Shedding strategies for optimizing join processing in spatial data streams

Abstract

A core component of any data stream query processing system is a shedding module, which must make decisions on which data to select and discard in order to make room for new incoming data. Although strategies for shedding have been studied in detail for systems that handle alphanumeric data, the subject has received very little attention in the area of spatial data stream query processing. This paper proposes several strategies for object shedding for spatial data stream query processing. These strategies employ spatial data properties, object properties and non-spatial properties in order to decide which objects to discard when space is needed. An evaluation and comparison versus a spatial stream query processing strategy which utilizes FIFO shedding shows that the shedding strategies which employ spatial data properties make the best choices which result in the highest accuracies overall and high accuracies in many cases.