PolarDB:Enable the serverless feature for a cluster with defined specifications

Version requirements

To enable the serverless feature for a cluster with defined specifications, the cluster must meet the following version requirements:

• Edition: Enterprise Edition.

• Series: Dedicated.

• Database engine: PostgreSQL 14 with a minor engine version of 14.13.27.0 or later.

Usage notes

When you enable the serverless feature for a cluster with defined specifications, the cluster experiences a transient connection that lasts about 15 to 30 seconds. If the current host has insufficient resources, the cluster may be migrated to an idle host. Therefore, we recommend that you enable the serverless feature during off-peak hours.

Display format

PolarProxy PolarProxy includes resources with defined specifications and serverless resources. The serverless resources are scaled based on the workloads. The serverless resources are scaled in units of 0.5 PCUs. The number of PCUs added or removed in a scaling activity is positively correlated with the number of PCUs used. Compute nodes The primary node and read-only nodes include the resources with defined specifications and the serverless resources. The resources with defined specifications cannot be scaled, whereas the serverless resources can be scaled based on the workloads. The number of PCUs increases or decreases based on the scaling of the primary node or read-only nodes. Resources are scaled in units of 0.5 PCUs. The number of PCUs added or removed in a scaling activity is positively correlated with the number of PCUs used. You can set the scaling range of a node in PCUs. The system monitors the PCUs of a compute node every second. Storage The storage of the common cluster with defined specifications is used. For more information, see Storage. Note After you enable the serverless feature for an existing cluster with defined specifications, the maximum number of connections to the cluster and the maximum IOPS of the cluster are proportional to the specified value of the Maximum Resources for Single Node parameter.

Billing

The fees for the serverless feature of a cluster with defined specifications consist of two parts: fees for the cluster with defined specifications and fees for the serverless feature. For information about the fees for clusters with defined specifications, see Billing of clusters with defined specifications. For information about the fees for the serverless feature, see Serverless billing.

Procedure

1. Log on to the PolarDB console. In the navigation pane on the left, click Clusters. Select the region where the cluster is deployed, and then click the cluster ID to open the cluster details page.

2. On the Basic Information page, in the Database Nodes section, click Enable Serverless.

   

3. In the Enable Serverless dialog box, set the following parameters and click OK.

   • Maximum Resources for Single Node: As shown in Architecture, this parameter specifies the upper limit of serverless resources for the original nodes in the cluster with defined specifications. This is the upper limit for vertical scaling. Valid values: 0 to 16 PCU.

   • Minimum Resources for Single Node: As shown in Architecture, this parameter specifies the lower limit of serverless resources for the original nodes in the cluster with defined specifications. This is the lower limit for vertical scaling. Valid values: 0 to 16 PCU. The minimum value must be less than or equal to the maximum value.

   Note

   • This value does not include the original resources of the cluster with defined specifications. After you set this parameter, the vertical scaling range for the original nodes in the cluster is (Defined specifications + Lower limit) to (Defined specifications + Upper limit).

   • The vertical scaling range for auto-scaled serverless read-only nodes is 1 to 32 PCU by default. You do not need to configure this.

   • Example: Assume that you set Minimum Resources for Single Node to 2 PCU and Maximum Resources for Single Node to 8 PCU. The resource specification of the original nodes in the cluster starts at Defined specifications + 2 PCU (approximately 2 cores and 4 GB of memory). When the system detects an increase in workload, it automatically increases the number of PCUs for the nodes. However, based on the settings, the number of added PCUs can be increased to a maximum of 8 PCU (approximately 8 cores and 16 GB of memory). This means the total resource specification of the original nodes can be increased to a maximum of Defined specifications + 8 PCU (approximately 8 cores and 16 GB of memory).

   • Maximum Number of Read-only Nodes: The maximum number of serverless read-only nodes that can be added to the cluster. Valid values: 0 to 15.

   • Minimum Number of Read-only Nodes: The minimum number of serverless read-only nodes that can be added to the cluster. Valid values: 0 to 15. This value cannot be greater than the maximum value.

   Note

   • This value does not include the number of original read-only nodes in the cluster.

   • A cluster can have a maximum of 15 read-only nodes. Therefore, the total number of original read-only nodes and auto-scaled read-only nodes cannot exceed 15.

   • Example: Assume that you set Minimum Number of Read-only Nodes to 1 and Maximum Number of Read-only Nodes to 2. The cluster maintains one auto-scaled read-only node in addition to the original number of read-only nodes. When the system detects an increase in workload, it automatically adds more read-only nodes. Based on the settings, a maximum of two auto-scaled read-only nodes can be added.

References

Manage the serverless feature for a cluster with defined specifications

Related API operations