Method and apparatus for virtual memory mapping and transaction management in an object-oriented database system

• US 20050120080A1
• Filed: 09/16/2004
• Published: 06/02/2005
• Est. Priority Date: 03/22/1991
• Status: Active Grant

• Current Assignee: Objectstore Incorporated
• Original Assignee: Daniel L. Weinreb, Sam J. Haradhvala
• Inventors: Weinreb, Daniel L., Haradhvala, Sam J.
• Granted Patent: US 7,290,113 B2
• Time in Patent Office: Days
• US Class Current: 709/203
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 12/0815 Cache consistency protocols
• CPC Class Codes: G06F 12/10 Address translation
• CPC Class Codes: G06F 12/1072 Decentralised address translation, e.g. in distributed shared memory systems
• CPC Class Codes: G06F 9/4493 Object persistence
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

An apparatus and method are provided for virtual memory mapping and transaction management in an object-oriented database system having permanent storage for storing data in at least one database, at least one cache memory for temporarily storing data, and a processing unit which runs application programs which request data using virtual addresses. The system performs data transfers in response to memory faults resulting from requested data not being available at specified virtual addressed and performs mapping on data in cache memory. The data in the database may include pointers containing persistent addresses, which pointers are relocated between persistent addresses and virtual addresses. When a data request is made, either for read or write, from a given client computer in a system, other client computers in the system are queried to determine if the requested data is cached and/or locked in a manner inconsistent with the requested use, and the inconsistent caching is downgraded or the transfer delayed until such downgrading can be performed.

Claims

1. An apparatus for virtual memory mapping and transaction management for an object-oriented database system having at least one permanent storage means for storing data in at least one database, at least one cache memory for temporarily storing data addressed by physical addresses, and a processing unit, the processing unit including means for requesting data utilizing virtual addresses to access said data in the cache memory, means for mapping virtual addresses to physical addresses, and means for detecting when data requested by the requesting means is not available at the virtual address utilized by the requesting means, said apparatus comprising:

means operative in response to a detection by said detecting means for determining if the requested data is in the cache memory,

means for transferring the requested data from the permanent storage means to the cache memory responsive to a determination by said determining means that the requested data is not in the cache memory, and

means operative when requested data is in the cache memory for instructing the means for mapping to map the virtual addresses of the requested data to the physical addresses of the data in the cache memory.

2-117. -117. (canceled)