Title
Handling redundant processing in OBDA query execution over relational sources
Abstract
Redundant processing is a key problem in the translation of initial queries posed over an ontology into SQL queries, through mappings, as it is performed by ontology-based data access systems. Examples of such processing are duplicate answers obtained during query evaluation, which must finally be discarded, or common expressions evaluated multiple times from different parts of the same complex query. Many optimizations that aim to minimize this problem have been proposed and implemented, mostly based on semantic query optimization techniques, by exploiting ontological axioms and constraints defined in the database schema. However, data operations that introduce redundant processing are still generated in many practical settings, and this is a factor that impacts query execution. In this work we propose a cost-based method for query translation, which starts from an initial result and uses information about redundant processing in order to come up with an equivalent, more efficient translation. The method operates in a number of steps, by relying on certain heuristics indicating that we obtain a more efficient query in each step. Through experimental evaluation using the Ontop system for ontology-based data access, we exhibit the benefits of our method.
Year
DOI
Venue
2021
10.1016/j.websem.2021.100639
Journal of Web Semantics
Keywords
DocType
Volume
Query translation,Data integration,Ontology-based data access,Ontop
Journal
68
ISSN
Citations 
PageRank 
1570-8268
0
0.34
References 
Authors
0
2
Name
Order
Citations
PageRank
Dimitris Bilidas1888.14
Manolis Koubarakis22790322.32