Abstract:
Embodiments of the present invention address deficiencies of the art in respect to data synchronization and provide a method, system and computer program product for protocol optimization for client and server synchronization. In one embodiment a protocol optimization method for client and server synchronization can be provided. The method can include receiving server updates from a synchronization server, and applying each update to a client data store in parallel to requesting additional ones of the server updates from the synchronization server before completing the application to the client data store. In one aspect of the embodiment, receiving server updates from a synchronization server can include receiving server update subsets of a singular server update for a synchronization conversation from a synchronization server.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to the field of data synchronization and more particularly to the use of a synchronization framework to provide data synchronization services.  
         [0003]     2. Description of the Related Art  
         [0004]     Personal computers no longer are the most common vehicle through which users connect to data communications networks like the Internet. Now that computing can be viewed as being truly everywhere, computer scientists and information technologists have begun to rethink those services that can be provided to meet the needs of mobile computing users. In consequence, the study of pervasive computing has resulted in substantial innovation in the field of network connectivity. “Pervasive computing” has been defined as referring to any non-constrained computing device not physically tethered to a data communications network. Thus, pervasive computing devices refer not only to computers wirelessly linked to networks, but also to handheld computing devices, wearable systems, embedded computing systems and the like.  
         [0005]     Most pervasive devices, including notebook computers, handheld computers and even data enabled cellular telephones permit data synchronization with a different computing device, for example a desktop computer. Data synchronization refers to the harmonization of data between two data sources such that the data contained in each data source can be reconciled notwithstanding changes to the data applied in either or both of the data sources. Modern pervasive devices provide for a synchronization process through a direct cable link, a modem link, or a network link to a host computing device. Wireless pervasive devices further can accommodate synchronization over infrared or radio frequency links.  
         [0006]     To facilitate the synchronization of disparate devices hosting different applications, synchronization frameworks like the framework specified by “SyncML” have been proposed. Generally, a synchronization framework defines an interoperable protocol for data synchronization between heterogeneous data stores on pervasive devices and connected servers. Such synchronization frameworks further define the message exchange between client and server to accomplish synchronization. Yet, by design, synchronization frameworks do not specify the actual process required to accomplish synchronization.  
         [0007]     Contemporary protocol synchronization frameworks facilitate the harmonization of data in the data stores of a local and host device over a communications medium such as a wireless link. In the ordinary course of synchronization, a client device retrieves data updates since a last synchronization from the local data store and provides those updates to the host device. The host device applies the updates to the host data store and provides updates since the last synchronization from the host data store to the client device. To identify updated data, the host device relies upon local identifiers previously provided by the client device.  
         [0008]     The client, upon receipt of the host updates, iterates through each update applying the same to the local data store. Only once all updates have been applied locally, will the client device provide updated mapping information to the host device in order to facilitate subsequent synchronizations. As such, it will be recognized by the skilled artisan that the serial nature of client side updates and the heavy reliance upon providing a local identifier mapping can render contemporary synchronization protocols susceptible to failure conditions and slow responsiveness. Additionally, the skilled artisan will recognize that processing in the client device can be slow compared to processing in the server and the network link further can inhibit the speed of synchronization.  
         [0009]     Specifically, where the communications link becomes interrupted mid-synchronization, all progress will be lost. Moreover, in as much as the client device must await the completion of the update process in the local data store before forwarding the local identifier mapping to the host device, substantial delays can be incurred where the update process is slow due to the nature of an applicable pervasive device. Finally, contemporary synchronization protocols fail to account for the reality of traffic transfer with the bulk of the update traffic in a synchronization process stemming from the host device rather than the client device.  
       BRIEF SUMMARY OF THE INVENTION  
       [0010]     Embodiments of the present invention address deficiencies of the art in respect to data synchronization and provide a novel and non-obvious method, system and apparatus for a protocol optimization for client and server synchronization. In one embodiment an optimized synchronization protocol enabled data processing system can be provided. The system can include a synchronization client configured for communicative coupling to a synchronization server for a common application over a communications medium, a data store of data for the common application, and a data store agent coupled to each of the synchronization client and the data store.  
         [0011]     The agent can include program code enabled to process updates to the data store for the common application on behalf of the synchronization client in parallel with the synchronization client exchanging communications with the synchronization server as part of a synchronization conversation. For instance, the updates can be subsets of a single server update for the synchronization conversation. The agent further can include additional program code enabled to assign pre-allocated temporary local identifiers to local objects associated with the subsets and to provide the assigned pre-allocated temporary local identifiers to the synchronization server responsive to receiving the subsets from the synchronization server.  
         [0012]     In another embodiment of the invention, a protocol optimization method for client and server synchronization can be provided. The method can include receiving server updates from a synchronization server, and applying each update to a client data store in parallel to requesting additional ones of the server updates from the synchronization server before completing the application to the client data store. In one aspect of the embodiment, receiving server updates from a synchronization server can include receiving server update subsets of a singular server update for a synchronization conversation from a synchronization server.  
         [0013]     In another aspect of the embodiment, the method further can include pre-allocating temporary local identifiers for assignment to local objects associated with incoming ones of the server update subsets, providing a mapping of the pre-allocated temporary local identifiers corresponding to the local objects to the synchronization server, and providing an updated mapping to the synchronization server when all of the server update subsets of the singular server update have been received and applied to the client data store. As such, when an interruption in the synchronization conversation is detected, the synchronization conversation can be resumed at a point proximate to a last processed server update subset.  
         [0014]     Additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The aspects of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0015]     The accompanying drawings, which are incorporated in and constitute part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. The embodiments illustrated herein are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown, wherein:  
         [0016]      FIG. 1  is a schematic illustration of a data processing system enabled for protocol optimized data synchronization; and,  
         [0017]      FIG. 2  is an event diagram illustrating a process for protocol optimized data synchronization. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     Embodiments of the present invention provide a method, system and computer program product for protocol optimized data synchronization. In accordance with an embodiment of the present invention, server updates to a client during data synchronization for a common application can be stored in a client data store in parallel to the retrieval of server update blocks. Furthermore, a single server update to the client for a complete synchronization can be partitioned into multiple update exchanges of server update subsets between the client and the server. Finally, pre-allocated temporary local identifiers can be mapped to server side data objects during the course of data synchronization so that interruptions to the synchronization process can be resumed without requiring a restart of the synchronization process.  
         [0019]     By performing server updates to the client in parallel to the retrieval of server update blocks, the slow, serialized process characteristic of conventional data synchronization protocols can be eliminated in favor of faster, parallel processing. Additionally, by partitioning a single server update to the client for a complete synchronization into multiple update exchanges of server update subsets between the client and the server, both performance and failure recovery goals can be met more readily. Finally, by pre-allocating temporary local identifiers for mapping to server side data objects during the course of data synchronization, interruptions to the synchronization process can be resumed without requiring a restart of the synchronization process.  
         [0020]     In more particular illustration of an exemplary embodiment of the invention,  FIG. 1  is a schematic illustration of a data processing system enabled for protocol optimized data synchronization. The data processing system can include a host computing platform  130  coupled to one or more client computing platforms  110  over a computer communications medium  120 , for example a wire bound or wireless data communications medium. Both the host computing platform  130  and each client computing platform  110  can support the operation of a common application  190 A,  190 B enabled for data synchronization according to a synchronization protocol.  
         [0021]     To enable data synchronization for the common application  190 A,  190 B, a synchronization server  140  can be provided in the host computing platform  130 , and a synchronization client  180  can be provided in each client computing platform  1   10 . The synchronization client  180  and synchronization server  140  can be configured to negotiate and manage a data synchronization process for data in the common application  190 A,  190 B across the communications medium  120 . Generally, data utilized by the common application  190 A disposed in the client computing platform  110  can be stored in the data store  150 .  
         [0022]     Notably, a synchronization agent  170  can be disposed logically between the synchronization client  180  and the client data store  150  in that the synchronization agent  170  can manage updates to the client data store  150  on behalf of the client data store  150  without requiring the synchronization client  180  to directly communicate with the client data store  150 . The synchronization agent  170  can include program code enabled to parallel process updates to the client data store  150  on behalf of the synchronization client  180  allowing the synchronization client  180  to return to communicating with the synchronization server  140 . In this way, the synchronization client  180  need not wait for the successful completion of the update process to the data store  150  before resuming a synchronization conversation with the synchronization server  140 .  
         [0023]     Importantly, the program code of the synchronization agent  170  further can be enabled to process a single server update for the application  190 A,  190 B in multiple, partitioned sub-sets of the update. Furthermore, temporary local identifiers  160  for stored objects in the data store  150  can be provided for each of the partitioned sub- sets. In this regard, the program code can be enabled to pre-assign temporary local identifiers  160  to synchronized data in each of the sub-sets of the update. The temporary local identifiers  160  can be mapped to local objects in the host computing platform  130  without waiting for the update process in the data store  150  to complete for each sub-set of the update. Additionally, any interruption in the synchronization process can be cured by a simple resumption in the synchronization process beginning with the last processed sub-set of the update.  
         [0024]     In more particular illustration,  FIG. 2  is an event diagram illustrating a process for protocol optimized data synchronization. Beginning with path  205 , the synchronization client can forward a request to the data store agent for changes to the client data store. In path  210 , the data store agent can forward the changes to the synchronization client for synchronization with the synchronization server. In path  215 , the synchronization client can post the changes to the synchronization server and in path  220 , the synchronization server can reply to the synchronization client with a subset of a complete set of server updates for the synchronization conversation.  
         [0025]     In path  225 , the subset of server updates can be provided to the data store agent and the data store agent can respond in path  230  with a pre-allocated local mapping of temporary identifiers for the objects referenced in the subset of updates. Thereafter, the data store agent in path  235  can provide the subset of server updates to the client data store for storage. In path  245 , the data store can process the storage of the subset of server updates and, when finished, in path  250  the data store can provide local identifiers for the subset of server updates to the data store agent. Thereafter, the synchronization server in path  255  can provide a new subset of server updates to the synchronization client for processing according to paths  225  through  250 .  
         [0026]     Specifically, in path  260  the subset of server updates can be provided to the data store agent and the data store agent can respond in path  265  with a pre-allocated local mapping of temporary identifiers for the objects referenced in the subset of updates. Additionally, the data store agent can respond in path  265  with a local mapping of final identifiers for the previously stored objects. Thereafter, the data store agent in path  275  can provide the subset of server updates to the client data store for storage and the server in path  270  can apply both the temporary and final mappings as the case may be. In path  280 , the data store can process the storage of the subset of server updates and, when finished, in path  290  the data store can provide local identifiers for the subset of server updates to the data store agent.  
         [0027]     This process can continue until all subsets of the server updates have completed to form a complete server update for the synchronization conversation. At the completion of the last subset of the server updates, in path  295  an update done message can be forwarded to the synchronization client. In response to the receipt of the update done message, in path  300 , the synchronization client can post a local mapping of object identifiers to the synchronization server so that the synchronization server can have a true and correct mapping absent the temporary identifiers assigned previously. In path  305 , the synchronization server can acknowledge the mapping. Thereafter, anticipating a new synchronization conversation, in path  310  a new set of temporary local identifiers can be requested of the client data store and the client data store can respond in path  315  by providing a set of pre-allocated temporary local identifiers to the data store agent.  
         [0028]     Importantly, the process of updating the client data store can occur in a separate thread of execution from the thread of execution utilized by the synchronization client in conducting the synchronization conversation with the synchronization server. Consequently, the process of updating the data store can occur in parallel to the process of communicating with the synchronization server. Moreover, as the complete server update of the singular synchronization conversation can be partitioned into small subsets of server updates assigned to temporary local identifiers, a disruption in communications can be cured by resuming the synchronization conversation at the last set of stored temporary local identifier mappings.  
         [0029]     Embodiments of the invention can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment containing both hardware and software elements. In a preferred embodiment, the invention is implemented in software, which includes but is not limited to firmware, resident software, microcode, and the like. Furthermore, the invention can take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system.  
         [0030]     For the purposes of this description, a computer-usable or computer readable medium can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The medium can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk. Current examples of optical disks include compact disk-read only memory (CD-ROM), compact disk-read/write (CD-R/W) and DVD.  
         [0031]     A data processing system suitable for storing and/or executing program code will include at least one processor coupled directly or indirectly to memory elements through a system bus. The memory elements can include local memory employed during actual execution of the program code, bulk storage, and cache memories which provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution. Input/output or I/O devices (including but not limited to keyboards, displays, pointing devices, etc.) can be coupled to the system either directly or through intervening I/O controllers. Network adapters may also be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks. Modems, cable modem and Ethernet cards are just a few of the currently available types of network adapters.