MySQL Constraints

Table 1 shows the constraints designed to ensure the stability and security of RDS for MySQL.

**Table 1** Function constraints
Function Item	Constraints
Database access	If public accessibility is not enabled, the RDS DB instance must be in the same VPC as the ECS. RDS read replicas must be created in the same subnet as the primary DB instance. The security group must allow access from the ECS. By default, RDS cannot be accessed through an ECS in a different security group. You need to add an inbound rule to the RDS security group. The default MySQL port is 3306. You can if you want to access MySQL through another port.
Deployment	ECSs in which DB instances are deployed are not visible to users. You can access the DB instances only through an IP address and a port number.
Database root permissions	Only the root user permissions are provided on the instance creation page.
Database parameter modification	Most parameters can be modified on the RDS console.
Data migration	Use MySQL CLI tools to migrate data by referring to Migrating Data to RDS for MySQL Using mysqldump.
MySQL storage engine	For details, see What Storage Engines Does the RDS for MySQL Support?
Database replication setup	RDS for MySQL uses a primary/standby dual-node replication cluster. You do not need to set up replication additionally. The standby DB instance is not visible to users and therefore you cannot access it directly.
Minor version upgrade	Currently, RDS for MySQL supports a maximum of 100,000 tables. If the number of tables is greater than 100,000, the minor version upgrade may fail.
DB instance reboot	RDS DB instances cannot be rebooted through commands. They must be rebooted through the RDS console.
RDS backup files	For details, see Downloading a Backup File.