PolarDB:Perform a temporary cluster upgrade

Usage notes

• PolarDB clusters do not support temporary downgrades.

• When PolarDB temporarily scales up or back a cluster, transient connections to the cluster may occur. Make sure that your application is configured with the automatic reconnection mechanism.

• The rollback time must be at least one day before the expiration date of the cluster. For example, if a cluster expires on January 10, the restoration time must be on January 9 at latest.

• If a cluster is temporarily upgraded, you cannot add nodes to the cluster or remove nodes from the cluster. In addition, the cluster does not support automatic scaling. For more information about how to add or remove node, see Add or remove read-only nodes. If you want to perform manual horizontal scaling or use automatic scaling when the temporary upgrade is still effective, you must permanently upgrade the cluster. For more information, see Permanently retain the temporarily upgraded specifications.

• When the temporary upgrade remains effective (the cluster is in the running state), you can perform manual upgrades. For more information about how to manually upgrade a cluster, see Manually upgrade or downgrade a PolarDB cluster.

• The earliest scale-back time that you can specify is 1 hour after the cluster is upgraded. We recommend that you set the validity period of a temporary upgrade to no more than 14 days.

• After you perform a temporary upgrade, if the cluster still does not meet your business requirements or you want to extend validity period of the temporary upgrade, you can perform another temporary upgrade before the first temporary upgrade is rolled back. The rollback time of the second temporary upgrade must not be earlier than that of the first temporary upgrade.

Permanently retain the temporarily upgraded specifications

If you want to retain the specifications used for the temporary upgrade, you can perform a manual upgrade when the temporary upgrade is still effective (the cluster is in the running state). In this case, the cluster is not scaled back to the original specifications when the scale-back time is reached. To perform a manual upgrade, choose Upgrade in the Change Configurations dialog box. For more information, see Manually upgrade or downgrade a PolarDB cluster.

Select different specifications for the primary node and read-only nodes

For a PolarDB cluster, you can perform separate temporary upgrades for the primary node and read-only nodes. This means that you can select different specifications for the primary node and read-only nodes.

Limits

• Each cluster must contain at least one read-only node that has the same specifications as the primary node.

• Make sure that the specifications of the read-only nodes do not significantly differ from the specifications of the primary node:

  • Make sure that the memory of a read-only node is no less than half of the memory of the primary node.

  • Make sure that the numbers of CPU cores of the primary node and read-only nodes meet the mapping relationships described in the following table.

    CPU cores for primary node	Minimum CPU cores for read-only node
    2	2
    4	4
    8	4
    16	8
    32	16
    64	32
    88	32

• The specifications of the read-only nodes that serve as hot standby nodes must be the same as the specifications of the primary node. For more information about hot standby nodes, see Configure hot standby nodes.

• For read-only column store nodes, we recommend that you use specifications higher than the specifications of the primary node. For more information, see Add a read-only column store node.

Billing

A temporary upgrade fee is 1.5 times the price difference between the original and new specifications. For example, the validity period of a temporary upgrade is N days. You can calculate the temporary upgrade fee by using the following formula:

Temporary upgrade fee = (Monthly subscription fee for the new specifications - Monthly subscription fee for the original specifications)/30 × 1.5 × N

Procedure

1. Log on to the PolarDB console.

2. In the left-side navigation pane, click Clusters.

3. In the upper-left corner, select the region where the cluster to which you want to connect is deployed.

4. On the Clusters page, find the cluster on which you want to perform a temporary upgrade.

5. Open the Change Configurations (Subscription) dialog box by using one of the following two methods:

   • Find the cluster on which you want to perform a temporary upgrade, and click Change Configurations in the Actions column.

   • Find the cluster on which you want to perform a temporary upgrade and click the cluster ID to go to the Basic Information page. In the Database Nodes section, click Change Configurations.

6. In the Change Configurations (Subscription) dialog box, select Temporary Upgrade and click OK.

   Note

   Temporary Upgrade is available only for subscription clusters.

7. In the dialog box that appears, configure parameters described in the following table.

   Parameter	Description
   Resource Type	The new category of the cluster. Valid values: General Specification and Dedicated Specification.
   Node	The new node specifications that you want to use. Note Make sure that at least one read-only node has the same specifications as the primary node.
   Restore Time	The time when the temporary upgrade expires. When the time is reached, the cluster is restored to the original specifications. Note After you perform a temporary upgrade, if the cluster still does not meet your business requirements or you want to extend the validity period of the temporary upgrade, you can perform another temporary upgrade before the first temporary upgrade is rolled back. The scale-back time of the second temporary upgrade must not be earlier than that of the first temporary upgrade. The minimum validity period for a temporary upgrade is one hour. We recommend that you set the validity period to up to 14 days. It is because the restoration time cannot be changed after it is specified. The rollback time must be at least one day before the expiration date of the cluster.

8. Read and select the terms of service, click Buy Now, and then complete the payment.

9. On the Purchase page, confirm the order information and click Subscribe.