Towards creating specialised integrity checks through partial evaluation of meta-interpreters

Abstract

Integrity constraints are useful for the specification of deductive databases, as well as for inductive and abductive logic programs. Verifying integrity constraints upon updates is a major efficiency bottleneck and specialised methods have been developed to speedup this task. They can however still incur a considerable overhead. In this paper we propose a solution to this problem by using partial evaluation to pre-compile the integrity checking for certain update patterns. The idea being, that a lot of the integrity checking can already be performed given an update pattern without knowing the actual, concrete update. In order to achieve the pre-compilation, we write the specialised integrity checking as a meta-interpreter in logic programming. This meta-interpreter incorporates the knowledge that the integrity constraints were not violated prior to a given update and uses a technique to lift the ground representation to the non-ground one for resolution. By partially evaluating this meta-interpreter for certain transaction patterns, using a sophisticated partial evaluation technique presented in earlier work, we are able to automatically obtain very efficient specialised update procedures, executing, for instance, substantially faster than the original meta-interpreter. Creating Specialised Integrity Checks Through Partial Evaluation of Meta-Interpreters Michael Leuschel and Danny De Schreyey Department of Computer Science, K.U. Leuven Celestijnenlaan 200A, B-3001 Heverlee, Belgium e-mail: fmichael,dannydg@cs.kuleuven.ac.be Tel.:++32(0)16-32 7555 Fax:++32(0)16-32 7996 July 10, 1996 Abstract Integrity constraints are useful for the speci cation of deductive databases, as well as for inductive and abductive logic programs. Verifying integrity constraints upon updates is a major e ciency bottleneck and specialised methods have been developed to speedup this task. They can however still incur a considerable overhead. In this paper we propose a solution to this problem by using partial evaluation to precompile the integrity checking for certain update patterns. The idea being, that a lot of the integrity checking can already be performed given an update pattern without knowing the actual, concrete update. In order to achieve the pre-compilation, we write the specialised integrity checking as a meta-interpreter in logic programming. This meta-interpreter incorporates the knowledge that the integrity constraints were not violated prior to a given update and uses a technique to lift the ground representation to the non-ground one for resolution. By partially evaluating this meta-interpreter for certain transaction patterns, using a sophisticated partial evaluation technique presented in earlier work, we are able to automatically obtain very e cient specialised update procedures, executing, for instance, substantially faster than the original meta-interpreter.