PolarDB：Temporary 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 can automatically reconnect to the cluster.
• The scale-back time must be at least one day before the expiration date of the cluster. For example, if a cluster expires on January 10, the scale-back time cannot be later than January 9.
• 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 nodes, see Add or remove a read-only node. 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 the "Permanently retain the temporarily upgraded specifications" section of this topic.
• 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 Change the specifications of a PolarDB cluster.
• The minimum validity period for a temporary upgrade is 1 hour. 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 the validity period of the temporary upgrade, you can perform another temporary upgrade before the first temporary upgrade becomes ineffective. The scale-back time of the second temporary upgrade must not be earlier than that of the first temporary upgrade.

Permanently retain the temporarily upgraded specifications

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

For a PolarDB for MySQL 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

• In a cluster, at least one read-only node must have the same specifications as the primary node.
• We recommend that you select similar specifications for the primary node and read-only nodes:
  • The memory of a read-only node cannot be less than half of the memory of the primary node.
  • The following table lists the correspondence of CPU specifications for the primary node and read-only nodes.

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

Billing

The fee of a temporary upgrade is 1.5 times the price difference between the original and new specifications. For example, assume that 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 upper-left corner of the console, select the region in which the cluster that you want to manage is deployed.
3. On the Clusters page, find the cluster for which you want to perform a temporary upgrade.
4. Open the Change Configurations (Subscription) dialog box by using one of the following two methods:
   • Find the cluster that you want to upgrade and click Change Configurations in the Actions column.
   • 1. Find the cluster that you want to upgrade and click the cluster ID to navigate to the Basic Information page.
     2. In the Database Nodes section, click Change Configurations.
5. On the Change Configurations (Subscription) page, select Temporary Upgrade and click OK.
   Note Temporary Upgrade is available only for subscription clusters.
6. On the page that appears, specify the following parameters.

   Parameter	Description
   Specification Type	The specification type of the upgraded cluster. By default, this parameter is set to Dedicated.
   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.
   PolarProxy Type	The PolarProxy type of the upgraded cluster. By default, this parameter is set to Dedicated Enterprise.
   Restore Time	The time when the temporary upgrade expires. When the time is reached, the cluster is scaled back 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 becomes ineffective. 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 1 hour. We recommend that you set the validity period of a temporary upgrade to no more than 14 days. It is because the scale-back time cannot be changed after it is specified. The scale-back time must be at least one day before the expiration date of the cluster.

7. Read and accept the terms of service and then click Buy Now.
8. On the Purchase page, confirm the order information and click Purchase.