Abstract

The development of a cost model for predicting the performance of spatial joins has been identified in the literature as an important and difficult problem. In this paper, we present the first cost model that can predict the performance of spatial joins using R-trees. Based on two existing R-trees (join targets), our model first estimates the number of expected I/Os for the join process by assuming a zero buffer size. Our method for this estimation extends the cost model for R-tree window queries (developed by Kamel and Faloutsos and by Pagel et al.) to also handle spatial joins (which are more complex). In the context of spatial join processing, this number of zero-buffer expected I/Os is not practical for performance prediction in a buffered environment. To model the buffer impact, we use an (exponential) distribution function to measure the probability that a bufferless I/O would cause a page fault in a buffered environment. Based on this probability and the zero-buffer expected I/O...

Citations