Multi-join on parallel processors

A preliminary evaluation of some multijoin strategies and their performances on parallel hardware is described. The hardware used was a Sequent (under Unix) with 11 usable processors, each with shared and private primary memory. A multijoin was broken down into a series of single joins which were then allocated to clusters, each cluster being a collection of parallel processors. The results of single joins, which were studied by both binary search and hash-merge techniques, were then further processed as necessary. The evaluation was conducted varying a number of parameters, such as cluster size, tuple size and cardinality. The comparative results were plotted. The study highlights the importance of a number of factors that influence the performance of a multijoin operation