Event-join optimization in temporal relational databases

Abstract

An Event-Join combines temporal join and outer-join properties into a single operation. It is mostly used to group temporal attributes of an entity into a single relation. In this paper, we motivate the need to support the efficient processing of event-joins, and introduce several optimization algorithms, both for a general data organization and for specialized organizations (sorted and append-only databases). For the append-only data-base we introduce a data structure that can improve the performance of event-joins as well as other queries. Finally, we evaluate the performance of the proposed algorithms.