Formulating global statistics for distributed databases
US8972378B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 2012 |
| Grant date | Mar 3, 2015 |
| Priority date | — |
| Expiry date | Oct 22, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F16/24554
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention extends to methods, systems, and computer program products for formulating global statistics for parallel databases. In general, embodiments of the invention merge (combine) information in multiple compute node level histograms to create a global histogram for a table that is distributed across a number of compute nodes. Merging can include aligning histogram step boundaries across the compute node histograms. Merging can include aggregating histogram step-level information, such as, for example, equality rows and average range rows (or alternately equality rows, range rows, and distinct range rows), across the compute node histograms into a single global step. Merging can account for distinct values that do not appear at one or more compute nodes as well as distinct values that are counted at multiple compute nodes. A resulting global histogram can be coalesced to reduce the step count.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.