The IDTSDataPumpTransform interface is retrieved and its methods are called by the data pump to perform individual transformations. All custom transformation COM objects must support the IDTSDataPumpTransform interface.
An instance of the IDTSDataPumpTransform interface is created by the ServerClsid being passed to IDTSDataPump::AddTransform. ServerParameters allows the data pump consumer to create a single instance of an IDTSDataPumpTransform implementation and pass it to multiple IDTSDataPump::AddTransform calls. This is used by custom transformation servers and can be used for internal operations as performing aggregations. The custom transformation server should track this using the pvTransformServerData parameter to optimize operations such as AddVariable, OnRowComplete, and so on.