Evaluation of database hierarchical cubes by nesting rollup operators associated with multiple groupings
US7035843B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 2002 |
| Grant date | Apr 25, 2006 |
| Priority date | — |
| Expiry date | Sep 1, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99933
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Methods are provided for efficiently evaluating database queries including multiple rollup operators. With the computation of grouping identifiers to distinguish grouping levels of each rollup operator, evaluation of database queries that include concatenation of rollup operators includes nesting of the rollup operators and includes the grouping identifiers as sorting keys for subsequent processing. Furthermore, to optimize the query evaluation process, the order in which the rollup operators are computed can be determined based on cardinalities that estimate the number of records generated by each rollup operator, and parallel evaluation can be utilized by partitioning data records between rollup operator processing stages based on the grouping keys associated with the rollup operators that are not being processed at the next stage. If the query includes an algebraic aggregate function, the algebraic function is represented as distributive functions, which are propagated through the evaluation stages and used to compute the algebraic function at the final rollup stage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.