DETERMINING PRIORITY BETWEEN DATA ITEMS

• US 20080104136A1
• Filed: 12/28/2007
• Published: 05/01/2008
• Est. Priority Date: 05/02/2002
• Status: Abandoned Application

• Current Assignee: Palmsource Incorporated (Access Company Limited)
• Original Assignee: Palmsource Incorporated (Access Company Limited)
• Inventors: Pivowar, Alvin, Mills, William
• Application Number:
  US11/966,950
• Publication Number:
  US 20080104136A1
• Time in Patent Office: Days
• US Class Current: 707/201
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

One embodiment of the present invention enables nodes or endpoints involved with synchronization of data items to determine which version of a data item (if any) has priority over another version of that same data item. Within the present embodiment, when a data item Is modified by a node, it is presumed that the modified data item takes priority aver the previous version of that data item. Therefore, the “descendant” data item (modified) takes precedence over its “ancestor” data item (previous version). By including this type of “pedigree” information with data items involved with synchronization between different nodes or endpoints, the present embodiment enables the endpoints to determine which version of a data item (if any) has priority over another version of that same data item.

Claims

1-27. -27. (canceled)

28. A node comprising:

memory adapted to store one or more data records, the data records being associated with pedigree information indicative of any prior modifications to the data records;

a user interface unit for receiving user input with which to enter into a data record residing in the node; and

identification logic adapted to identify a data record as having been modified via user input at the node using a pedigree identifier;

wherein the pedigree identifier establishes priority of the data as modified by the user input over previous versions of the data record.

29. The node of claim 28, wherein the pedigree identifier includes at least a node identity designation and a value of a synchronization counter at the node.

30. The node of claim 29, wherein if the data record includes pedigree identifiers previously associated with the data record at other nodes and the data record has not been previously received at the node, the identification logic is adapted to append the pedigree identifier of the node including the node identifier and synchronization counter value to the previously-placed identifiers.

31. The node of claim 29, wherein if the data record includes pedigree identifiers previously associated with the data record at other nodes and the data record has been previously received at the node, the identification logic is adapted to update the pedigree identifier of the node with a latest synchronization counter value.

32. The node of claim 29, further comprising:

comparison logic adapted to establish a priority of a first and second versions of a data record by comparing the pedigree identifiers associates with the first and second versions of the data record.

33. The node of claim 29, further comprising:

logic for determining whether a data record has been deleted within the node.

34. The node of claim 33, further comprising:

logic for preserving an identify of the data record, a pedigree identifier, and a deleted status identifier of a deleted data record.

35. The node of claim 34, wherein the data record, pedigree identifier, and deleted status identifier of the deleted data record are preserved as a recognizable stub.

36. The node of claim 35, further comprising:

counting logic for determining the number of stubs reside on the node.

37. The node of claim 36, further comprising:

determining logic for determining whether the number of stubs residing on the node is greater than a first threshold value; and

logic for removing stubs having pedigree identifiers with synchronization counter values below a second threshold value.

38. The node of claim 29, wherein the one or more records are stored in one or more databases.

39. The node of claim 29, wherein each database has its own synchronization counter.

40. A multimode-system in which up-to-date data records are maintained comprising:

a first node having a processor, means for inter-node communication, and memory for storing a first version of a data record associated with a first pedigree identifier;

a second node having a processor, means for inter-node communication, and memory for storing a second version of the same data record associated with a second pedigree identifier;

wherein during a synchronization process in which the first node and second node exchange data records, at least one of the first node and second node is adapted to;

compare the first and second pedigree identifiers of the first and second data records;

determine which of the first and second versions of the data record have priority based on the comparison;

if the first version of the data record is determined to have lower priority, the first node replaces the first version of the data record and the first pedigree identifier with the second version of the data record; and

if the second version of the data record is determined to have lower priority, the second node replaces the second version of the data record.

41. The multi-node system of claim 40, wherein the first pedigree identifier includes at least an identifier of the first node and a value of a synchronization counter at the first node, and the second pedigree identifier includes at least an designation of the second node and a value of a synchronization counter at the second node.

42. The multi-mode system of claim 41, wherein:

if the second version is to replace the first version of the data record at the first node, the first node is adapted to determine if the first pedigree identifier already includes a second node designation;

if the first pedigree identifier does not include a second node designation, the first node is adapted append to the first pedigree identifier the second node designation with the synchronization counter value of the second pedigree identifier; and

if the first pedigree identifier does include a second node designation, the first node updates the synchronized counter value associated with the second node designation to the synchronization counter value in the second pedigree identifier.

43. The multi-mode system of claim 41, wherein:

if the first version is to replace the second version of the data record at the second node, the second node is adapted to determine if the second pedigree identifier already includes a node designation of the first node;

if the second pedigree identifier does not include a first node designation, the second node is adapted append to the second pedigree identifier the first node designation with the synchronization counter value of the second pedigree identifier; and

if the second pedigree identifier does include a second node designation, the first node updates the synchronized counter value associated with the second node designation to the synchronization counter value in the second pedigree identifier.

44. The multi-mode system of claim 41, wherein the first node stores the first version of the data record in a first database, and the second node stores the second version of the data record in a second database.

45. The multi-node system of claim 41, wherein the first and second databases each have their own synchronization counters.

46. The multi-mode system of claim 41, wherein, during a synchronization process, the first node is adapted to determine whether data records have been deleted from the second node, and the second node is adapted to determine whether data records have been deleted from the first node.

47. The multi-mode system of claim 46, wherein the first node stores a data record identifier, a pedigree identifier, and a deleted status identifier of each data record deleted on the first node, and the second node stores a data record identifier, a pedigree identifier, and a deleted status identifier of each data record deleted on the second node.

48. The multi-mode system of claim 47, wherein the first and second nodes preserve the data record, pedigree identifier, and deleted status identifiers of the deleted data record are preserved as recognizable stubs.

49. The multi-mode system of claim 47, wherein the first and second nodes are each adapted to determine whether a number of stubs residing on their respective nodes exceed a threshold value, and to remove a number of stubs if it is so determined.

50. The multi-mode system of claim 47, wherein the first and second nodes are each adapted to remove stubs having pedigree identifiers with synchronization counter values below another threshold value.