TOWARDS COMPACT OPERATOR TREES FOR QUERY INDEXING

Hagen Höpfner, Erik Buchmann

2008

Abstract

Application areas like semantic caches or update relevancy checks require query based indexing: They use an algebra representation of the query tree to identify reusable fragments of former query results. This requires compact query representations, where semantically equivalent (sub-)queries are expressed with identical terms. It is challenging to obtain such query representations: Attributes and relations can be renamed, there are numerous ways to formulate equivalent selection predicates, and query languages like SQL allow a wide range of alternatives for joins and nested queries. In this paper we present our first steps towards optimizing SQL-based query trees for indexing. In particular, we use both existing equivalence rules and new transformations to normalize the sub-tree structure of query trees. We optimize selection and join predicates, and we present an approach to obtain generic names for attributes and table aliases. Finally, we discuss the benefits and limitations of our intermediate results and give directions for future research.

Paper Citation

in Harvard Style

Höpfner H. and Buchmann E. (2008). TOWARDS COMPACT OPERATOR TREES FOR QUERY INDEXING . In Proceedings of the Third International Conference on Software and Data Technologies - Volume 3: ICSOFT, ISBN 978-989-8111-53-1, pages 174-179. DOI: 10.5220/0001888001740179

in Bibtex Style

@conference{icsoft08,
author={Hagen Höpfner and Erik Buchmann},
title={TOWARDS COMPACT OPERATOR TREES FOR QUERY INDEXING},
booktitle={Proceedings of the Third International Conference on Software and Data Technologies - Volume 3: ICSOFT,},
year={2008},
pages={174-179},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0001888001740179},
isbn={978-989-8111-53-1},
}

in EndNote Style

TY - CONF
JO - Proceedings of the Third International Conference on Software and Data Technologies - Volume 3: ICSOFT,
TI - TOWARDS COMPACT OPERATOR TREES FOR QUERY INDEXING
SN - 978-989-8111-53-1
AU - Höpfner H.
AU - Buchmann E.
PY - 2008
SP - 174
EP - 179
DO - 10.5220/0001888001740179