AUTOMATICALLY DETERMINING OPTIMIZATION FREQUENCIES OF QUERIES WITH PARAMETER MARKERS

摘要

A method for automatically determining optimization frequencies of queries having one or more parameter markers. Bind value sets and associated measurement sets are obtained. Ouerv execution plans and associated execution costs for optimal query execution with a bind value set are determined. Bind value set pairs for execution plans with maximum distance in selectivity or cardinality are determined. Execution costs for all pairs of plans with maximum selectivity/cardinality distance are determined. An optimization frequency is selected based on differences between the determined execution costs and optimal execution costs. If none of the differences exceeds a predefined value, the query is optimized once. If at least one of the differences exceeds the predefined value, the query is reoptimized each time the query is executed.