Methods and systems for moving data using locks

• US 7,693,881 B2
• Filed: 09/04/2003
• Issued: 04/06/2010
• Est. Priority Date: 09/09/2002
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Fischer, Martin, Pferdekamper, Thorsten
• Primary Examiner(s): Alam; Hosain T
• Assistant Examiner(s): LIN, SHEW FEN
• Application Number:
  US10/526,749
• Publication Number:
  US 20060155704A1
• Time in Patent Office: 2,406 Days
• Field of Search: None
• US Class Current: 707/640
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms

Abstract

Methods, computer readable medium and systems are provided for moving data objects from a first storage location to a second storage location. One or more data objects may be selected having an identifier from a first storage location. The ID may be stored in a second lock object. Systems and methods consistent with the invention may determine whether the ID is stored successfully, and upon a successful storage, may store the ID in a first lock object. The data object is stored at a second storage location and the data object is deleted from the first storage location. After the ID has been stored in a first lock object, the ID is then deleted from the second lock object.

Claims

1. A method for moving data objects in a computer system from a first storage location to a second storage location, the method comprising:

selecting a data object from the first storage location;

determining whether an identifier (ID) of the data object is stored in a transactional lock object, the ID comprising one or more key fields of the data object;

when the ID is not stored in the transactional lock object, storing the ID in the transactional lock object, indicating that an action is being performed on the data object;

determining whether the ID is stored in a permanent lock object;

when the ID is not stored in the permanent lock object, storing the ID in the permanent lock object, indicating that the data object is subject to a moving process;

deleting the ID from the transactional lock object after storing the ID in the permanent lock object;

storing a copy of the data object at the second storage location;

determining whether the copy of the data object is successfully stored at the second storage location; and

when the copy of the data object is successfully stored at the second storage location;

assigning the copy of the data object stored at the second storage location to the ID in the permanent lock object;

deleting the data object from the first storage location; and

deleting the ID from the permanent lock object after deleting the data object from the first storage location.

2. The method of claim 1, wherein the data object comprises one or more fields of one or more tables.

3. The method of claim 1, wherein the data object is stored in a file and wherein an assignment of the ID to the file or to a name of the file is stored in the permanent lock object.

4. The method of claim 1, wherein the permanent lock object is stored on a nonvolatile storage means.

5. The method of claim 1, wherein the ID is stored in the transactional lock object after selecting the data object from the first storage location.

6. The method of claim 1, wherein the ID is stored in the transactional lock object before storing the copy of the data object at the second storage location.

7. The method of claim 1, wherein storing the ID in the permanent lock object further comprises:

storing IDs of other data objects in the permanent lock object before storing the copy of the data object at the second storage location.

8. The method of claim 1, further comprising:

when the ID is stored in the permanent lock object, skipping storing the copy of the data object at the second storage location.

9. The method of claim 1, further comprising:

determining whether another copy of the data object is stored in the second storage location; and

when another copy of the data object is stored in the second storage location, skipping storing the copy of the data object at the second storage location.

10. The method of claim 9, wherein determining whether another copy of the data object is stored in the second storage location comprises determining whether the ID is stored in the permanent lock object.

11. The method of claim 1, further comprising:

when storing the copy of the data object in the second storage location was not successful, skipping deleting the data object from the first storage location and skipping deleting the ID from the permanent lock object.

12. The method of claim 1 for use in an enterprise resource planning software.

13. The method of claim 1, wherein deleting the ID from the transactional lock object indicates that the action is not being performed on the data object.

14. A computer system for processing data, the computer system comprising:

memory means for storing program instructions;

input means for entering the data;

storage means for storing the data;

a processor responsive to the program instructions, wherein the program instructions comprise program code means for performing a method for moving data objects in the computer system from a first storage location to a second storage location, the method comprising;

selecting a data object from the first storage location;

determining whether an identifier (ID) of the data object is stored in a transactional lock object, the ID comprising one or more key fields of the data object;

when the ID is not stored in the transactional lock object, storing the ID in the transactional lock object, indicating that an action is being performed on the data object;

determining whether the ID is stored in a permanent lock object;

when the ID is not stored in the permanent lock object, storing the ID in the permanent lock object, indicating that the data object is subject to a moving process;

deleting the ID from the transactional lock object after storing the ID in the permanent lock object;

storing a copy of the data object at the second storage location;

determining whether the copy of the data object is successfully stored at the second storage location; and

when the copy of the data object is successfully stored at the second storage location;

assigning the copy of the data object stored at the second storage location to the ID in the permanent lock object;

deleting the data object from the first storage location; and

deleting the ID from the permanent lock object after deleting the data object from the first storage location.

15. The computer system of claim 14, wherein deleting the ID from the transactional lock object indicates that the action is not being performed on the data object.

16. A computer readable storage medium comprising instructions for performing a method for moving data objects in a computer system from a first storage location to a second storage location, the method comprising:

selecting a data object from the first storage location;

determining whether an identifier (ID) of the data object is stored in a transactional lock object, the ID comprising one or more key fields of the data object;

when the ID is not stored in the transactional lock object, storing the ID in the transactional lock object, indicating that an action is being performed on the data object;

determining whether the ID is stored in a permanent lock object;

when the ID is not stored in the permanent lock object, storing the ID in the permanent lock object, indicating that the data object is subject to a moving process;

deleting the ID from the transactional lock object after storing the ID in the permanent lock object;

storing a copy of the data object at the second storage location;

determining whether the copy of the data object is successfully stored at the second storage location; and

when the copy of the data object is successfully stored at the second storage location;

assigning the copy of the data object stored at the second storage location to the ID in the permanent lock object;

deleting the data object from the first storage location; and

deleting the ID from the permanent lock object after deleting the data object from the first storage location.

17. The computer readable storage medium of claim 16, wherein the data object comprises one or more fields of one or more tables.

18. The computer readable storage medium of claim 16, wherein the data object is stored in a file and wherein an assignment of the ID to the file or to a name of the file is stored in the permanent lock object.

19. The computer readable storage medium of claim 16, wherein the permanent lock object is stored on a nonvolatile storage means.

20. The computer readable storage medium of claim 16, wherein the ID is stored in the transactional lock object after selecting the data object from the first storage location.

21. The computer readable storage medium of claim 16, wherein the ID is stored in the transactional lock object before storing the copy of the data object at the second storage location.

22. The computer readable storage medium of claim 16, wherein storing the ID in the permanent lock object further comprises:

storing IDs of other data objects in the permanent lock object before storing the copy of the data object at the second storage location.

23. The computer readable storage medium of claim 16, wherein the method further comprises:

when the ID is stored in the permanent lock object, skipping storing the copy of the data object at the second storage location.

24. The computer readable storage medium of claim 16, wherein the method further comprises:

determining whether another copy of the data object is stored in the second storage location; and

when another copy of the data object is stored in the second storage location, skipping storing the copy of the data object at the second storage location.

25. The computer readable storage medium of claim 24, wherein determining whether another copy of the data object is stored in the second storage location comprises determining whether the ID is stored in the permanent lock object.

26. The computer readable storage medium of claim 16, wherein the method further comprises:

when storing the copy of the data object in the second storage location was not successful, skipping deleting the data object from the first storage location and skipping deleting the ID from the permanent lock object.

27. The computer readable storage medium of claim 16, wherein the computer readable medium is provided as part of a computer program product.

28. The computer readable storage medium of claim 16, wherein deleting the ID from the transactional lock object indicates that the action is not being performed on the data object.

29. A computerized system for moving data objects from a first storage location to a second storage location, the computerized system comprising:

a processor executing program instructions;

means for selecting a data object from the first storage location;

means for determining whether an identifier (ID) of the data object is stored in a transactional lock object, the ID comprising one or more key fields of the data object;

means for storing the ID in the transactional lock object, indicating that an action is being performed on the data object, when the ID is not stored in the transactional lock object;

means for determining whether the ID is stored in a permanent lock object;

means for storing the ID in the permanent lock object, indicating that the data object is subject to a moving process, when the ID is not stored in the permanent lock object;

means for deleting the ID from the transactional lock object after storing the ID in the permanent lock object;

means for storing a copy of the data object at the second storage location;

means for determining whether the copy of the data object is successfully stored at the second storage location; and

means for, when the copy of the data object is successfully stored at the second storage location;

assigning the copy of the data object stored at the second storage location to the ID in the permanent lock object;

deleting the data object from the first storage location; and

deleting the ID from the permanent lock object after deleting the data object from the first storage location.

30. The computer system of claim 29, wherein the data object comprises one or more fields of one or more tables.

31. The computer system of claim 29, wherein the data object is stored in a file and wherein an assignment of the ID to the file or to a name of the file is stored in the permanent lock object.

32. The computer system of claim 29, wherein the permanent lock object is stored on a nonvolatile storage means.

33. The computer system of claim 29, wherein the ID is stored in the transactional lock object after selecting the data object from the first storage location.

34. The computer system of claim 29, wherein the ID is stored in the transactional lock object before storing the copy of the data object at the second storage location.

35. The computer system of claim 29, wherein the means for storing the ID in the permanent lock object further comprises:

means for storing IDs of other data objects in the permanent lock object before storing the copy of the data object at the second storage location.

36. The computer system of claim 29, further comprising:

means for skipping storing the copy of the data object at the second storage location when the ID is stored in the permanent lock object.

37. The computer system of claim 29, further comprising:

means for determining whether another copy of the data object is stored in the second storage location; and

means for skipping storing the copy of the data object at the second storage location when another copy of the data object is stored in the second storage location.

38. The computer system of claim 37, wherein the means for determining whether another copy of the data object is stored in the second storage location comprises means for determining whether the ID is stored in the permanent lock object.

39. The computer system of claim 29, further comprising:

means for skipping deleting the data object from the first storage location and skipping deleting the ID from the permanent lock object when storing the copy of the data object in the second storage location was not successful.

40. The computerized system of claim 29, wherein deleting the ID from the transactional lock object indicates that the action is not being performed on the data object.