Exploring Load Balancing in Parallel Processing of Recursive Queries

Recent work on load balancing has connrmed its importance when one wants to achieve good performances during the actual evaluation of parallel database queries. Existing work mostly focuses on the join processing for parallel relational databases. We are interested here in more complex queries, such as recursive ones. The main diierence is that, in the latter case, the work due to a task cannot be previously determined and, consequently, no method can deene at the outset the tasks to be executed in parallel in order to balance the workload at each processor. We propose a dose-driven dynamic strategy that aims at obtaining an improved workload balance and better use of the available resources. We examine the applicability of our strategy with its specialization to the case of the transitive closure query. Preliminary computational results on randomly generated test problems illustrate the eeciency of the proposed method.