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Covers of Query Results

Authors Ahmet Kara, Dan Olteanu

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Ahmet Kara
Dan Olteanu

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Ahmet Kara and Dan Olteanu. Covers of Query Results. In 21st International Conference on Database Theory (ICDT 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 98, pp. 16:1-16:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)
https://doi.org/10.4230/LIPIcs.ICDT.2018.16

Abstract

We introduce succinct lossless representations of query results called covers. They are subsets of the query results that correspond to minimal edge covers in the hypergraphs of these results. We first study covers whose structures are given by fractional hypertree decompositions of join queries. For any decomposition of a query, we give asymptotically tight size bounds for the covers of the query result over that decomposition and show that such covers can be computed in worst-case optimal time up to a logarithmic factor in the database size. For acyclic join queries, we can compute covers compositionally using query plans with a new operator called cover-join. The tuples in the query result can be enumerated from any of its covers with linearithmic pre-computation time and constant delay. We then generalize covers from joins to functional aggregate queries that express a host of computational problems such as aggregate-join queries, in-database optimization, matrix chain multiplication, and inference in probabilistic graphical models.
Keywords
  • factorized database
  • fractional hypertree decomposition
  • functional aggregate query
  • minimal edge cover
  • query plan

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References

  1. Serge Abiteboul, Richard Hull, and Victor Vianu. Foundations of Databases. Addison-Wesley, 1995. Google Scholar
  2. Mahmoud Abo-Khamis, Hung Ngo, XuanLong Nguyen, Dan Olteanu, and Maximilian Schleich. In-database learning with sparse tensors. In PODS, 2018. To appear. Google Scholar
  3. Alfred V. Aho, John E. Hopcroft, and Jeffrey D. Ullman. The Design and Analysis of Computer Algorithms. Addison-Wesley, 1974. Google Scholar
  4. Albert Atserias, Martin Grohe, and Dániel Marx. Size bounds and query plans for relational joins. SIAM J. Comput., 42(4):1737-1767, 2013. Google Scholar
  5. Guillaume Bagan, Arnaud Durand, and Etienne Grandjean. On acyclic conjunctive queries and constant delay enumeration. In CSL, pages 208-222, 2007. Google Scholar
  6. Nurzhan Bakibayev, Tomás Kociský, Dan Olteanu, and Jakub Závodnỳ. Aggregation and ordering in factorised databases. PVLDB, 6(14):1990-2001, 2013. Google Scholar
  7. Catriel Beeri, Ronald Fagin, David Maier, and Mihalis Yannakakis. On the desirability of acyclic database schemes. J. ACM, 30(3):479-513, 1983. Google Scholar
  8. Ashok K. Chandra and Philip M. Merlin. Optimal implementation of conjunctive queries in relational data bases. In STOC, pages 77-90, 1977. Google Scholar
  9. Hugh Darwen, C. J. Date, and Ronald Fagin. A normal form for preventing redundant tuples in relational databases. In ICDT, pages 114-126, 2012. Google Scholar
  10. Ronald Fagin. Normal forms and relational database operators. In SIGMOD, pages 153-160, 1979. Google Scholar
  11. Ronald Fagin, Phokion G. Kolaitis, and Lucian Popa. Data exchange: Getting to the core. ACM Trans. Datab. Syst., 30(1):174-210, 2005. Google Scholar
  12. Georg Gottlob. Computing cores for data exchange: New algorithms and practical solutions. In PODS, pages 148-159, 2005. Google Scholar
  13. Georg Gottlob, Zoltán Miklós, and Thomas Schwentick. Generalized hypertree decompositions: NP-hardness and tractable variants. J. ACM, 56(6):30:1-30:32, 2009. Google Scholar
  14. Martin Grohe and Dániel Marx. Constraint solving via fractional edge covers. ACM Trans. Alg., 11(1):4, 2014. Google Scholar
  15. Claudio Gutierrez, Carlos Hurtado, and Alberto O. Mendelzon. Foundations of semantic web databases. In PODS, pages 95-106, 2004. Google Scholar
  16. Pavol Hell and Jaroslav Nešetřil. The core of a graph. Discrete Mathematics, 109(1):117-126, 1992. Google Scholar
  17. Ahmet Kara and Dan Olteanu. Covers of query results. CoRR, abs/1709.01600, 2017. URL: http://arxiv.org/abs/1709.01600.
  18. Mahmoud Abo Khamis, Hung Q. Ngo, and Atri Rudra. FAQ: questions asked frequently. In PODS, pages 13-28, 2016. Google Scholar
  19. E. Lawler. Combinatorial Optimization: Networks and Matroids. Dover Publications, 2001. Google Scholar
  20. Dániel Marx. Approximating fractional hypertree width. ACM Trans. Alg., 6(2):29:1-29:17, 2010. Google Scholar
  21. Hung Q. Ngo, Christopher Ré, and Atri Rudra. Skew strikes back: new developments in the theory of join algorithms. SIGMOD Record, 42(4):5-16, 2013. Google Scholar
  22. Dan Olteanu and Maximilian Schleich. Factorized Databases. SIGMOD Record, 45(2):5-16, 2016. Google Scholar
  23. Dan Olteanu and Jakub Závodnỳ. Size bounds for factorised representations of query results. ACM Trans. Datab. Syst., 40(1):2:1-2:44, 2015. Google Scholar
  24. Maximilian Schleich, Dan Olteanu, and Radu Ciucanu. Learning Linear Regression Models over Factorized Joins. In SIGMOD, pages 3-18, 2016. Google Scholar
  25. Luc Segoufin. Constant delay enumeration for conjunctive queries. SIGMOD Record, 44(1):10-17, 2015. Google Scholar
  26. Jeff Shute, Radek Vingralek, Bart Samwel, Ben Handy, Chad Whipkey, Eric Rollins, Mircea Oancea, Kyle Littlefield, David Menestrina, Stephan Ellner, John Cieslewicz, Ian Rae, Traian Stancescu, and Himani Apte. F1: A distributed SQL database that scales. PVLDB, 6(11):1068-1079, 2013. Google Scholar
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