In Virtual DataPort, to delegate function to source you should check the Delegate properties box in the ‘Source Configuration’ tab of the data source and add the function to the list.
For example, I have oracle Data Source with a function called PREDICTION_COST, I would do the following steps,
* Select the Data Source and click on Configuration > Source Configuration.
* In Source Configuration, check the Delegate analytic function list and add the ‘PREDICTION_COST’ function in the list.
* Now I can push down the query to Data source instead of performing the operation in the Virtual layer.
Just keep in mind that when you uncheck the “Delegate properties ” box, you can only use the default functions list defined for that specific adapter and operation are performed in the Virtual Layer.
For more information, you can refer to the [Analytic Functions](https://community.denodo.com/docs/html/browse/7.0/vdp/vql/appendix/syntax_of_condition_functions/analytic_functions_window_functions) of the Virtual DataPort VQL Guide and [Data Source Configuration Properties](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/creating_data_sources_and_base_views/data_source_configuration_properties/data_source_configuration_properties) of the Virtual DataPort Administration Guide.
Hope this helps!