Data Structures for Dynamic Queries: An Analytical and Experimantal Evaluation.

Abstract

Dynamic Queries is a querying technique for doing range search on multi-key data sets. It is a direct manipulation mechanism where the query is formulated using graphical widgets and the results are displayed graphically preferably within 100 milliseconds. This paper evaluates four data structures, the multilist, the grid file, k-d tree and the quad tree used to organize data in high speed storage for dynamic queries. The effect of factors like size, distribution and dimensionality of data on the storage overhead and the speed of search is explored. Analytical models for estimating the storage and search overheads are presented, and verified to be correct by empirical data. Results indicate that multilists are suitable for small (few thousand points) data sets irrespective of the data distribution. For large data sets the grid files are excellent for uniformly distributed data, and trees are good for skewed data distributions. There was no significant difference in performance between the tree structures. (Also cross-referenced as CAR-TR-685) (Also cross-referenced as ISR-TR-93-73)