Modify the read weight of an SQL Server read-only endpoint - ApsaraDB RDS

When read traffic is unevenly distributed across your read-only instances—such as when analytics or reporting queries compete with transactional workloads—you can assign custom weights to each instance at the read-only routing endpoint. The read-only routing endpoint automatically forwards read requests to secondary nodes or all involved read-only instances based on the configured weights. This lets you direct heavier workloads to higher-capacity instances, isolating them from write traffic and improving overall read/write splitting performance.

Prerequisites

Before you begin, make sure you have:

A read-only instance attached to your ApsaraDB RDS for SQL Server instance. See Create a read-only ApsaraDB RDS for SQL Server instance

Modify read weights

Log on to the ApsaraDB RDS console. On the Instances page, select the region where your instance resides, then click the instance ID.
In the left-side navigation pane, click Cluster Management.

In the Basic Information section, click Configure Readonly Splitting Address. In the dialog box that appears, set Read Weight to Customized Distribution and configure Distribution. Choose the distribution mode that fits your setup:

Note

A higher weight means the instance handles more read requests. For example, three read-only instances with weights 100, 200, and 200 process read traffic at a 1:2:2 ratio. If you delete a read-only instance, its weight is removed, but the weights of all other instances remain unchanged.

Mode	Behavior
Automatic Distribution	The system assigns weights based on instance specifications. Weights for new read-only instances are assigned automatically—no manual input required. See Rules of weight allocation by the system
Customized Distribution	Specify a weight for each instance. Valid values: 0–10,000. New read-only instances default to 0 and must be set manually

Click OK.

What's next

If your RDS instance uses RDS Cluster Edition, secondary nodes are readable by default and can also receive read traffic. See Configure the read attribute for a secondary RDS instance.
To stop routing read traffic through the read-only routing endpoint entirely, see Disable read/write splitting by disabling the read-only routing endpoint.