The selectivity factor of relational operations is a critical parameter for determining the cost function of query processing. Good estimates of these parameters allow the optimizers to choose the least expensive path in the query execution. A method for estimating the join and projection selectivity factors based on the orthogonal polynomial series is presented. Experimental results on real data are also reported which show the good performance of the approach.
Estimating Join and Projection Selectivity Factors
LEFONS, Ezio;TANGORRA, Filippo
2009-01-01
Abstract
The selectivity factor of relational operations is a critical parameter for determining the cost function of query processing. Good estimates of these parameters allow the optimizers to choose the least expensive path in the query execution. A method for estimating the join and projection selectivity factors based on the orthogonal polynomial series is presented. Experimental results on real data are also reported which show the good performance of the approach.File in questo prodotto:
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