Aggregations design in database services

摘要

A method, apparatus, and software are disclosed for efficient selection of aggregations, or summaries of data in a database, for answering queries. Benefit/cost ratings are maintained for possible aggregations and are used in determining which aggregations should be selected. Lists of candidate and selected aggregations are also maintained, and aggregations are moved between these lists based on their benefit/cost ratings. These ratings are adjusted as aggregations are moved between the lists.