Sharing snapshots for consistent reads
US5956731A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1997 |
| Grant date | Sep 21, 1999 |
| Priority date | — |
| Expiry date | Apr 23, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99953
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for supplying data from a database to a group of transactions is provided. A value is maintained for the group of transactions. The value indicates a target snapshot of the database. When a transaction within the group of transactions accesses a data item, it is determined whether the transaction can use the target snapshot. If the transaction can use the target snapshot, then the transaction is supplied a version of the data item that belongs to the target snapshot. If the transaction cannot use the target snapshot, then the transaction is supplied a version of the data item other than the version of the data item that belongs to the target snapshot. Trying to supply data from the same snapshot to all of the transactions in the group increases the likelihood that the transactions will be able to use the same version of any given data item. Consequently, fewer reconstruction operations will have to be performed, and dynamic memory is less likely to become filled with different versions of the same data items.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.