How to temporarily upgrade the specifications of a PolarDB node - PolarDB

When your business anticipates predictable, short-term traffic surges, such as during e-commerce promotions or online events, your database may face performance bottlenecks due to insufficient compute resources. A permanent upgrade can lead to resource waste after the traffic subsides. The PolarDB temporary upgrade feature allows you to increase the compute specifications (CPU and memory) of a subscription cluster for a specified period. The cluster automatically reverts to its original specifications at a scheduled time, helping you handle short-term peak workloads cost-effectively.

Impact assessment

Before you perform a temporary upgrade, assess the potential impact on your services to create a change plan.

Service impact

Changing the specifications of a PolarDB cluster triggers a node restart, which can cause transient connection interruptions and brief performance fluctuations. The impact depends on whether your cluster supports the seamless switchover feature and whether binary logging (binlog) is enabled.

If your cluster does not support seamless switchover, a transient connection interruption of about 20 to 30 seconds may occur during the specification change. Before the switchover, ensure your application has a connection retry mechanism.
If your cluster supports seamless switchover, the impact varies with the binlog status. If binlog is enabled, a transient connection interruption of about 5 to 10 seconds may occur. If binlog is disabled, performance may drop to zero for 1 to 3 seconds, but connections and transactions will not be interrupted.

Important

Task duration: The change task takes about 5 minutes per node. For example, changing two nodes takes about 10 minutes. The exact duration is affected by factors such as cluster load and the number of databases and tables.
Replication lag: During the change, the data replication lag on read-only nodes may be longer than during normal operation.
Data safety: The configuration change only adjusts node resources and does not affect any existing data in the cluster.
Restart order: When you change the specifications of both the primary and read-only nodes at the same time, the system restarts the read-only nodes first, followed by the primary node. No primary/standby switchover occurs during this process.

Node specification limits

To ensure cluster stability and high availability, the following limits apply when you configure the specifications for the primary and read-only nodes:

At least one read-only node must have the same specifications as the primary node.
Read-only nodes with hot standby enabled must have the same specifications as the primary node.
The memory of a read-only node cannot be less than half the memory of the primary node.

The number of CPU cores for a read-only node must meet the minimum requirements listed in the following table:

Primary node CPU	Minimum read-only CPU
2	2
4	4
8	4
16	8
32	16
64	32
88	64
120	64

Note

The Multi-master Cluster (Limitless) Edition is not subject to the preceding limits.

Other limitations

During a temporary upgrade, you can perform at most one additional upgrade.
During a temporary upgrade, you cannot perform operations such as a manual configuration change, adding or removing nodes, temporarily adding nodes, automatic scaling, or canceling the cluster subscription.

Prerequisites

Before you begin, complete the following checks.

Billing method: The target cluster must be a Subscription cluster.
Cluster status: The target cluster must be in the Running state, with no other configuration tasks in progress, such as adding or removing a node, or a minor version upgrade.
Pending tasks: No other configuration change tasks, such as adding or removing a node or changing configurations, are pending.
Service-linked role authorization: You must have created the PolarDB service-linked role AliyunServiceRoleForPolarDB for your account.
Click to expand to see how to check if the PolarDB service-linked role has been created
1. Navigate to the Identity > Roles page in the RAM console.
2. Search for AliyunServiceRoleForPolarDB in the role list to confirm that the service-linked role exists.
  1. If it exists, skip this check.
  2. If it does not exist, continue with the following steps.
3. Click Create Role. On the Create Role page, click Create Service-linked Role in the upper-right corner.
4. On the Create Service-linked Role page, select PolarDB from the Select Service drop-down list, and then click Create Service-linked Role to complete the creation.

Procedure

Log on to the PolarDB console. In the left-side navigation pane, click Clusters and select the region where your cluster is located.
Use one of the following methods to navigate to the Change Configurations (Subscription) page:
- Find the target cluster and click Change Configurations in the Actions column.
- Click the cluster ID to navigate to the Basic Information page. In the Database Nodes section, click Change Configurations. This page displays the specifications and status of the primary and read-only nodes and provides links to Add or Remove Nodes and Change Configurations.
In the Change Configurations (Subscription) dialog box, select Temporary Upgrade and click OK.

On the Temporary Upgrade page, confirm the Current Configuration and Expiration Time, and then set the following parameters:

Parameter	Description
Database Type	Select the target specification edition. Options include General Specification and Dedicated Specification.
Node	Select the target specifications for the node (primary or read-only) that you want to upgrade. Note You must ensure that at least one read-only node has the same specifications as the primary node. You can configure the specifications for other nodes as needed.
Restore Point	Set a specific time for the system to automatically restore the cluster to its pre-upgrade specifications. Note The minimum duration is 1 hour, and the maximum is 14 days. For upgrades longer than 14 days, we recommend using a manual configuration change. The restore time must be at least one day before the cluster's expiration date. For example, if the cluster expires on January 10, the latest restore time for a temporary upgrade is January 9. The restore time cannot be changed after it is set. If performance is insufficient and you need to extend the duration, you can perform one more upgrade before the restore time is reached. The new Restore Point cannot be earlier than the original one.

Read the terms of service, click Buy Now, and complete the payment. After the payment is successful, the upgrade task begins.

Billing

The fee for a temporary upgrade is based on the price difference between the new and original specifications, multiplied by a premium factor of 1.5. The formula is as follows:

Fee for temporarily upgrading a node for N days = (Monthly price of new specifications - Monthly price of original specifications) / 30 × 1.5 × N.

Related operations

Convert to a permanent upgrade

If you need to keep the upgraded specifications permanently or perform operations such as adding or removing nodes, temporarily adding nodes, automatic scaling, or canceling the cluster subscription, you can convert the temporary upgrade to a permanent one. After the conversion, the cluster will not automatically downgrade at the restore time.

Manual conversion: During the temporary upgrade period, navigate to the Change Configurations (Subscription) page again and perform a manual configuration change to the current specifications.

Note
This action only generates a permanent billing order and does not cause a second service interruption.
Conversion by scaling up storage space: If you manually scale up the cluster's storage space during the temporary upgrade period, the system automatically converts the temporary compute specifications to permanent specifications. This means you will be billed at the new subscription rate from the moment of storage expansion. Carefully evaluate this change before you scale up the storage.

View upgrade expiration time

Navigate to the Billing Management > Order > My Orders page, search by cluster ID, find the order with the order type Temporary Upgrade, and click View Details to view its information.

API reference

API	Description
TempModifyDBNode	Temporarily upgrades the specifications of a PolarDB cluster.

FAQ

What should I do if an "insufficient resources" error occurs during a temporary upgrade?

If you select specific node specifications during the upgrade process and receive a message like "Insufficient resources. Please try again after changing the region or availability zone", it means the selected specifications are sold out in the current availability zone. Try the following solutions:

Select similar specifications: Try selecting other, slightly lower specifications.
Change the availability zone: You can manually change the availability zone to prevent resource insufficiency issues in future configuration changes.

What should I do if the error The operation is not permitted due to loss polardb service linked role. occurs during a temporary upgrade?

This error indicates that your account has not been authorized with the PolarDB service-linked role AliyunServiceRoleForPolarDB. To resolve this, complete the steps in the Service-linked role authorization section.

What should I do if I see the error "The temporary upgrade expiration time cannot be earlier than: XXX"?

After a temporary upgrade, if performance is still insufficient and you need to extend the duration, you can perform one additional upgrade before the original restore time is reached. The new Restore Point must be at least one hour later than the restore time of the first upgrade.

How can I downgrade, add, or remove nodes for a cluster that has been temporarily upgraded?

During a temporary upgrade, operations like downgrading or adding and removing nodes are not supported. You must first convert the temporary upgrade to a permanent upgrade before you can perform these operations.