System and method for database query optimization
US5819255A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 27, 1996 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Dec 27, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99936
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system and method for optimizing a database query with improved performance enhancements is herein disclosed. The database query consists of one or more logical expressions. Through the repeated application of one or more rules, the logical expressions are transformed into physical expressions and in some cases, execution plans that implement the database query. Each expression has associated with it a set of group attributes that specifies its characteristic inputs and outputs and a cost that estimates the computational expense for executing the expression. The group attributes are used to categorize similar expressions into groups that are stored in a search data structure. They are also used to track duplicate expressions. The cost associated with an expression is used to guide the search process to consider those expressions that will produce low cost plans. The cost is estimated in accordance with a six-fold criteria with each criterion weighted to account for the context of the expression and the application's particular computing environment. The query optimizer is rule-based including transformation and implementation rules that are used to perform transformations on the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.