System and method for a caching mechanism for a central synchronization server

• US 20040153576A1
• Filed: 04/01/2004
• Published: 08/05/2004
• Est. Priority Date: 06/30/2001
• Status: Active Grant

• Current Assignee: King.com, Ltd (Microsoft Corporation)
• Original Assignee: International Business Machines Corporation
• Inventors: Purayakastha, Apratim, Hepper, Stefan, Stober, Thomas, Hansmann, Uwe, Heintzman, Douglas
• Granted Patent: US 7,539,778 B2
• Time in Patent Office: Days
• US Class Current: 709/248
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching

Abstract

The present invention discloses a new synchronization architecture for synchronization of data between different clients by using a central synchronization server linked to a Back End data store which additionally provides a cache for permanently buffering incoming updates into a permanent store by assigning an unique cache identifier (ID). Write conflicts between the synchronization server writing new entries to the cache and updates replicated from backend to cache are solved using a blocking mechanism based on the cache IDs, so that the backend updates are blocked as long as incoming updates from the clients having the same cache ID are not completely written into the cache during a synchronization session. The present invention is preferably suited for a synchronization architecture having a high number of clients connected with the central synchronization server as blocking of the Back End data store, and the connection and the transport to the Back End data store are minimized.

Claims

1. System for synchronization of data between different clients (2,4) by using a central synchronization server (6) having a connection to said clients (2,4) and a connection to a Back End data store (16), wherein said clients having a program for creation of data to be synchronized, and a synchronization engine for performing synchronization with said central synchronization server, wherein said Back End data store (16) having a data connection with an outside application (15) allowing updates of said data in said Back End data store (16), wherein said system is characterized by the further components:

a cache (24) for permanently buffering of updates of said Back End data store (16) and said clients (2,4), and

a caching mechanism component (18,20,23) for controlling and executing buffering updates into said cache (24) and replicating buffered updates to said respective clients and said Back End data store (16).

2. System according to claim 1, wherein said caching mechanism having cache management component (23) which provides the functionality to buffers updates of said clients (2,4) in said cache (24) by assigning an unique cache identifier (ID) and replicates updates from said cache (24) to said clients (2,4) and a backend monitor (18) which blocks buffering of updates from said Back End data store into said cache as long as updates from said clients having the same cache ID are not completely written into the cache (24) during a synchronization session.

3. System according to claim 1, wherein said cache mechanism having a persistent store (22) which provides the functionality to buffers updates of said clients or said back End data (16) store into said cache (24) only when the time stamp is newer than the time stamp of an update buffered or being buffered in said cache (24) having the same cache ID.

4. System according to claim 3, wherein said persistent store (22) provides the further functionality to map cache IDs to Backend.IDs.

5. System according to claim 2, wherein said caching mechanism having a cache monitor (20) which replicates updates from said cache (24) to the Back End data store (16) in a batch or a continuous trickle mode.

6. Systems according to claim 2, wherein said caching mechanism having a Back End Monitor (18) which replicates updates between said cache (24) and the Back End data store (16) in a batch or a continuous trickle mode.

7. Systems according to claim 1, wherein said cache (24) and said Back End data store (16) are databases.

8. System according to claim 1, wherein said clients (2,4) are mobile clients.

9. System according to claim 1, wherein the synchronization protocol is SyncML.

10. Method for synchronization of updates between clients by using system according to claim 1-9, comprising the steps of:

receiving an update from said client via said client'"'"'s synchronization engine containing version No., LUID and update data (2),

mapping version number of said update to an assigned synchronization time stamp by using mapping table (8),

mapping LUID of said update to assigned cache ID by using a mapping table (10),

buffering update data including time stamp and cache ID into said cache only when said time stamp of said update is newer than the time stamp of an update in said cache having the same cache ID (20),

mapping cache ID of said update to assigned backend (6) ID by using mapping table,

translating cache data format of said update into of said backend data store data format (22),

initiating update in said Back End data store containing update data, time stamp, and backendID (24).

11. Method for synchronization of updates between clients by using a system according to claim 1-9, comprising the steps of:

receiving an update from said client via said client'"'"'s synchronization engine containing version number, LUID and update data,

mapping version number of said update to an assigned synchronization time stamp by using mapping table,

mapping LUID of said update to assigned cache ID by using a mapping table,

buffering update data including time stamp and cache ID into said cache only when said time stamp of said update is newer than the time stamp of an update in said cache having the same cache ID,

generating a new backend ID if mapping cache ID to backend ID is not successful,

translating cache data format of said update into data format of said Back End data store,

initiating a new entry of said update in the Back End data store containing new entry data, time stamp, and backend ID, and

inserting new backend ID into the mapping table.

12. Method according to claim 10 or 11, wherein synchronization protocol used between said clients and said central synchronization server is SyncML and said updates received by said central synchronization server are presented as XML documents.

13. Method for replication an update from said Back End data store to said cache using a system according to claim 1-9, comprising the steps of:

receiving an update from said Back End data store by said central synchronization server containing update data, time stamp, and backend ID,

translating backend data format of said backend update into cache data format,

mapping backend ID to cache ID by using a mapping table, and

buffering of said update from said Back End data store into said cache only when the time stamp is newer than the time stamp of an update buffered in said cache having the same cache ID.

14. Method according to claim 13, wherein buffering of updates from said Back End data store into said cache are blocked as long as updates from said clients having the same cache IDs are not completely written into said cache during a synchronization session.

15. Method according to claim 13, comprising the further step:

generating a new cache ID when mapping backend ID to cache ID is not successful, and

inserting said new cache ID into the mapping table.

16. Computer program product stored in the internal memory of a digital computer, containing parts of software code to execute the method in accordance with claims 10 to 15 if the product is run on the computer.