A Query Processing Algorithm for Distributed Relational Database Systems
Csaba J. Egyhazy · The Computer Journal · 1988
A heuristic-based algorithm is presented which determines the combination of relational algebra operators and their corresponding processing sites in the network, in response to a query or class of queries. A technique is proposed for the computation of the resulting relation size after a projection, a selection and a join on non-key attributes or the estimation of the resulting relation size after a join on key attributes. This technique supplies the algorithm with the necessary input for determining which relations are to be sent across the network for processing. First, we describe how this algorithm differs from what is reported, in the literature. Second, the algorithm is formulated and, third its implementation is described through an example. Finally, we summarise our findings and discuss future work.