This topic describes the quotas and limits for ApsaraDB RDS for PostgreSQL. Before you create an ApsaraDB RDS for PostgreSQL instance, make sure that you understand the quotas and limits. This way, you can ensure the stability and security of the created RDS instance.

Quotas for ApsaraDB RDS for PostgreSQL

Item Quota Description
Storage capacity
  • RDS instance with local SSDs: up to 6,000 GB.
  • RDS instances with standard SSDs: up to 6,000 GB.
  • RDS instances with Enhanced SSDs (ESSDs): up to 32,000 GB.
The storage capacity of an RDS instance that is equipped with local SSDs varies based on the instance type. This limit does not apply to RDS instances that are equipped with standard SSDs or ESSDs. For more information, see Primary ApsaraDB RDS instance types.
Number of connections Up to 76,800. The number of connections that can be established to an RDS instance varies based on the instance type. For more information, see Primary ApsaraDB RDS instance types.
IOPS None.
Number of security groups Up to 10.
  • You must configure security groups for your RDS instance to allow the Elastic Compute Service (ECS) instances that belong to the security groups to communicate with the RDS instance.
  • You can configure only a security group that has the same network type as your RDS instance. In this case, the network types of your RDS instance and the security group that you want to configure must both be Virtual Private Cloud (VPC) or classic network.
Number of IP address whitelists Up to 50. None.
Number of root accounts Root accounts are not supported. ApsaraDB RDS for PostgreSQL does not provide superuser accounts.
Number of privileged accounts
  • RDS instances with local SSDs: Only one privileged account can be created for each RDS instance.
  • RDS instances with standard SSDs or ESSDs: Multiple privileged accounts can be created for each RDS instance.
  • You can create and manage privileged accounts by using the ApsaraDB RDS console or the ApsaraDB RDS API.
  • A privileged account has the permissions to disconnect all the standard accounts of the RDS instance on which the privileged account is created.
Number of standard accounts
  • RDS instances with local SSDs: Standard accounts are not supported.
  • RDS instances with standard SSDs or ESSDs: Multiple standard accounts can be created for each RDS instance.
  • You can create and manage standard accounts by using the ApsaraDB RDS console, ApsaraDB RDS API, or SQL statements.
  • You must manually grant the permissions on specific databases to each standard account.
  • A standard account does not have the permissions to create, manage, or disconnect the other accounts of the RDS instance on which the standard account is created.
Number of databases Unlimited. None.
Number of read-only instances for a primary instance
  • RDS instances with local SSDs: up to 5.
  • RDS instances with standard SSDs or ESSDs: up to 32.
  • Read-only RDS instances can be created for an RDS instance only when the RDS instance is a dedicated primary instance that is equipped with local SSDs and provides at least 8 cores and 32 GB of memory.
  • Read-only instances can be created only for primary RDS instances that run PostgreSQL 10 or later.
  • A read-only RDS instance with standard SSDs or ESSDs runs in a single-node architecture. In this architecture, no secondary RDS instance is provided as a standby for the read-only RDS instance.
  • The read-only RDS instances that you create must reside in the same region as the primary RDS instance to which these read-only RDS instances are attached.
Number of tags Up to 20. The keys of tags that are added to an RDS instance must be unique. You can add tags to a maximum of 50 RDS instances at a time.
Free quota for backup storage
  • RDS instances with local SSDs: Free quota for the storage of physical backup files = 50% × Purchased storage capacity.
  • RDS instances with standard SSDs or ESSDs: Free quota for the storage of snapshot backup files = 200% × Purchased storage capacity.
RDS instances that are equipped with standard SSDS or ESSDs support only snapshot backups. RDS instances that are equipped with local SSDs support only physical backups. If your backup usage exceeds the free quota, you are charged additional fees. You can calculate your excess backup storage based on the following formula: Excess backup storage usage = Size of data backup files + Size of log backup files - Free quota. Unit: GB. The result is rounded up to the next integer.

Limits for ApsaraDB RDS for PostgreSQL

Item Description
Instance name The name must be 2 to 255 characters in length, and can contain letters, digits, underscores (_), and hyphens (-). The name must start with a letter.
Username
The username of an account must meet the following requirements:
  • The username must be 2 to 16 characters in length.
  • The username can contain lowercase letters, digits, and underscores (_).
  • The username must start with a letter and end with a letter or digit.
  • The username must be unique.
  • The username cannot contain reserved keywords.
Password
The password of an account must meet the following requirements.
  • The password must be 8 to 32 characters in length.
  • The password must contain at least three of the following character types: uppercase letters, lowercase letters, digits, and special characters.
  • The password can contain any of the following characters: !@#$%^&*()_+-=
Port By default, an RDS instance is connected over port 1921. You can change the port number based on your business requirements.
Public endpoint You must manually apply for a public endpoint.
Database replication ApsaraDB RDS for PostgreSQL provides a primary/secondary replication architecture in all RDS editions except the Basic Edition. In this architecture, a secondary instance is provided as a standby. Secondary RDS instances are invisible to you and cannot be accessed by your applications.
Instance restart You must restart an RDS instance by using the ApsaraDB RDS console or the ApsaraDB RDS API.
Disk encryption You can enable disk encryption for an RDS instance only when you purchase the instance. Disk encryption cannot be disabled after it is enabled.
Number of parameter reconfiguration records None.
Retention period of parameter reconfiguration records None.
Number of instance backup records None.
Backup retention period The default retention period is 7 days, and the maximum retention period is 730 days.
Number of error log records None.
Error log retention period 30 days.
Number of detailed slow log records None.
Retention period of detailed slow log records. 30 days.

Limits on SQL commands

The limits on SQL commands in ApsaraDB RDS for PostgreSQL are the same as the limits on SQL commands in open source PostgreSQL. For more information, see PostgreSQL command reference.