System for adapting query optimization effort to expected execution time
US5301317A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 27, 1992 |
| Grant date | Apr 5, 1994 |
| Priority date | — |
| Expiry date | Apr 27, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99932
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system for the automatic adjustment of resources devoted to query optimization according to estimated query execution time. The disclosed system permits the query optimizer to automatically trade off the time spent estimating the execution cost of alternate query execution plans against the potential savings in execution time that one of those alternate plans may yield. The number of alternate plans considered is adjusted by selecting compile-time parameters and heuristic criteria for limiting the primitive database operators used in the alternate plans, thereby establishing a new search space. The parameters and criteria are adjusted according to the estimate of execution cost for the optimal plan from a first search space. The first search space may be relatively small and quickly evaluated. Evaluation of larger subsequent search spaces is optional according to an automatic thresholding process of the disclosed system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.