Resource Classes in Distributed Queries

Resources that are available to DML operations on databases of the local XPS server instance use the resource class parameters settings that are in effect for the current database to which the session was connected when the operation began.

In a cross-server distributed query that accesses database objects of the local XPS server instance and objects of one or more other XPS servers, the available resources can vary across the participating database servers:

• The portion of the query running locally is restricted by the DS_CLASS parameters of the current session in local DML operations.
• For portions of a cross-server DML operation that are executed by another XPS server that implements resource classes, the remote server attempts to apply the DS_CLASS of the same name, if one exists. If no resource class has the same name, the remote server applies the parameter values of its DEFAULT resource class. (Note, however, that the remote server might apply completely different values for CLASS_DS_MEM_QUOTA and CLASS_DS_MAX_QUERIES to a class that has the same name as a resource class on the local server.)
• Resource class parameters have no effect on any portions of distributed DML operations that are performed by database servers that do not support resource classes.

Resource class parameters are not visible to database servers that do not support resource classes.