Help Center/ Relational Database Service/ User Guide (Ally Region)/ Service Overview/ Constraints/ RDS for MySQL Constraints
Updated on 2026-04-24 GMT+08:00
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RDS for MySQL Constraints

The following tables list the constraints designed to ensure the stability and security of RDS for MySQL.

Specifications and Performance

Table 1 Specifications

Item

Specifications

Storage space
  • Cloud SSD: 40 GB to 4,000 GB
  • Extreme SSD: 40 GB to 4,000 GB

Connections

A maximum of 100,000

IOPS
  • Cloud SSD: a maximum of 50,000
  • Extreme SSD: a maximum of 128,000

Quotas

Table 2 Quotas

Item

Constraints

Description

Read replica

A maximum of 10 read replicas can be created for a DB instance.

For more information, see Introducing Read Replicas.

Tags

A maximum of 20 tags can be added for a DB instance.

For more information, see RDS for MySQL Tags.

Free backup space

RDS provides free backup space of the same size as your purchased storage space.

Free backup space is provided after you purchase storage space. For more information, see How Is RDS Backup Data Billed?.

Retention period of automated backups

The default value is 7 days. The value ranges from 1 to 732 days.

For more information, see Configuring Same-Region Backup Policies.

Log retention period
  • Error log details: 30 days
  • Slow query log details: 30 days
  • Original slow query logs: 30 days
  • Slow query log statistics: 30 days
  • Failover/switchover logs: 30 days
  • SQL audit logs: The default value is 7 days. The value ranges from 1 to 732 days.

For more information, see Log Management.

Naming

Table 3 Naming

Item

Constraints

Instance name
  • 4 to 64 characters long
  • Must start with a letter. Only letters (case sensitive), digits, hyphens (-), and underscores (_) are allowed.

Database name
  • 1 to 64 characters long
  • Only letters, digits, hyphens (-), and underscores (_) are allowed. The total number of hyphens (-) cannot exceed 10.

Account name
  • RDS for MySQL 5.6: The account name must be 1 to 16 characters long. Only letters, digits, hyphens (-), and underscores (_) are allowed.
  • RDS for MySQL 5.7 and 8.0: The account name must be 1 to 32 characters long. Only letters, digits, hyphens (-), and underscores (_) are allowed.

Backup name
  • 4 to 64 characters long
  • Must start with a letter. Only letters (case sensitive), digits, hyphens (-), and underscores (_) are allowed.

Parameter template name
  • 1 to 64 characters long
  • Only letters (case sensitive), digits, hyphens (-), underscores (_), and periods (.) are allowed.

Security

Table 4 Security

Item

Constraints

root permissions

Only the administrator account root is provided on the instance creation page. For details about the supported permissions, see Root Permissions.

NOTE:

Running revoke, drop user, or rename user on root may cause service interruption. Exercise caution when running any of these statements.

root password
  • 8 to 32 characters long
  • Must contain at least three types of the following characters: uppercase letters, lowercase letters, digits, and special characters (~!@$#%^*-_=+?,()&.|).

For more information, see Resetting the Administrator Password.

Database port

1024 to 65535 (excluding 12017, 33071, and 33062, which are occupied by the RDS system)

For more information, see Changing a Database Port.

Disk encryption

If you enable disk encryption during instance creation, the disk encryption status and the key cannot be changed later.

For more information, see Configuring Disk Encryption.

VPC

The VPC where an RDS instance is located cannot be changed after the instance is created.

Security group
  • By default, you can create a maximum of 100 security groups in your cloud account.
  • By default, you can add up to 50 security group rules to a security group. For more information, see Configuring Security Group Rules.
  • One RDS DB instance can be associated with multiple security groups, and one security group can be associated with multiple RDS DB instances.
  • When creating a DB instance, you can select multiple security groups. For better network performance, select no more than five security groups. For more information, see Changing a Security Group.

System database

When you create an RDS for MySQL instance, the system automatically creates the following system databases for the instance. DML operations cannot be performed on system databases or system tables.

  • __recyclebin__ (8.0.32 and later)
  • information_schema
  • mysql
  • performance_schema
  • sys

System account

To provide O&M services, the system automatically creates system accounts when you create RDS for MySQL DB instances. These system accounts are unavailable to you.

  • rdsAdmin: a management account with the highest privileges. It is used to query and modify instance information, rectify faults, migrate data, and restore data.
  • rdsRepl: a replication account. It is used to synchronize data from a primary instance to its standby instance or read replicas.
  • rdsBackup: a backup account. It is used to back up data in the background.
  • rdsMetric: a metric monitoring account. It is used by watchdog to collect database status data.
  • rdsProxy: a proxy account. It is automatically created when Database Proxy is enabled and is used for authentication when a database is connected through a read/write splitting address.
  • rdsFillBinlog: a binlog synchronization account. If binlogs are not synchronized during a primary/standby switchover, this account is created to synchronize binlogs.

Instance parameter

To ensure optimal performance of RDS, you can modify parameters in the parameter template you created as needed.

For more information, see Suggestions on RDS for MySQL Parameter Tuning.

Instance Operations

Table 5 Instance operations

Item

Constraints

RDS for MySQL storage engine

Only the InnoDB storage engine is supported. MyISAM, FEDERATED, and MEMORY are not supported.

Instance deployment

ECSs where DB instances are deployed are not directly visible to you. You can only access the DB instances through IP addresses and database ports.

Primary/Standby replication

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 you and therefore you cannot access it directly.

Rebooting a DB instance

DB instances cannot be rebooted through commands. They must be rebooted through the RDS console.

Viewing backups

You can download automated and manual backups for local storage. To download a backup, you can use OBS Browser+, the current browser, or the download URL.

For more information, see Downloading a Full Backup.

Log management
  • RDS for MySQL logging is enabled by default and cannot be disabled.
  • RDS for MySQL enables binary logging by default and sets binlog_format to ROW.
  • Read replicas do not have backups and do not provide binlogs.

Recycle bin

RDS allows you to move deleted pay-per-use DB instances to the recycle bin. You can rebuild an instance that was deleted up to 7 days ago from the recycle bin.

Root Permissions

Table 6 Root permissions

Permission

Level

Description

Supported

Select

Table

Query permissions

Yes

Insert

Table

Insert permissions

Update

Table

Update permissions

Delete

Table

Delete permissions

Create

Database, table, or index

Permissions of creating databases, tables, or indexes

Drop

Database or table

Permissions of deleting databases or tables

Reload

Server management

Permission of running commands such as FLUSH-HOSTS, FLUSH-LOGS, FLUSH-PRIVILEGES, FLUSH-STATUS, FLUSH-TABLES, FLUSH-THREADS, REFRESH, and RELOAD

Process

Server management

Permissions of viewing processes

Grant

Database, table, or stored program

Permissions of granting access control

References

Database or table

Foreign key operation permissions

Index

Table

Index permissions

Alter

Table

Permissions of altering tables, such as adding fields or indexes

Show_db

Server management

Permissions of listing databases

Create_tmp_table

Server management

Permissions of creating temporary tables

Lock_tables

Server management

Permissions of locking tables

Execute

Stored procedure

Permissions of executing stored procedures

Repl_slave

Server management

Replication permissions

Repl_client

Server management

Replication permissions

Create_view

View

Permissions of creating views

Show_view

View

Permissions of showing views

Create_routine

Stored procedure

Permissions of creating stored procedures

Alter_routine

Stored procedure

Permissions of altering stored procedures

Create_user

Server management

Permissions of creating users

Event

Database

Permissions of event scheduler

Trigger

Database

Triggers

Super

Server management

Permissions of terminating threads

No

File

File on the server

Permissions of accessing files on database server nodes

No

Shutdown

Server management

Permissions of shutting down databases

Create_tablespace

Server management

Permissions of creating tablespaces

Parent topic: Constraints