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Query optimization in the CROQUE project

  • Andreas Heuer
  • Joachim Kröger
Object-Oriented Databases 4
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1134)

Abstract

This paper describes some concepts for the evaluation and optimization of ODMG-OQL queries. We present a logical object algebra for the internal representation of OQL queries. Different optimization techniques are sketched: factorization of common subexpressions, dependency-based optimization, and query rewriting. Afterwards, our physical algebra is presented and a complex example of the optimization process is given. We describe our implementation and the present investigations using search strategies to find the best execution plan. In contrast to previous studies on the evaluation of object-oriented queries, we use a logical and a physical algebra in the process of evaluation and optimization of OQL queries, thus achieving logical data independence. Other basic ideas of our work are the integration of different optimization techniques into one approach and the use of cost functions especially valid for the object-oriented database system ObjectStore.

Keywords

Query Evaluation Execution Plan Query Optimization Object Database Logical Algebra 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • Andreas Heuer
    • 1
  • Joachim Kröger
    • 1
  1. 1.CS Dept.University of RostockRostockGermany

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