After you enable the read/write splitting feature for an ApsaraDB RDS for SQL Server instance, you can modify the read weight of the RDS instance based on your business requirements.

Prerequisites

  • Your RDS instance is a primary RDS instance and meets the following requirements:
    • The RDS instance runs SQL Server 2017 on RDS Cluster Edition or SQL Server 2019 on RDS Cluster Edition.
    • The RDS instance runs RDS Cluster Edition.
    • The RDS instance uses the enhanced SSD (ESSD) storage type.
    Note You can go to the Basic Information page of the RDS instance to view the preceding information.
  • The read/write splitting endpoint is enabled for the RDS instance. For more information, see Enable the read/write splitting endpoint for an ApsaraDB RDS for SQL Server instance.

Procedure

  1. Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.
  2. In the left-side navigation pane, click Cluster Management.
  3. Click Configure Readonly Splitting Address . In the dialog box that appears, select Customized Distribution and configure read weights.

    A higher read weight indicates more read requests to process. For example, if the primary RDS instance has three read-only RDS instances whose read weights are 100, 200, and 200, the read-only RDS instances process read requests at a ratio of 1:2:2.

    • Automatic Distribution: The system automatically assigns a read weight to each RDS instance in your database system based on the specifications of the RDS instance. After you create a read-only RDS instance, the system automatically assigns a read weight to the read-only RDS instance and adds the read-only RDS instance to the read/write splitting link. No manual intervention is required. For more information, see Default read weights.
    • Customized Distribution: You must manually specify a read weight for each RDS instance in your database system based on your business requirements. Valid values: 0 to 10000. By default, the read weight of a read-only RDS instance is 0. After you create a read-only RDS instance, you must manually specify a read weight for the read-only RDS instance based on your business requirements.
    Note If you delete a read-only RDS instance, its read weight is also removed, but the read weights of other RDS instances remain unchanged.
  4. Click OK.