Synchronizing logical views independent of physical storage representations

• US 7,216,133 B2
• Filed: 07/29/2003
• Issued: 05/08/2007
• Est. Priority Date: 07/29/2003
• Status: Active Grant

• Current Assignee: ServiceNow Incorporated
• Original Assignee: Microsoft Corporation
• Inventors: Novik, Lev, Wu, Yunxin, Zhou, Shaoyu, Hudis, Irena, Shah, Ashish B.
• Primary Examiner(s): Vo; Tim
• Assistant Examiner(s): GORTAYO, DANGELINO N
• Application Number:
  US10/629,254
• Publication Number:
  US 20050027747A1
• Time in Patent Office: 1,379 Days
• Field of Search: 707/101, 707/102, 707/201, 707/200, 709/248
• US Class Current: 707/620
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06Q 10/10 Office automation; Time management
• CPC Class Codes: Y10S 707/959 Network
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

Systems, methods, and computer program products for synchronizing items at replicas within a topology is disclosed. Items are stored in physical tables at the replicas. The physical table layouts at each replica can differ but are mapped to a common logical view. When a replica receives an indication that synchronization should be performed, the replica determines if changes have been made at the replica that should be mapped to the logical views. Replicas can facilitate this by comparing local change enumerations for changes made in physical tables to synchronization local change enumerations for changes in the logical views. Any changes that need to be synchronized are sent through the logical views to other replicas in the topology.

Claims

1. In a computer network comprised of a plurality of different types of platforms for storing replicas of the same data, and wherein the limitations or features of a particular platform may require the data of a replica to be stored in a different physical arrangement at the data store layer of the particular platform, and wherein when synchronizing the replicas the data for each replica must be mapped from the different physical arrangement at each platform into a logical view table of a synchronization layer of the particular platform that has a similar layout to the logical view table at each of the other different types of platforms, a method for mapping of the physical layout of items in a data store layer of a platform to a logical view in a synchronization layer of the platform, the method comprising:

an act of compiling at the computer system of a particular platform a logical schema into a catalog that can be used to define a logical view that has a similar layout to the logical view for each platform, and that includes a logical grouping of data items by defining the data items in terms of,

a change unit that defines the granularity of a group of data items in the sense that if any part of the group of data items is modified, the entire group of data items will be synchronized when synchronizing other replicas; and

a consistency unit, defining the minimum group of data items that must be reported during synchronization if any item of the group is changed;

an act of utilizing the catalog to map items from a physical layout to the logical view that has a similar layout to the logical view at different platforms of one or more other computer systems; and

an act of storing a synchronization tracker in the logical view table at the synchronization level for each platform, the synchronization tracker maintaining;

a version change enumeration corresponding to a synchronized version of a data item in the logical view of the computer system; and

a source identifier identifying a particular replica upon which the synchronized version of the data item is based.

2. The method as defined in claim 1, wherein the synchronization layer of the computer system includes a logical schema that is compiled into one or more catalogs, the one or more catalogs being in extensible mark-up language (XML).

3. The method as defined in claim 1 wherein the physical arrangement at the data store layer for each computer system is defined by one or more physical tables, and wherein the physical arrangement defined by the physical tables of at least one of the computer systems is different from the physical arrangement defined by the physical tables of the other computer systems.

4. The method as defined in claim 3, wherein the data store layer of each platform of each computer system where a replica is stored includes a user interface that includes procedures or functions code, the procedures or functions code being adapted to arrange the data for the replica in the physical tables of the data store layer.

5. The method as defined in claim 3, further comprising:

an act of storing a local change tracker in the one or more physical tables at the data store layer of each platform, the local change tracker maintaining local change enumerations for items stored in the data store layer of a platform;

wherein by comparing the local change tracker with the synchronization tracker, the computer system of each platform can determine if an item stored in the data store layer of the computer system should be sent and thus mapped to the logical view in the synchronization layer of the computer system.

6. The method of claim 5, wherein if the local change enumeration and the version change enumeration comprise different values, then the item stored in the data store layer of the computer system should be mapped to the logical view.

7. The method of claim 5, wherein if the local change enumeration and the version change enumeration comprise the same value, then the item stored in the data store layer of the computer system does not need to be mapped to the logical view.

8. The method of claim 5, wherein

a change in an item of data for a replica stored at a particular platform caused by a different version of the replica created by a computer system of another platform is identified by the source identifier corresponding to the computer system of the other platform, and

wherein a change in an item of data for a replica stored at a particular platform caused by a change created in the one or more physical tables of the data store of the particular platform is identified by a change enumeration corresponding to a chronological order that the change was made.

10. The method as defined in claims 1 or 9, wherein the platform at each computer system wherein a replica is stored includes in the synchronization layer of the computer system a logical schema that is compiled into a catalog that can be used to define a logical view that has a layout which is similar for each platform.

11. The method as defined in claims 1 or 9, wherein the physical arrangement at the data store layer of the platform for each computer system at which a replica is stored is defined by one or more physical tables for storing the data of the replica.

12. The method as defined in claims 1 or 9, wherein

the data store layer of the platform for each computer system at which a replica is stored includes one or more folders in which items grouped in a common folder can be synchronized, thereby defining the scope of synchronization between synchronization layers of different platforms, and

wherein the items grouped in a common folder that can be synchronized are less than all of the items stored for a replica.

9. In a computer network comprised of a plurality of different types of platforms for storing replicas of the same data, and wherein the limitations or features of a particular platform may require the data of a replica to be stored in a different physical arrangement at the data store layer of the particular platform, and wherein when synchronizing the replicas the data for each replica must be mapped from the different physical arrangement at each platform into a logical view table of a synchronization layer of the particular platform that has a similar layout to the logical view table at each of the other different types of platforms, a computer program product for implementing within the computer network a method for mapping of the physical layout of items in a data store layer of a platform to a logical view in a synchronization layer of the platform, the computer program product comprising a computer readable-medium having stored thereon computer-executable instructions for implementing the method, and wherein the method is comprised of:

an act of compiling at the computer system of the platform a logical schema into a catalog that can be used to define a logical view that has a similar layout to the logical view for each platform, and that includes a logical grouping of data items by defining the data items in terms of,

a change unit that defines the granularity of a group of data items in the sense that if any part of the group of data items is modified, the entire group of data items will be synchronized when synchronizing other replicas; and

a consistency unit, defining the minimum group of data items that must be reported during synchronization if any item of the group is changed;

an act of utilizing the catalog to map items from a physical layout to the logical view that has a similar layout to the logical view at different platforms of one or more other computer system; and

an act of storing a synchronization tracker in the logical view table at the synchronization level for each platform, the synchronization tracker maintaining;

a version change enumeration corresponding to a synchronized version of a data item in the logical view of the computer system; and

a source identifier identifying a particular replica upon which the synchronized version of the data item is based.