The architecture of a PolarDB cluster consists of the following layers: PolarProxy, the database engine, and the distributed storage system. You can individually update PolarProxy or the database engine or perform a concurrent update.
Usage notes
In most cases, an update requires less than 30 minutes to complete. PolarProxy or the database engine is restarted during the update. This may temporarily disrupt connections to the database. We recommend that you perform an update during off-peak hours. Make sure that your application can automatically reconnect to the database.
If you select the Upgrade PolarDB Database Proxy and Kernel option, connections to the database by using the primary endpoint or the cluster endpoint are interrupted for 30 to 90 seconds during the update. Make sure that your application can automatically reconnect to the database.
NoteDuring a revision version upgrade, the cluster is available except in the preceding period.
If you select the Upgrade PolarDB Database Proxy Only option, connections to the database by using the cluster endpoint or a custom endpoint are interrupted for 30 seconds during the update. Make sure that your application can automatically reconnect to the database.
If you select the Upgrade Kernel Only option, PolarDB clusters whose PolarProxy version is 2.4.7 or later can use the connection preservation technique to prevent 95% of the database connections from being interrupted.
During the update, you cannot use several features that are related to cluster changes in the PolarDB console. For example, you cannot upgrade or downgrade configurations, add or remove nodes, modify parameters, or restart nodes. During this period, features related to data queries, such as performance monitoring, are still available.
You cannot downgrade PolarProxy or the database engine.
View the version information
Log on to the PolarDB console. In the left-side navigation pane, click Clusters. In the upper-left corner, select the region of the cluster. In the cluster list, find the cluster and click its ID to go to its Basic Information page.
In the left-side navigation pane, choose .
On the Minor Version Upgrade tab, you can view the version information of PolarProxy and the database engine in the Version Information section.
Update the versions
If the version of PolarProxy or the database engine of the cluster is not the latest version, you can update the version based on your business requirements.
In the left-side navigation pane of the cluster page, choose . On the Minor Version Upgrade tab, select Upgrade PolarDB Database Proxy and Kernel, Upgrade Kernel Only, or Upgrade PolarDB Database Proxy Only in the Upgrade Version section based on your business requirements.
NoteIf the version of PolarProxy or the database engine of the cluster is the latest version, the Upgrade PolarDB Database Proxy and Kernel, Upgrade Kernel Only, and Upgrade PolarDB Database Proxy Only options are dimmed.
If you select the Upgrade PolarDB Database Proxy Only option, only the features related to read/write splitting are updated, such as the consistency level, transaction splitting, and the feature for offloading reads from the primary node. The default consistency level is global consistency.
Click Upgrade Now or Upgrade in Maintenance Window.
If you select the Upgrade in Maintenance Window option, you can view the details of the task or cancel the task on the Scheduled Tasks page. For more information, see Scheduled tasks.
ImportantIf you select the Upgrade PolarDB Database Proxy and Kernel option, connections to the database by using the primary endpoint or the cluster endpoint are interrupted for 30 to 90 seconds during the update. Make sure that your application can automatically reconnect to the database.
NoteDuring a revision version upgrade, the cluster is available except in the preceding period.
If you select the Upgrade PolarDB Database Proxy Only option, connections to the database by using the cluster endpoint or a custom endpoint are interrupted for 30 seconds during the update. Make sure that your application can automatically reconnect to the database.
If you select the Upgrade Kernel Only option, PolarDB clusters whose PolarProxy version is 2.4.7 or later can use the connection preservation technique to prevent 95% of the database connections from being interrupted.
Related API operations
Operation | Description |
Queries the database engine version information of a cluster. | |
Upgrades the database engine version of a cluster. |