A PolarDB cluster consists of three layers: the database proxy (PolarProxy), the database kernel (DB), and the distributed storage (Store). Upgrading the minor version delivers the latest features and bug fixes. PolarProxy and the kernel can be upgraded independently or together.
Upgrade impact by type
Each upgrade type affects different endpoints and has a different downtime profile.
|
Upgrade type |
Affected endpoints |
Estimated downtime |
Connection Preserving |
|
Upgrade PolarDB Database Proxy and Kernel |
All endpoints |
30-90 seconds |
Not available |
|
Upgrade PolarDB Database Proxy Only |
Cluster endpoint, custom endpoints |
30 seconds |
Not available |
|
Upgrade Kernel Only |
Primary endpoint, cluster endpoint |
30-60 seconds |
Available (PolarProxy 2.3.50 or later) |
When you select Upgrade PolarDB Database Proxy and Kernel, the only impact is the 30-90 second disconnection. Normal cluster operations are not affected.
A proxy-only upgrade covers features related to read/write splitting — including consistency level (global consistency), transaction splitting, and whether the primary database accepts read requests. The primary endpoint is not affected.
Connection Preserving
When you upgrade the kernel only, PolarDB clusters running PolarProxy 2.3.50 or later can use the Connection Preserving feature to keep 95% of database connections from being interrupted.
Before you begin
An upgrade typically takes no more than 30 minutes. During the upgrade, PolarProxy or the database kernel restarts, causing transient disconnections. Schedule the upgrade during off-peak hours and make sure your application has an automatic reconnection mechanism.
During the upgrade, operations that change the cluster state are unavailable — including configuration changes (upgrade/downgrade), adding or deleting nodes, modifying parameters, and restarting nodes. Query features such as performance monitoring are not affected.
Downgrades are not supported. The version cannot be rolled back after an upgrade.
If you configured CloudMonitor alerts for your PolarDB cluster, expect alert notifications about cluster access exceptions during the upgrade.
View version information
Log on to the PolarDB console. In the left-side navigation pane, click Clusters. Select the region where the cluster is located, and then click the cluster ID to go to the cluster details page.
In the left-side navigation pane, choose Settings and Management > Version Management.
On the Minor Version Upgrade page, view the current proxy and kernel versions in the Version Information section.
Upgrade the version
If the current proxy or kernel version is not the latest, upgrade it from the same page.
Prerequisites
Before you begin, ensure that you have:
Reviewed the upgrade impact table and selected the appropriate upgrade type
An automatic reconnection mechanism in your application
A maintenance window scheduled during off-peak hours
Procedure
The upgrade causes transient disconnections on the affected endpoints. Review the upgrade impact table before proceeding and make sure your application has a reconnection mechanism in place.
-
Go to Settings and Management > Version Management for the target cluster. On the Minor Version Upgrade page, in the Upgrade Version section, select one of the following options:
Upgrade PolarDB Database Proxy and Kernel
Upgrade Kernel Only
Upgrade PolarDB Database Proxy Only
If the current proxy or kernel version is already the latest, these options are grayed out.
Click Upgrade Now or Upgrade in Maintenance Window. If you select Upgrade in Maintenance Window, view task details or cancel the task on the Scheduled Tasks page. For more information, see Scheduled tasks.