Substituting parameter markers for literals in database query language statement to promote reuse of previously generated access plans
US7289978B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 2003 |
| Grant date | Oct 30, 2007 |
| Priority date | — |
| Expiry date | Feb 7, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99932
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method, computer program product and computing device for promoting reuse of previously generated access plans are disclosed. SQL statements containing literals are amended so as to substitute a parameter marker for each literal. Amended statements are provided to the DBMS along with parameters including the substituted literals and a substitution indicator indicating that the substitution has been performed. The DBMS assesses the soundness of the substitutions that are performed. Soundness may be measured in terms of the semantic correctness of the amended statement and the likelihood that the literal substitution will improve DBMS efficiency. If a substitution is unsound, the DBMS may obtain and optimize the original version of the amended SQL statement. Otherwise, the amended statement is optimized. Advantageously, SQL statements originally differing only in the value of one or more literals may become functionally equivalent, and the reuse of cached, previously generated access plans is thus promoted.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.