Massively Parallel SortMerge Joins in Main Memory MultiCore Database Systems
Two emerging hardware trends will dominate the database system technology in the near future: increasing main memory capacities of several TB per server and massively parallel multi-core processing. Many algorithmic and control techniques in current database technology were devised for disk-based systems where I/O dominated the performance. In this paper, the authors take a new look at the well-known sort-merge join which, so far, has not been in the focus of research in scalable massively parallel multi-core data processing as it was deemed inferior to hash joins. They devise a suite of new Massively Parallel Sort-Merge (MPSM) join algorithms that are based on partial partition-based sorting.