TY - JOUR
T1 - On the convergence of query evaluation
AU - Afrati, Foto
AU - Papadimitriou, Christos H.
AU - Papageorgiou, George
AU - Roussou, Athena
AU - Sagiv, Yehoshua
AU - Ullman, Jeffrey D.
PY - 1989/4
Y1 - 1989/4
N2 - We propose a "sideways information passing" method for evaluating Horn clause queries in the presence of monotonicity constraints on the database relations. We give a necessary and sufficient condition for its convergence and show that testing for the condition is polynomial when the arity of the relations is bounded, and PSPACE-complete otherwise. We also prove a related condition for the case of downward finite domains (e.g., Herbrand universes), thus improving an algorithm by Naish for a class of Prolog programs.
AB - We propose a "sideways information passing" method for evaluating Horn clause queries in the presence of monotonicity constraints on the database relations. We give a necessary and sufficient condition for its convergence and show that testing for the condition is polynomial when the arity of the relations is bounded, and PSPACE-complete otherwise. We also prove a related condition for the case of downward finite domains (e.g., Herbrand universes), thus improving an algorithm by Naish for a class of Prolog programs.
UR - http://www.scopus.com/inward/record.url?scp=45349113220&partnerID=8YFLogxK
U2 - 10.1016/0022-0000(89)90006-8
DO - 10.1016/0022-0000(89)90006-8
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AN - SCOPUS:45349113220
SN - 0022-0000
VL - 38
SP - 341
EP - 359
JO - Journal of Computer and System Sciences
JF - Journal of Computer and System Sciences
IS - 2
ER -