Method and apparatus for efficient management of XML documents

• US 6,941,510 B1
• Filed: 06/06/2000
• Issued: 09/06/2005
• Est. Priority Date: 06/06/2000
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Groove Networks, Inc. (Microsoft Corporation)
• Inventors: Richardson, Ransom L., Ozzie, Raymond E., Fischer, Edward J., Moore, Kenneth G.
• Primary Examiner(s): Feild, Joseph
• Assistant Examiner(s): Nguyen, MaiKhanh
• Application Number:
  US09/588,195
• Time in Patent Office: 1,918 Days
• Field of Search: 715/513, 715/530, 715/501.1, 709/201, 709/206, 709/215, 709/400, 711/147, 711/202, 707/8
• US Class Current: 715/234
• CPC Class Codes: G06F 16/986 Document structures and storage, e.g. HTML extensions
• CPC Class Codes: G06F 40/123 Storage facilities
• CPC Class Codes: G06F 40/143 Markup, e.g. Standard Generalized Markup Language [SGML] or Document Type Definition [DTD]
• CPC Class Codes: G06F 40/221 Parsing markup language streams streaming G06F40/149

Abstract

An in-memory storage manager represents XML-compliant documents as a collection of objects in memory. The storage manager allows real-time access to the objects by separate processes operating in different contexts. The data in the objects is stored in memory local to each process and the local memories are synchronized by means of a distributed memory system that stores the data in the same data region, but maps the data region to the address space of each process. Data corruption in the data region is prevented by a locking mechanism that prevents the processes from simultaneously modifying same data.

Claims

1. Apparatus for representing and managing an XML-compliant document in a memory, the XML-compliant document being updated concurrently by a first process having a first address space in the memory and second process having a second address space in the memory, the apparatus comprising:

a first storage manager controlled by the first process that constructs, from class code in the first address space, at least one document object including first data representing a part of the XML-compliant document and stored in a region mapped into the first address space;

a second storage manager controlled by the second process that constructs, from class code in the second address space, at least one document object including second data representing a part of the XML-compliant document and stored in the same region as the first data, but mapped into the second address space;

a synchronization mechanism that locks the region data when the first process is changing the region data in the first address space.

2. Apparatus as recited in claim 1 wherein the second process comprises a mechanism for requesting a copy of the region data from the first address space if the second address space does not have the most recent copy of the region data.

3. Apparatus as recited in claim 1 wherein the second process comprises methods for requesting that the synchronization manager lock the region data when the second process is changing the region data in the second address space.

4. Apparatus as recited in claim 1 wherein the first process can perform read and write operations on the region and wherein the apparatus further comprises a mechanism for grouping a plurality of the read and write operations into a transaction.

5. Apparatus as recited in claim 4 wherein the first process comprises methods for requesting that the synchronization manager lock the region data during the processing of all read and write operations in a transaction.

6. Apparatus as recited in claim 5 further comprising a logging system that periodically writes recovery log entries to a persistent database during the processing of all read and write operations in a transaction.

7. Apparatus as recited in claim 1 wherein the first process comprises a storage mechanism for storing a copy of the region data in a non-volatile store.

8. Apparatus as recited in claim 7 wherein the non-volatile store comprises an object store.

9. Apparatus as recited in claim 7 wherein the non-volatile store comprises a file system.

10. Apparatus as recited in claim 1 wherein the synchronization mechanism comprises a distributed memory system.

11. Apparatus as recited in claim 1 wherein both the first and second address spaces contain equivalent program code for manipulating the first and second document objects.

12. Apparatus as recited in claim 1 wherein the first and second storage manager each construct a cross-process synchronization object that is used to synchronize the first and second processes.

13. A method for representing and managing an XML-compliant document in a memory, the XML-compliant document being updated concurrently by a first process having a first address space in the memory and second process having a second address space in the memory, the method comprising:

(a) using a first storage manager controlled by the first process to construct, from class code in the first address space, at least one document object including first data representing a part of the XML-compliant document and stored in a region mapped into the first address space;

(b) using a second storage manager controlled by the second Process to construct, from class code in the second address space, at least one document object including second data representing a part of the XML-compliant document and stored in the same region as the first data, but mapped into the second address space; and

(c) locking the region data when the first process is changing the region data in the first address space.

14. A method as recited in claim 13 further comprising requesting a copy of the region data from the first address space if the second address space does not have the most recent copy of the region data.

15. A method as recited in claim 13 wherein step (c) comprises locking the region data when the second process is changing the region data in the second address space.

16. Apparatus as recited in claim 13 wherein the first process can perform read and write operations on the region and wherein the method further comprises (d) grouping a plurality of the read and write operations into a transaction.

17. A method as recited in claim 16 wherein step (c) comprises locking the region data during the processing of all read and write operations in a transaction.

18. A method as recited in claim 17 wherein step (c) further comprises periodically writing recovery log entries to a persistent database during the processing of all read and write operations in a transaction.

19. A method as recited in claim 13 further comprising (e) under the control of the first process, storing a copy of the region data in a non-volatile store.

20. A method as recited in claim 19 wherein the non-volatile store comprises an object store.

21. A method as recited in claim 19 wherein the non-volatile store comprises a file system.

22. A method as recited in claim 13 wherein step (c) is performed by a distributed memory system.

23. A method as recited in claim 13 further comprising (f) manipulating the first and second document objects with equivalent program code in both the first and second address spaces.

24. A method as recited in claim 13 further comprising (g) constructing a cross-process synchronization object that is used to synchronize the first and second processes.

25. A computer program product for representing and managing an XML-compliant document in a memory, the XML-compliant document being updated concurrently by a first process having a first address space in the memory and second process having a second address space in the memory, the computer program product comprising a computer usable medium having computer readable program code thereon, including:

program code for using a first storage manager controlled by the first process to construct, from class code in the first address space, at least one document object including first data representing a part of the XML-compliant document stored in the first address space and stored in a region mapped into the first address space;

program code for using a second storage manager controlled by the second process to construct, from class code in the second address space which class code is identical to the class code in the first address space, at least one document object including second data representing a part of the XML-compliant document stored in the second address space and stored in the same region as the first data, but mapped into the second address space; and

program code for locking the region data when the first process is changing the region data in the first address space.