Fusing global reporting aggregate computation with the underlying operation in the query tree for efficient evaluation

Abstract

Techniques herein generate a query plan that combines a global reporting aggregate calculation and an organizing operation. A method detects an organizing operation, a group aggregate function, and a global aggregate function within a database statement. The organizing operation specifies organizational activities such as grouping, joining, or sorting rows. The method generates an execution plan that specifies calculating all values in a single pass. For each row, the single pass applies the organizing operation and updates an access structure. The pass updates one of multiple cumulative group calculations based on the group aggregate function and updates a cumulative global calculation based on the global aggregate function. Each cumulative group calculation is associated with some of the access structure. Based on the access structure, result rows that satisfy the database statement are generated. Result rows contain a final result of each group calculation and a final result of the global calculation.