This topic describes how to change the specifications of an ApsaraDB RDS for PostgreSQL instance. The specifications include the RDS edition, instance type, and storage capacity.

Prerequisites

Your Alibaba Cloud account does not have unpaid renewal orders.

Configuration items

You can create read-only RDS instances to increase the read capability of your database system. The read-only RDS instances can offload queries from the primary RDS instance. For more information, see Overview of read-only ApsaraDB RDS for PostgreSQL instances and Create a read-only ApsaraDB RDS for PostgreSQL instance.

Notice When you change some specifications of your RDS instance, ApsaraDB RDS may migrate the data of your RDS instance to a new RDS instance. After the migration is complete, ApsaraDB RDS switches your workloads over to the new RDS instance. During the switchover, a transient connection or instance restart may occur. You cannot perform most of the operations that are related to databases, accounts, and network settings during the switchover. We recommend that you change the specifications of your RDS instance within the specified maintenance window. For more information, see Set the maintenance window of an ApsaraDB RDS for PostgreSQL instance.
Configuration item Background information Impact
RDS edition You can upgrade an RDS instance from RDS Basic Edition to RDS High-availability Edition. For more information, see Upgrade an ApsaraDB RDS for PostgreSQL instance from Basic Edition to High-availability Edition. A transient connection that lasts a few seconds occurs.
Storage types
  • Basic Edition: If your RDS instance runs RDS Basic Edition with enhanced SSDs (ESSDs), you can upgrade or downgrade the ESSD storage type of your RDS instance between ESSD PL1, ESSD PL2, and ESSD PL3.
  • High-availability Edition:
    • If your RDS instance runs RDS High-availability Edition with SSDs or ESSDs, take note of the following items:
      • You can upgrade the storage type of your RDS instance from SSDs to ESSDs. ESSDs support the following performance levels (PLs): ESSD PL1, ESSD PLs, and ESSD PL3. You cannot downgrade the storage type of your RDS instance from ESSDs to SSDs.
      • You can upgrade or downgrade the ESSD storage type of your RDS instance between ESSD PL1, ESSD PL2, and ESSD PL3.
    • If your RDS instance runs RDS High-availability Edition with local SSDs, you cannot change the storage type of your RDS instance.
Note For more information about the performance differences between different storage types, see Storage types.
  • If you upgrade or downgrade the ESSD storage type of your RDS instance between ESSDs PL1, ESSDs PL2, and ESSDs PL3, no transient connections occur.
  • If you upgrade the storage type of your RDS instance from SSDs to ESSDs, a transient connection that lasts a few seconds occurs.
Instance type You can change the instance type of your RDS instance regardless of the instance configuration.
Note
An RDS instance can be changed from a new general-purpose instance type to another instance type that can provide more than 16 cores. For more information, see Primary ApsaraDB RDS for PostgreSQL instance types.
  • The instance type of an RDS instance that runs RDS Basic Edition can be changed from a new general-purpose instance type to a general-purpose instance type.
  • The instance type of an RDS instance that runs RDS High-availability Edition can be changed from a new general-purpose instance type to a dedicated instance type.
  • If you upgrade the instance type of your RDS instance, a transient connection that lasts a few seconds occurs.
  • If you downgrade the instance type of your RDS instance, the primary RDS instance is restarted. After the primary RDS instance is restarted, a transient connection that lasts a few seconds occurs.
Storage capacity You can increase the storage capacity of your RDS instance regardless of the instance configuration.
Note
  • The new storage capacity that you specify for your RDS instance must be within the storage capacity range that is supported by the instance type of the instance. For more information, see Primary ApsaraDB RDS instance types.
  • You cannot decrease the storage capacity of your RDS instance by changing the specifications of the instance. You can use the cloud migration feature to decrease the storage capacity. For more information, see Scale down an ApsaraDB RDS for PostgreSQL instance.
  • If the storage capacity range that is supported by the instance type of your RDS instance does not meet your business requirements, we recommend that you change the instance type of your RDS instance.
  • You can manually change the storage capacity of your RDS instance that uses standard SSDs or ESSDs. Alternatively, you can configure automatic storage expansion. After you configure automatic storage expansion and when the percentage of the remaining storage reaches a specified threshold, your RDS instance automatically scales up the storage capacity to ensure stable service operations. For more information, see Configure automatic storage expansion for an ApsaraDB RDS for PostgreSQL instance.
  • If your RDS instance uses standard SSDs or ESSDs, no transient connections occur when you increase the storage capacity of your RDS instance.
  • If your RDS instance uses local SSDs, a transient connection that lasts a few seconds occurs when you increase the storage capacity of your RDS instance.

Billing

For more information, see Specification change fees.

Precautions

  • If your RDS instance runs RDS Basic Edition, no secondary RDS instance is provided as a hot standby. In this case, if your RDS instance unexpectedly exits, your database service may be unavailable for a long period of time. If you change the specifications or upgrade the database engine version of your RDS instance, your database service may also be unavailable for a long period of time. If you have high requirements for service availability, we recommend that you do not use RDS Basic Edition.
    Note Whether a transient connection occurs during the specification changes varies based on the different configuration items. For more information, see the Impact column of the Configuration items.
  • When you change some specifications of your RDS instance, ApsaraDB RDS may migrate the data of your RDS instance to a new RDS instance. After the migration is complete, ApsaraDB RDS switches your workloads over to the new RDS instance. During the switchover, a transient connection or instance restart may occur. You cannot perform most of the operations that are related to databases, accounts, and network settings during the switchover. We recommend that you change the specifications of your RDS instance within the specified maintenance window. For more information, see Set the maintenance window of an ApsaraDB RDS for PostgreSQL instance. For more information about the impacts of different configuration items, see the Impact column.
  • After you change the specifications of your RDS instance, the ID and endpoints of the instance remain unchanged.
  • After you change the specifications of your RDS instance, you do not need to manually restart the instance.

Procedure

  1. Access RDS Instances, select a region at the top, and then click the ID of the target RDS instance.
  2. In the Configuration Information section of the Basic Information page, click Change Specifications.
  3. In the dialog box that appears, select a specification change method and click Next step. This step is required only when the RDS instance uses the subscription billing method.
    Note Upgrade or Downgrade:
    • After you submit a specification change order, ApsaraDB RDS synchronizes the data of the RDS instance from the disk to a new RDS instance. Then, ApsaraDB RDS switches the information, such as the instance ID and endpoints, about the RDS instance over to the new RDS instance based on the specified switching time.
    • If you select Downgrade, the primary RDS instance is restarted during the switchover. We recommend that you change the specifications of the RDS instance within the specified maintenance window. For more information, see Set the maintenance window of an ApsaraDB RDS for PostgreSQL instance
  4. Change the specifications of the RDS instance. For more information about the supported configuration items, see Configuration items.
  5. Configure the Switching Time parameter.
    • Switch Immediately After Data Migration: The specification change triggers a data migration to a new RDS instance. If you select this option, ApsaraDB RDS immediately applies the specification change and switches your workloads over to the new RDS instance after the migration process is complete.
    • Switch Within Maintenance Window: When the specification change is being applied, a transient connection or instance restart may occur and you cannot perform most of the operations that are related to databases, accounts, and network settings. If you select this option, ApsaraDB RDS applies the specification change during the maintenance window that you specify. For more information, see Set the maintenance window of an ApsaraDB RDS for PostgreSQL instance.
    Note If you only increase the storage capacity of the RDS instance or only change the ESSD storage type of the RDS instance between ESSDs PL1, ESSDs PL2, and ESSDs PL3, your business is not affected. ApsaraDB RDS immediately applies the specification change. In this case, you do not need to select Switch Within Maintenance Window.
  6. Read and select Terms of Service, click Pay Now, and then complete the payment.
    Warning
    • After you submit a specification change order, you cannot cancel the order. Therefore, before you submit a specification change order, we recommend that you evaluate whether the new specifications meet your business requirements.
    • After you submit a specification change order, do not perform DDL operations before the specification change is applied.

FAQ

  1. How do I change the storage type of my RDS instance from standard SSDs or ESSDs to local SSDs?

    For more information, see How do I migrate an ApsaraDB RDS instance from standard or enhanced SSDs to local SSDs?.

  2. If I increase only the storage capacity of my RDS instance, does ApsaraDB RDS migrate the data of my original RDS instance to a new RDS instance?

    This depends on whether the host on which your RDS instance resides has sufficient storage. If the host has sufficient storage, no data migration is required. Otherwise, ApsaraDB RDS migrates the data to a host that has sufficient storage.

  3. How do I decrease the storage space of my RDS instance?
    You cannot decrease the storage capacity of your RDS instance by changing the specifications of the instance.

Related operations

Operation Description
ModifyDBInstanceSpec Changes the specifications of an ApsaraDB RDS instance.