FeatureSet Element (DTA)
Contains the physical design structures (indexes or indexed views) that you would like Database Engine Tuning Advisor to use during analysis.
Data type and length
string, no maximum length.
Use one of these values with this element.
Required once for each TuningOptions element, unless the DropOnlyMode element is used. If DropOnlyMode is used, you cannot use FeatureSet. These elements are mutually exclusive.