An O(n2) algorithm for fan-out free query optimization

  • Pratul Dublish
  • S. N. Maheshwari
Session 5 Database Theory
Part of the Lecture Notes in Computer Science book series (LNCS, volume 287)


An optimization algorithm for fan-out free queries, which form an untyped subclass of conjunctive queries, based on the implication graph technique is presented. The algorithm takes O(n2) steps where n is the size of the query. This algorithm subsumes all known algorithms for optimizing subclasses of fan-out free queries.


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  1. [ASU]
    A.V.Aho,Y.Sagiv and J.D.Ullman, Efficient optimization of a class of relational expressions, ACM Trans. on Database Systems, Vol. 4, No. 4, Dec 1979.Google Scholar
  2. [CM]
    A.K.Chandra and P.M.Merlin, Optimal implementation of conjunctive queries in relational databases, Proc. 9th Annual Symposium on Theory of Computation, May 1977.Google Scholar
  3. [DM]
    P.Dublish and S.N.Maheshwari, Optimization of a subclass of fan-out free queries, Unpublished Manuscript, Feb 1987.Google Scholar
  4. [JK]
    D.S.Johnson and A.Klug, Optimizing conjunctive queries that contain untyped variables, SIAM Journal on Computing, Vol. 12, No. 4, Nov 1983.Google Scholar
  5. [MM]
    B.N.S.Murthy and S.N.Maheshwari, Optimization of a class of relational expressions, Proc. 2nd Annual Conference on Foundations of Software Technology and Theoretical Computer Science, Bangalore, 1982.Google Scholar
  6. [MDM]
    B.N.S.Murthy, P.Dublish and S.N.Maheshwari, Some negative results on the optimization of conjunctive queries, Technical Report TR 85/01, Deptt. of Computer Science and Engg., IIT Delhi, Dec 1985.Google Scholar
  7. [Mai]
    D.Maier, The Theory of Relational Database, Computer Science Press, 1983.Google Scholar
  8. [Sag]
    Y.Sagiv, Quadratic algorithms for minimizing joins in restricted relational expressions, SIAM Journal on Computing, Vol. 12, No. 2, May 1983.Google Scholar
  9. [Ull]
    J.D.Ullman, Principles of Database Systems, Computer Science Press, 1982.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1987

Authors and Affiliations

  • Pratul Dublish
    • 1
  • S. N. Maheshwari
    • 1
  1. 1.Department of Computer Science & EngineeringIndian Institute of TechnologyDelhi New Delhi

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