HIGH LEVEL PERFORMANCE ESTIMATE OF RELATIONAL QUERIES
Harry K. T. Wong · University of North Texas Digital Library (University of North Texas) · 1980
Performance estimate of queries is a necessary part of any efficient database design methodology. A high-level performance estimator for relational queries is presented which is different from conventional evaluators such as SYSTEM R (Selinger, Proc. SIGMOD 79) in that performance is predicted without the details of the low-level constructs such as links and indices. Rather, abstractions and reasonable assumptions of these low-level constructs are used in a set of formulas to estimate the performance of a set of queries against a schema. The major results of the paper are the realization and motivation of the need of high-level performance estimators of this kind, and a fast way to estimate the cost of N-way joins. The second result is interesting in that the algorithm for N-way joins is found to be similar to matrix multiplication optimization, with straightforward extensions.