Distributed synchronization of databases

• US 6,223,187 B1
• Filed: 11/30/1999
• Issued: 04/24/2001
• Est. Priority Date: 09/11/1997
• Status: Expired due to Term

• Current Assignee: Intellisync Corporation (Nokia Corporation)
• Original Assignee: Puma Technology Inc.
• Inventors: Daley, Robert C., Boothby, David J.
• Primary Examiner(s): HOMERE, JEAN RAYMOND
• Application Number:
  US09/449,644
• Time in Patent Office: 511 Days
• Field of Search: 707/3, 707/4, 707/10, 707/201, 707/202, 707/203, 709/203, 709/219, 709/217, 709/248, 709/201
• US Class Current: 1/1
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A computer implemented method is provided for synchronizing a first database located on a first computer and a second database located on a second computer. At the first computer, it is determined whether a record of the first database has been changed or added since a previous synchronization, using a first history file located on the first computer comprising records representative of records of the first database at the completion of the previous synchronization. If the record of the first database has not been changed or added since the previous synchronization, the first computer sends the second computer information which the second computer uses to identify the record of the first database to be unchanged.

Claims

1. A computer implemented method of identifying a record of a first database stored on a first computer to a second computer storing a second database, as part of a process of synchronizing the first and second databases, comprising:

reading a first record of the first database;

assigning a code to the first record of the first database, the code being based on at least a portion of the content of the first record of the first database, the code being insufficient to reconstruct the record but sufficient to identify the record;

transmitting the code to the second computer to identify the first record to the second computer; and

using the code in the synchronization process to determine whether a record of the second database is identical to the first record.

2. The computer implemented method of claim 1 wherein the code comprises a hash number computed based on at least a portion of the content of the record of the first database.

3. A computer program, resident on a computer readable medium, for identifying a record of a first database stored on a first computer to a second computer storing a second database, as part of a process of synchronizing the first and second databases, comprising instructions

for reading a first record of the first database;

assigning a code to the first record of the first database, the code being based on at least a portion of the content of the first record of the first database, the code being insufficient to reconstruct the record but sufficient to identify the record;

transmitting the code to the second computer to identify the first record to the second computer; and

using the code in the synchronization process to determine whether a record of the second database is identical to the first record.

4. The computer program of claim 3 wherein the code comprises a hash number computed based on at least a portion of the content of the record of the first database.