Patent ID: 6219675
Filing Date: 2001-04-17
Classification: G06F,Y10S

Abstract:
A method in a data processing system for synchronizing database objects contained in a centralized database management system on a server computer with copies of the database objects stored in client computers, the synchronizing performed by a synchronization agent that is detached from the centralized database management system, the method performed by the synchronization agent comprising the steps of:receiving a request from one of the client computers requesting a selected one of the database objects;sending the request to the centralized database management system such that the centralized database management system grants a readlock on the selected database object;sending a copy of the selected database object to the client computer;storing an indication of the client computer into a directory structure, the indication indicating that the client computer has allocated the selected object;receiving a request from the client computer requesting a writelock for the selected database object;sending the writelock request to the centralized database management system such that the centralized database management system grants the writelock;accessing the directory structure to determine allocating clients that have allocated the selected object;sending to the allocating clients a callback message requesting a response when the allocating clients have completed use of the selected object, the callback message indicating that the selected object will become updated;receiving a request to modify the selected object from the client computer;waiting until receiving a response to each of the callback messages to ensure that the allocating clients have completed use of the selected object; andmodifying the selected object after receiving the response to each of the callback messages.