Technical Perspective: From Binary Join to Free Join

Abstract

Most queries access data from more than one relation, which makes joins between relations an extremely common operation. In many cases the execution time of a query is dominated by the processing of the involved joins. This observation has led to a wide range of techniques to speed up join processing like, e.g. efficient hash joins, bitmap filters to eliminate non-joining tuples early on, blocked lookups to hide cache latencies, and many others.