Streaming joins in constrained memory environments
US9880769B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 5, 2015 |
| Grant date | Jan 30, 2018 |
| Priority date | — |
| Expiry date | Jul 13, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/21
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Large amounts of memory can be consumed in streaming joins because events from one stream are held in memory while waiting for matching events from a second stream. Memory needs can be reduced by analyzing the join condition to determine the bounds on the time discrepancy between events in the two streams. When it is determined that an event from one stream must occur prior to the matching event from the other stream, the later-arriving stream data can be ingested with an intentional delay. When it is determined that regardless of input received from a first stream, no output will be produced when there is no input from the second stream, pulling data from the first stream can cease. A multi-stage join plan can be employed so that a less busy stream can be scanned with increasing amounts of intentional delay. Only unmatched data is stored.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.