Optimizing database queries using reusable subqueries
US9582539B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 2013 |
| Grant date | Feb 28, 2017 |
| Priority date | — |
| Expiry date | Aug 11, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/2453
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A database system optimizes database queries that comprise subqueries. The database system factors out computation from two or more subqueries to a reusable subquery. The reusable subquery returns a result set. The subqueries are rewritten to use the result set and the database query modified to use the rewritten subqueries. The modified database query performs efficiently since the result set is computed only once for each subquery that uses the reusable query. The database system also composes nested subqueries that compute aggregate values. The database system identifies an inner subquery nested within an outer subquery, each subquery computing an aggregate value. The database system determines a new aggregate function corresponding to a composition of aggregate functions of the inner and the outer queries. The database system determines a composed query using the inner query with the outer query. The composed query uses the new aggregate function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.