The architecture of a PolarDB cluster consists of three layers: PolarProxy, the database engine, and the distributed storage. You can upgrade PolarProxy or the database engine separately or upgrade both of them at the same time.

Usage notes

  • In most cases, an upgrade requires less than 30 minutes to complete. PolarProxy or the database engine is restarted during the upgrade. This can cause transient connections to occur on the database. We recommend that you perform the upgrade during off-peak hours. Make sure that your application can automatically reconnect to your database.
  • During the Upgrade PolarDB Database Proxy and Kernel process, transient connections occur for the primary endpoint and the cluster endpoint and last for 30 to 90 seconds. Make sure that your application can automatically reconnect to your database.
  • During the Upgrade PolarDB Database Proxy Only process, transient connections occur for the cluster endpoint and the custom endpoint and last for 30 seconds. Make sure that your application can automatically reconnect to your database.
  • During the Upgrade Kernel Only process, PolarDB clusters with PolarProxy of V2.4.7 or later can use the connection preservation technique to prevent 95% of the database connections from being interrupted.
  • During the upgrade, you cannot use some features that are related to cluster changes in the PolarDB console. For example, you cannot upgrade or downgrade configurations, add or delete nodes, modify parameters, or restart nodes. During this period, features related to data queries are still available, such as performance monitoring.
  • You cannot downgrade PolarProxy or the database engine.

View the version information

  1. Log on to the PolarDB console.
  2. In the upper-left corner of the console, select the region where the cluster that you want to manage is deployed.
  3. Find the cluster you want to manage and click the cluster ID.
  4. In the Version Information section, view the version information of PolarProxy and the database engine.

Upgrade the version

If PolarProxy or the database engine of the cluster is not of the latest version, you can upgrade the version based on your business requirements.

  1. On the details page of the cluster that you want to manage, choose Settings and Management > Version Management. In the Upgrade Version section, select Upgrade PolarDB Database Proxy and Kernel, Upgrade Kernel Only, or Upgrade PolarDB Database Proxy Only as needed.
    Upgrade the minor version of the database engine
    Note
    • If PolarProxy or the database engine of the cluster is of the latest version, the Upgrade PolarDB Database Proxy and Kernel, Upgrade Kernel Only, and Upgrade PolarDB Database Proxy Only options are unavailable.
    • If you select Upgrade PolarDB Database Proxy Only, only the features related to read/write splitting are upgraded, such as the consistency level, transaction splitting, and whether to offload reads from the primary node. The default consistency level is global consistency.
  2. Click Upgrade Now or Upgrade in Maintenance Window.

    If you select Upgrade in Maintenance Window, you can view the details of the task or cancel the task on the Scheduled Tasks page. For more information, see View or cancel a scheduled task.

    Notice
    • During the Upgrade PolarDB Database Proxy and Kernel process, transient connections occur for the primary endpoint and the cluster endpoint and last for 30 to 90 seconds. Make sure that your application can automatically reconnect to your database.
    • During the Upgrade PolarDB Database Proxy Only process, transient connections occur for the cluster endpoint and the custom endpoint and last for 30 seconds. Make sure that your application can automatically reconnect to your database.
  3. In the dialog box that appears, click OK.

Related API operations

API Description
DescribeDBClusterVersion Queries the details about the database engine version of a PolarDB for MySQL cluster.
UpgradeDBClusterVersion Upgrades a PolarDB for MySQL cluster to the latest version.