Techniques for reducing the number of snapshots of a database

Patent 5956713 Issued on September 21, 1999. Estimated Expiration Date:

April 23, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Multiple version database concurrency control system
Patent #: 5280612
Issued on: 01/18/1994
Inventor: Lorie, et al.

Intelligent page store for concurrent and consistent access to a database by a transaction processor and a query processor
Patent #: 5317731
Issued on: 05/31/1994
Inventor: Dias, et al.

Simplified relational data base snapshot copying Patent #: 5440735
Issued on: 08/08/1995
Inventor: Goldring

Inventors

Application

No. 838967 filed on 04/23/1997

US Classes:

707/8, Concurrency (e.g., lock management in shared database)707/201, Coherency (e.g., same view to multiple users)707/203Version management

Examiners

Primary: Lintz, Paul R.

Attorney, Agent or Firm

McDermott, Will & Emery

International Class

G06F 017/30

Abstract

A method and apparatus for reducing the number of snapshots in use within a database is provided. A transaction that accesses one or more data items in a database is assigned to a snapshot of the database when the transaction completes execution. At that time, it is determined whether a first snapshot includes any transactions that updated the one or more data items. If the first snapshot includes any transactions that updated the one or more data items, then the transaction is assigned to a different snapshot that includes the first snapshot. If the first snapshot does not include any transactions that updated the one or more data items, then the transaction is assigned to the first snapshot. This technique allows multiple transactions to the same snapshot, consequently reducing the actual number of snapshots of the database.