Query Size Estimation using Systematic Sampling

Banchong Harangsri, John Shepherd, Anne H.H. Ngu

International Symposium on Cooperative Database Systems for Advanced Applications,
Heian Shrine, Kyoto, December 1996.

(Compressed Postscript ... 80KB)


In this paper, we propose a new approach to the estimation of query size for select and join operations. The technique, which we have called "systematic sampling", is a novel variant of the sampling approach, which sorts the relation before sampling, and which maintains a summary relation to improve run-time performance. We compare the method to a number of existing methods to tackle the problem of query size estimation, and demonstrate, with extensive experimental results, that it performs better than existing approaches over a wide range of data sets.

Keys: Databases, Query optimisation, Selectivity estimation, Sampling


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