Multiple Range Query Optimization

In order to answer efficiently range queries in 2-d R-trees, first we sort queries by means of a space filling curve, then we group them together, and finally pass them for processing. Initially, we consider grouping of pairs of requests only, and give two algorithms with exponential and linear complexity. Then, we generalize the linear method, grouping more than two requests per group. We evaluate these methods under different LRU buffer sizes, measuring the cache misses per query. We present experimental results based on real and synthetic data. The results show that careful query scheduling can improve substantially the overall performance of multiple range query processing.