This topic describes the quotas and limits on 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 your RDS instance.
Specifications and performance
Item | Specification | Description |
Storage capacity |
| The storage capacity of an RDS instance that uses local SSDs varies based on the instance type. This limit does not apply to RDS instances that use standard SSDs or ESSDs. For more information, see Primary ApsaraDB RDS instance types. |
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. |
Memory capacity |
| For RDS instances that use cloud disks, the memory includes the memory that is occupied by the underlying operating system and the memory that is occupied by the RDS-related management services. Therefore, the available memory of an RDS instance may be less than the memory capacity that is supported by the instance type. The following list describes the memory that is occupied by the underlying operating system and the memory that is occupied by the RDS-related management services:
|
Quotas
Item | Quota |
Read-only RDS instance | Read-only RDS instances are supported only for RDS instances that run PostgreSQL 10 or later. The read-only RDS instances that you create must reside in the same region as the primary RDS instance to which the read-only RDS instances are attached.
For more information about read-only RDS instances, see Overview of read-only ApsaraDB RDS for PostgreSQL instances. |
Tag | The key of a tag must be unique. You can add up to 20 tags to an RDS instance. You can add tags to up to 50 RDS instances at a time. For more information, see Add tags to ApsaraDB RDS instances. |
Free quota on backup storage | RDS instances that use cloud disks support only snapshot backups. RDS instances that use local disks support only physical backups. If your backup storage exceeds the free quota, you are charged for your excess backup storage. Your excess backup storage is calculated by using the following formula: Excess backup storage = Size of data backup files + Size of log backup files - Free quota. Unit: GB. The obtained result is rounded up to the next integer.
For more information, see Back up an ApsaraDB RDS for PostgreSQL instance. |
Backup retention period | The default retention period is 7 days, and the maximum retention period is 730 days. |
Retention period of error logs | The retention period is 30 days. For more information, see View logs. |
Retention period of slow log details | The retention period is 30 days. For more information, see View logs. |
Limits on names
Item | Description |
Instance name |
|
Username |
|
Database name |
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Limits on security
Item | Description |
Password | The password of an account must meet the following requirements:
|
Port | By default, an RDS instance is connected over port 5432. You can change the port number based on your business requirements. |
Instance parameter configuration | For security and stability purposes, some parameters cannot be modified. You can modify most of the instance parameters in the ApsaraDB RDS console or by calling the ApsaraDB RDS API. For more information, see Modify the parameters of an ApsaraDB RDS for PostgreSQL instance. |
Cloud disk encryption | You can enable cloud disk encryption for an RDS instance only when you purchase the instance. Cloud disk encryption cannot be disabled after it is enabled. For more information, see Configure the cloud disk encryption feature. |
Number of security groups | You can configure up to 10 security groups for an RDS instance.
For more information, see Configure a security group. |
Number of IP address whitelists | You can configure up to 50 IP address whitelists for an RDS instance. For more information about how to configure a whitelist, see Configure an IP whitelist. |
Root account | You cannot create root accounts. ApsaraDB RDS for PostgreSQL does not provide superuser accounts such as root accounts. |
Privileged account | You can create and manage privileged accounts in the ApsaraDB RDS console or by using the ApsaraDB RDS API. You can create multiple privileged accounts for an RDS instance. The privileged accounts of an RDS instance have the permissions to disconnect all standard accounts of the RDS instance. For more information, see Create an account. |
Standard account | You can create and manage standard accounts in the ApsaraDB RDS console. You can also use the ApsaraDB RDS API or execute SQL statements to create and manage standard accounts. You must grant the permissions on specific databases to each standard account. A standard account of an RDS instance does not have the permissions to create, manage, or disconnect the other accounts of the RDS instance. For more information, see Create an account. |
Limits on SQL statements
The limits on SQL statements in ApsaraDB RDS for PostgreSQL are the same as the limits on SQL statements in open source PostgreSQL. For more information, see SQL Commands and PostgreSQL Limits.
Other limits
Item | Description |
Public endpoint | If you want to connect to an RDS instance by using a public endpoint, you must manually apply for a public endpoint for the RDS instance. For more information, see View and change the endpoints and port numbers. |
Replication | ApsaraDB RDS for PostgreSQL supports primary/secondary replication in all RDS editions except for RDS Basic Edition. In primary/secondary replication, a secondary RDS instance is provided as a standby for the primary RDS instance. Secondary RDS instances are invisible to you and cannot be accessed by your applications. |
Instance restart | You can restart an RDS instance only in the ApsaraDB RDS console or by using the ApsaraDB RDS API. |
Tablespace creation | You cannot create tablespaces. |