Parallel-Correctness and Containment for Conjunctive Queries with Union and Negation
Databases
2015-12-22 v1
Abstract
Single-round multiway join algorithms first reshuffle data over many servers and then evaluate the query at hand in a parallel and communication-free way. A key question is whether a given distribution policy for the reshuffle is adequate for computing a given query, also referred to as parallel-correctness. This paper extends the study of the complexity of parallel-correctness and its constituents, parallel-soundness and parallel-completeness, to unions of conjunctive queries with and without negation. As a by-product it is shown that the containment problem for conjunctive queries with negation is coNEXPTIME-complete.
Cite
@article{arxiv.1512.06246,
title = {Parallel-Correctness and Containment for Conjunctive Queries with Union and Negation},
author = {Gaetano Geck and Bas Ketsman and Frank Neven and Thomas Schwentick},
journal= {arXiv preprint arXiv:1512.06246},
year = {2015}
}