Abstract
We present a technique for distributed evaluation of the deductive database language datalog, that is, prolog without function symbols. Datalog is both a powerful extension of relational database query languages like sql and a suitable language for constructing expert systems. Both of these types of applications tend to be computationally complex and to exhibit parallelism of the kinds known as Or parallelism and All-solutions And parallelism. We therefore expect large speedup by exploiting this parallelism.
The lack of function symbols ensures a finite model, in spite of presence of recursive clauses. We therefore discuss how to ensure termination while retaining completeness. Our distributed implementation uses a top/down interpretation strategy and is based on the problem-heap paradigm and dynamic load balancing. Tests show up to 14.2 times speedup, obtained on a Transputer network containing 16 Transputers.
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Jensen, L.S., Kaae, E.J. (1990). Distributed Evaluation of the Datalog Query Language. In: Tjoa, A.M., Wagner, R. (eds) Database and Expert Systems Applications. Springer, Vienna. https://doi.org/10.1007/978-3-7091-7553-8_29
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DOI: https://doi.org/10.1007/978-3-7091-7553-8_29
Publisher Name: Springer, Vienna
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