You can optimize a sort key for a precomputed sort.

Although users can sort on any record at any time, it is also possible to optimize a property or dimension for sort in Developer Studio. This mainly controls the generation of a precomputed sort, and secondarily enables the field to be returned in the API sort keys function. The sort key is an Oracle Commerce property or dimension that exists in the data set. It can be numeric, alphabetical, or geospatial, and determines the type of sort that occurs.