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ApsaraDB RDS:CalculateDBInstanceWeight

Last Updated:May 22, 2024

Queries system-assigned read weights.

Operation description

Supported database engines

  • MySQL
  • SQL Server

Feature description

When the read/write splitting feature is enabled, this operation is used to calculate system-assigned read weights. For more information about custom read weights, see DescribeDBInstanceNetInfo .


Before you call this operation, make sure that the following requirements are met:

  • If the instance runs MySQL, the instance uses a shared proxy.

  • The instance runs one of the following MySQL versions and RDS editions:

    • MySQL 5.7 on RDS High-availability Edition (with local disks)
    • MySQL 5.6
    • SQL Server on RDS Cluster Edition


OpenAPI Explorer automatically calculates the signature value. For your convenience, we recommend that you call this operation in OpenAPI Explorer.

Authorization information

The following table shows the authorization information corresponding to the API. The authorization information can be used in the Action policy element to grant a RAM user or RAM role the permissions to call this API operation. Description:

  • Operation: the value that you can use in the Action element to specify the operation on a resource.
  • Access level: the access level of each operation. The levels are read, write, and list.
  • Resource type: the type of the resource on which you can authorize the RAM user or the RAM role to perform the operation. Take note of the following items:
    • The required resource types are displayed in bold characters.
    • If the permissions cannot be granted at the resource level, All Resources is used in the Resource type column of the operation.
  • Condition Key: the condition key that is defined by the cloud service.
  • Associated operation: other operations that the RAM user or the RAM role must have permissions to perform to complete the operation. To complete the operation, the RAM user or the RAM role must have the permissions to perform the associated operations.
OperationAccess levelResource typeCondition keyAssociated operation
  • DBInstance
  • rds:ResourceTag

Request parameters


The primary instance ID. You can call the DescribeDBInstances operation to query the instance ID.


Response parameters


The response parameters.


The request ID.

Itemsobject []

An array that consists of information about the system-assigned read weight.


The latency at which the read-only instances replicate data. The read-only instances replicate data from the primary instance at the latency that is specified by the ReadonlyInstanceSQLDelayedTime parameter. Unit: seconds.


The read weight that the system calculates in real time for the instance.


The type of the instance. Valid values:

  • Master: primary instance
  • Readonly: read-only instance

The instance ID



Sample success responses


  "RequestId": "C816A4BF-A6EC-4722-95F9-2055859CCFD2",
  "Items": {
    "DBInstanceWeight": [
        "ReadonlyInstanceSQLDelayedTime": "30",
        "Weight": "100",
        "DBInstanceType": "Master",
        "DBInstanceId": "rm-uf6wjk5xxxxxxx"

Error codes

HTTP status codeError codeError messageDescription
403IncorrectDBInstanceTypeCurrent DB instance engine and type does not support operations.The operation failed. The operation is not supported for the database engine of the RDS instance.
403IncorrectDBInstanceConnTypeCurrent DB instance conn type does not support this operation.The operation is not supported for the connection type of the RDS instance.
403IncorrectDBTypeThe current DB type does not support this operation.The operation failed. The operation is not supported by the database engine of the RDS instance. Specify a different database engine.
404InvalidDBInstanceName.NotFoundInvalid DBInstanceId NotFound.The instance ID cannot be found.
404IncorrectDBInstanceLockModeCurrent DB instance lock mode does not support this operation.The operation failed. The RDS instance is locked.
404InvalidDBInstanceClass.NotFoundSpecified DB instance class is not found.The configuration or the instance type cannot be found or has been discontinued. Specify a different configuration or a different instance type.

For a list of error codes, visit the Service error codes.

Change history

Change timeSummary of changesOperation
2022-08-12The response structure of the API has changedsee changesets
Change itemChange content
Output ParametersThe response structure of the API has changed.