Towards relaxed selection and join queries over data streams

  • Authors:
  • Barbara Catania;Giovanna Guerrini;Maria Teresa Pinto;Paola Podestà

  • Affiliations:
  • Università di Genova, Italy;Università di Genova, Italy;Università di Genova, Italy;Università di Genova, Italy

  • Venue:
  • ADBIS'12 Proceedings of the 16th East European conference on Advances in Databases and Information Systems
  • Year:
  • 2012

Quantified Score

Hi-index 0.00

Visualization

Abstract

In a data stream management system, users may not be acquainted with the actual data arriving on the stream. Therefore, they may issue queries that return an empty result over several windows. In the relational context, relaxation skyline queries have been proposed as a solution to the so-called empty answer problem. Given a query composed of selection and join operations, a relaxation skyline query relies on the usage of a relaxation function (usually, a numeric function) to quantify the distance of each tuple (or pair of tuples in case of join) from the specified conditions and uses a skyline-based semantics to compute the answer. This paper addresses skyline-based relaxation over data streams. Relaxation skyline queries for selection and window-based join over data streams are defined and two different processing algorithms are proposed and experimentally compared.