Patents by Inventor Klaus B. Schiefer

Klaus B. Schiefer has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Computer program product for choosing largest selectivities among eligible predicates of join equivalence classes for query optimization
    Patent number: 5542073
    Abstract: A method for choosing join selectivities in a query optimizer in a relational database management system is disclosed which facilitates the estimation of join result sizes by a query optimizer in a relational database system, wherein a new relation R is to be joined with an intermediate relation I, and wherein the selectivity values for each eligible join predicate are known. The method has the steps of determining the equivalence classes for a plurality of join attributes and then computing for each relation an estimate of the cardinality and the number of distinct values in each attribute after all the local predicates have been included. These are used in further computation of join selectivities and join result sizes. The join predicates must then be processed by correctly choosing the join selectivities. The join result sizes can then be correctly calculated.
    Type: Grant
    Filed: August 1, 1995
    Date of Patent: July 30, 1996
    Assignee: International Business Machines Corporation
    Inventors: Klaus B. Schiefer, Arun N. Swami
  • Method for choosing largest selectivities among eligible predicates of join equivalence classes for query optimization
    Patent number: 5469568
    Abstract: A method for choosing join selectivities in a query optimizer in a relational database management system is disclosed which facilitates the estimation of join result sizes by a query optimizer in a relational database system, wherein a new relation R is to be joined with an intermediate relation I, and wherein the selectivity values for each eligible join predicate are known. The method has the steps of determining the equivalence classes for a plurality of join attributes and then computing for each relation an estimate of the cardinality and the number of distinct values in each attribute after all the local predicates have been included. These are used in further computation of join selectivities and join result sizes. The join predicates must then be processed by correctly choosing the join selectivities. The join result sizes can then be correctly calculated.
    Type: Grant
    Filed: January 7, 1993
    Date of Patent: November 21, 1995
    Assignee: International Business Machines Corporation
    Inventors: Klaus B. Schiefer, Arun N. Swami