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AssigneeInternational Business Machines Corporation
InventorsPeter J. Haas, John E. Lumby, Calisto P. Zuzarte
Estimating the term…
The estimate of the selectivity of a HAVING clause in an SQL query is carried out within a specified time constraint by determining a selectivity estimate for each member in a sample set of group sizes for the HAVING clause using a probabilistic model based on an assumed value distribution. The selectivity estimates for the groups in the sample set are used to interpolate estimates for all possible group sizes and the estimates are combined based on an assumed known group size distribution to provide an estimation of the selectivity for the HAVING clause. Different selectivity estimating approaches are used for each group size based on available time for estimating and on the estimated time to complete the estimate using different techniques.
A method for estimating a selectivity of a HAVING clause in an SQL query, the method comprising the steps of:
A system for estimating a selectivity of a HAVING clause in an SQL query, the system comprising:
A computer readable medium containing program instructions for estimating a selectivity of a HAVING clause in an SQL query, the program instructions comprising the steps of:
Dependencies are inferred from the claim text.