“…NN queries retrieve points of interest (POI), such as taxis and restaurants, closest to a query user [ 1 , 2 ], and RN queries retrieve POIs within a query distance [ 3 , 4 , 5 ]. Typically, location-based services (LBS), such as taxi-booking and ride-sharing services, use real-time spatial data to locate POIs close to the query user [ 6 , 7 , 8 , 9 , 10 ]. When multiple SP queries reach an LBS server simultaneously at peak times, if the SP queries are processed sequentially, it may not be possible to provide prompt responses to the query users.…”