System and method of maintaining functional client side data cache coherence

• US 20030217081A1
• Filed: 05/14/2002
• Published: 11/20/2003
• Est. Priority Date: 05/14/2002
• Status: Active Grant

• Current Assignee: Actian Corporation
• Original Assignee: Pervasive Software Incorporated (Actian Corporation)
• Inventors: Arnold, Richard, White, Ken, Lewis, Kevin, Jacob, Sunil, Sun, Chunsheng, Reinauer, Rob, Tan, Desmond
• Granted Patent: US 6,996,584 B2
• Time in Patent Office: Days
• US Class Current: 707/203
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: G06F 2212/154 Networked environment
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

The present invention provides functional client side data cache coherence distributed across database servers and clients. This system includes an application resident on a client operable to request access to data, and wherein the client is coupled to a local memory cache operable to store requested date. The client is coupled to a remote memory storage system, such as disk storage or network resources by a communication pathway. This remote memory storage system is operable to store data, process requests for specified data, retrieve the specified data from within the remote memory storage system, and transmit the requested data to the client with annotated version information. The data received by the client is verified as being coherent with any downstream linked information stored in the client'"'"'s local memory cache. Otherwise, updated coherent data is requested, received and verified prior to being used by the client and its resident applications.

Claims

1. A system for maintaining functional client side data cache coherence distributed across database servers and clients, comprising:

an application resident on a client operable to request access to at least one piece of specified data, and wherein said client is coupled to a local memory cache, wherein said local memory cache is operable to store said at least one piece of specified data; and

a remote memory storage system coupled to said client by a communication pathway, wherein said remote memory storage system is operable to store at least one piece of stored data, receive a request for at least one piece of specified data, retrieve said at least one piece of specified data from said at least one piece of stored data, and transmit said at least one piece of specified data to said client, and wherein said at least one piece of specified data provided to said client is annotated with version information.

2. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 1, wherein said at least one piece of specified data comprises a page, node, or linkage.

3. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 2, wherein a data file used by said application comprises said at least one piece of specified data.

4. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 1, wherein said application verifies that any piece of specified data is coherent with linked data stored in said local memory cache.

5. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 4, wherein said application uses said version information of both said received at least one piece of specified data and said linked data stored in said local memory cache.

6. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 1, wherein said version information comprises a version range and wherein any two pieces of data are coherent when said version range of said two pieces of data overlap.

7. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 6, wherein said version range comprises a file version for when a linkage to or from a node was updated and a file version for when said node was downloaded to a clients cache.

8. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 7, wherein said node comprises data, pages or links.

9. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 1, wherein any w rites to said data stored in either said local memory cache or said remote memory storage system are processed by said remote memory storage system prior to executing said write.

10. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 1, wherein said specified data transmitted from said remote memory storage system is transmitted as part of a data payload, wherein said payload comprises normal data, invalidation information and an invalidation header.

11. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 10, wherein said normal data comprises said specified data annotated with version information.

12. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 11, wherein said invalidation header is synchronous or asynchronous.

13. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 11, wherein invalidations having synchronous invalidation headers are processed first.

14. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 11, wherein if said invalidation header is asynchronous, said invalidation is placed in an invalidation queue to be processed.

15. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 14, wherein a user specifies a frequency for processing said invalidation queue.

16. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 1, wherein said remote memory storage system is a local disk accessed memory system.

17. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 1, wherein said remote memory storage system is a network accessed resource.

18. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 1, wherein said client and said remote memory storage system can switch to a client-server mode for improved efficiency when needed.

19. The system for maintaining functional client side data cache coherence distributed across database servers and clients of claim 1, wherein storing said at least one piece of stored data is tuned.

20. A method for maintaining functional client side data cache coherence distributed across database servers and clients, comprising:

requesting access to at least one piece of specified data from an application resident on a client, and wherein said client is coupled to a local memory cache;

coupling said client to a remote memory storage system, wherein said remote memory storage system is operable to;

store at least one piece of stored data;

receive a request for at least one piece of specified data from said client;

retrieve said at least one piece of specified data from said at least one piece of stored data; and

transmit said at least one piece of specified data to said client, and wherein said at least one piece of specified data provided to said client is annotated with version information;

verifying said at least one piece of specified data is coherent with any downstream linked information stored at said client in said local memory cache; and

storing said at least one piece of specified data in said local memory cache.

21. The method of claim 20, said data comprises a page, node, or linkage.

22. The method of claim 21, wherein a data file used by said application comprises said data.

23. The method of claim 20, wherein said application uses said version information of both said received at least one piece of specified data and said linked data stored in said local memory cache to verify coherence.

24. The method of claim 21, wherein said version information comprises a version range and wherein two pieces of data are coherent when said version range of said two pieces of data overlap.

25. The method of claim 24, wherein said version range comprises wherein said version range comprises a file version for when a linkage to or from a node was updated and a file version for when said node was downloaded to a clients cache.

26. The method of claim 20, wherein any writes to said data stored in either said local memory cache or said remote memory storage system are processed by said remote memory storage system prior to executing said write.

27. The method of claim 20, wherein data transmitted from said remote memory storage system comprises a data payload, wherein said payload comprises header information, invalidation meta data, and normal data.

28. The method of claim 27, wherein said normal data comprises said specified data annotated with version information.

29. The method of claim 27, wherein said invalidation meta data comprises a synchronous or asynchronous header.

30. The method of claim 28, wherein invalidations having synchronous invalidation headers are processed first.

31. The method of claim 29, wherein if said invalidation header is asynchronous, said invalidation is placed in an invalidation queue to be processed.

32. The method of claim 31, wherein a user specifies a frequency for processing said invalidation queue.

33. The method of claim 20, wherein said remote memory storage system is a local disk accessed memory system.

34. The method of claim 20, wherein said remote memory storage system is a network accessed resource.