System and method for reducing compile time in a top down rule based system using rule heuristics based upon the predicted resulting data flow
US6205441A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 1999 |
| Grant date | Mar 20, 2001 |
| Priority date | — |
| Expiry date | Mar 31, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99937
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention applies one or more pruning heuristics to the expression, the binding, and/or the substitute during a database query optimization process. The heuristics identify certain rules that can be eliminated by either not applying the rules and/or not implementing the rules for a given expression and context (if any) based upon one or more flow rates of the expression. The pruning heuristics can eliminate the application of rules based upon the flow rates of the binding or substitute, for example. Examples include (1) not applying (cutting) a MergeJoin rule for a join expression when an inner table is small enough to be stored in a memory space that is allocated for a HashJoin; (2) not applying implementation rules on the substitute of a left-shift rule for an expression if the resulting input data flow rate from the left child of the join is significantly larger in the substitute than in the binding; (3) not applying the join to TSJ (tuple substitute join) rule if the data flow output of the join expression is significantly larger than the data flow input from the inner child of the join expression; or (4) not applying implementation rules on the substitute join expr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.