The join algorithms on a shared-memory multiprocessor database machine

The authors develop and present a large set of parallel algorithms for implementing the join operation on a shared-memory multiprocessor database machine. The development of these algorithms follows a structured approach. The major steps involved in the processing of the join operation by the machine are first identified. Then, alternative join algorithms are constructed by concatenating the different ways of performing these steps. A study of the performance of the proposed algorithms is presented. This study shows, among other things, that for a given hardware configuration there is not just one overall best performing join algorithm, but rather different algorithms score the best performance, depending on the characteristics of the data participating in the join operation