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ApsaraDB RDS:CalculateDBInstanceWeight

Last Updated:May 29, 2023

You can call the CalculateDBInstanceWeight operation to query the system-assigned read weights of a primary instance and its read-only instances.

Operation 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:

  • The shared proxy feature is enabled for your ApsaraDB RDS for MySQL instance.

  • The instance must run one of the following database engine versions and RDS editions:

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

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
  • RDS
  • rds:ResourceTag

Request parameters


The ID of the primary instance.


Response parameters


The ID of the request.

Itemsobject []

An array that consists of the system-assigned read weights.


The threshold for the latency of data replication from the primary instance to the read-only instances. The read-only instances start to synchronize data from the primary instance after the time specified by the ReadonlyInstanceSQLDelayedTime parameter elapses. Unit: seconds.


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


The role of the instance. Valid values:

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

The ID of instance.



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 operation changes.
Change itemChange content
Output ParametersThe response structure of the API operation changes.