Apparatus, system, and method for performing fast approximate computation of statistics on query expressions
US7593931B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 2007 |
| Grant date | Sep 22, 2009 |
| Priority date | — |
| Expiry date | Oct 18, 2027 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99934
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An apparatus, system, and method are disclosed for performing fast approximate computation of statistics on query expressions in order to improve query optimization within a database management system by accurately and quickly estimating the sizes of intermediate query results. This is accomplished by analyzing a query for join instruction and identifying a fact table and a dimension table within those join instructions. Then, frequency statistics corresponding to distinct values of within the fact table are retrieved from a catalog table. Those frequency statistics are used in combination with a full scan of the dimension table accurately and quickly estimate frequency statistics for an expected join between the fact table and dimension table. The estimated frequency statistics corresponding to the expected join may then be used in such operations as query optimization.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.