System, method, and computer-readable medium for optimizing processing of distinct and aggregation queries on skewed data in a database system
US8234268B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 2008 |
| Grant date | Jul 31, 2012 |
| Priority date | — |
| Expiry date | Dec 25, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/24532
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system, method, and computer-readable medium for optimization of query processing in a parallel processing system are provided. Skewed values and non-skewed values are treated differently to improve upon conventional DISTINCT and aggregation query processing. Skewed attribute values on which a DISTINCT selection or group by aggregation is applied are allocated entries in a hash table. In this manner, a processing module may consult the hash table to determine if a skewed attribute value has been encountered during the query processing in a manner that precludes repetitive redistribution of rows with highly skewed attribute values on which a DISTINCT selection or group by aggregation is applied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.