API actions must be used to modify database parameters. But For security parameters, some parameters cannot be modified. For more information, see Set parameters through the RDS console.
Database root permission The root and sa permissions are not provided.
Database backup
  • Supported CLIs or GUIs can be used for logical data backup.
  • For physical data backup, the RDS console or supported API actions must be used.
Database restoration
  • Supported CLIs or GUIs can be used for logical data restoration.
  • For physical data restoration, the RDS console or supported API actions must be used.
MySQL storage engine Currently only InnoDB is supported.
  • InnoDB is more secure and provides high performance.
  • TokuDB is not supported. Percona no longer supports TokuDB. As a result, a number of known issues in TokuDB cannot be resolved. These known issues may cause loss to your service in certain circumstances. Therefore, RDS MySQL has stoped supporting TokuDB since August 1st, 2019.
  • MyISAM is not supported due to its born defects that may cause data loss. If you create MyISAM engine tables, they are automatically converted into InnoDB engine tables. For more information, see Why does RDS for MySQL not support the MyISAM engine?
  • Memory is not supported. If you create Memory engine tables, they are automatically converted to InnoDB engine tables.
Database replication MySQL provides a dual-node cluster based on the master/slave replication architecture(except for the basic edition). The slave instance in the architecture is invisible to you, and your application cannot access to the slave instance directly.
Instance restart Instances must be restarted through the RDS console or supported API actions.
Network settings If a MySQL 5.5/5.6 instance is in a classic network and the database proxy mode is enabled for it, do not enable net.ipv4.tcp_timestamps in SNAT mode.
Storage space If the storage space usage for an RDS MySQL instance is abnormally high, the system locks the instance to prevent data loss that may occur due to misoperations. You can unlock the instance by upgrading the instance specifications.
Monitoring and alerting The MySQL5.7 High-availability Edition (with standard SSDs) does not support the alerting function.