This topic describes how to upgrade or downgrade the configurations of a PolarDB cluster. It takes only 5 to 10 minutes for the new configurations of each node to take effect. You can change the cluster configurations to meet your business requirements.


The cluster configurations are not being changed.

Background information

PolarDB supports online scaling. During the process of changing the cluster configurations, you do not need to lock the database.

You can change the cluster configurations to meet your business requirements. PolarDB allows you to use the following methods to improve capacity:

  • Vertical scaling of computing capabilities: Upgrade or downgrade the specifications of a cluster. This topic describes the details about this capacity scaling method.
  • Horizontal scaling of computing capabilities: Add or remove read-only nodes. For more information, see Add or remove read-only nodes.
  • Horizontal scaling of storage capacity: PolarDB uses a serverless architecture. The storage capacity is automatically increased or decreased based on the volume of your data. If you need to store large volumes of data, we recommend that you purchase PolarDB storage packages to reduce costs. For more information, see Use storage packages.

Configuration change fees

For more information, see Configuration change fees.


The automatic scale-out and automatic scale-in features are supported for only the PolarDB for MySQL clusters for which the value of Product Type is Pay-As-You-Go. These features are not supported for Subscription clusters. For more information about the product types of PolarDB clusters, see Create a PolarDB for MySQL cluster.


  • Configuration upgrades or downgrades apply to only clusters. You cannot change the configurations of a single node.
  • Configuration upgrades or downgrades do not affect the existing data in clusters.
  • We recommend that you change cluster configurations during service off-peak hours. During a configuration upgrade or downgrade, the PolarDB service is disconnected for a few seconds and some features are disabled. You must reconnect to PolarDB from your application after PolarDB is disconnected.
  • When the PolarDB cluster is running as expected, the latency of read-only requests is longer than that of read/write requests. When you change the configurations for your PolarDB cluster, the latency difference between read-only requests and read/write requests may become larger.

Manual configuration change

  1. Log on PolarDB console.
  2. On the top of the page, select the region where the target cluster is located.
  3. You can go to the Change Configurations dialog box by using the following methods:
    • Method 1
      On the Clusters page, find the cluster whose configurations you want to change, and click Change Configurations in the Actions column.Clusters
    • Method 2
      1. On the Clusters page, click the ID of the cluster whose configurations you want to change.
      2. In the Database Nodes section of the Overview page, click Scale.Scale
  4. In the dialog box that appears, select Upgrade or Downgrade based on your business requirements. Then, click OK.
    Change Configurations dialog box
  5. On the Upgrade/Downgrade page, select the node specifications. Then, read the service agreement, select the check box, and click Buy Now.
    Note All the nodes in a cluster have the same specifications.
  6. On the Purchase page, confirm the order information and click Purchase.
    Note It takes about 10 minutes for the new specifications to take effect.

Automatic configuration change

The diagnosis feature of PolarDB for MySQL integrates with some features of Database Autonomy Service (DAS). On the Autonomy Center tab, you can enable the automatic scale-out and automatic scale-out features. For more information, see Autonomy center.

Related API operations

API Description
ModifyDBNodeClass Changes the node specifications of a specified PolarDB cluster.