System and method for synchronizing database in a primary device and a secondary device that are derived from a common database

• US 6,493,727 B1
• Filed: 02/07/2000
• Issued: 12/10/2002
• Est. Priority Date: 02/07/2000
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Koontz, Michael D., Caccia, Marco, Huang, Andrew J.
• Primary Examiner(s): Breene, John
• Assistant Examiner(s): Wong, Leslie
• Application Number:
  US09/499,322
• Time in Patent Office: 1,037 Days
• Field of Search: 707/1-206
• US Class Current: 707/610
• 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: Y10S 707/99952 Coherency, e.g. same view to multiple users

Abstract

A system and method are provided for maintaining a common consistent database in a primary device and in a secondary device. The method includes the steps of determining a need for a merger of a first database maintained in the primary device and a second database maintained in the secondary device, the first and second databases being derived from common database. The method also includes the steps of merging the first database and the second database, resulting in a merged database and assigning a sequence identifier to the merged database. Finally the present method includes the step of synchronizing the merged database in the primary and secondary devices.

Claims

1. A method for maintaining a database in a primary device and in a secondary device, comprising the steps of:

determining a need for a merger of a first database maintained in the primary device and a second database maintained in the secondary device, wherein the first and second databases are derived from a common database;

maintaining a primary dirty flag in the primary device, the primary dirty flag indicating that a content of the first database has been altered and potentially does not coincide with a content of the second database maintained in the secondary device;

merging the first database and the second database, resulting in a merged database;

assigning a sequence identifier to the merged database; and

synchronizing the merged database in the primary and secondary devices by transmitting the merged database in its entirety and the sequence identifier from the primary device to the secondary device.

2. The method of claim 1, wherein the step of determining a need for a merger further comprises the step of setting a primary dirty flag upon an occurrence of an alteration to the first database.

3. The method of claim 1, wherein the step of determining a need for a merger further comprises the step of setting a secondary dirty flag upon an occurrence of an alteration to the second database.

4. The method of claim 1, wherein the step of determining a need for a merger further comprises the step of transmitting an alteration status of the second database in the secondary device to the primary device, the alteration status being indicated by a state of a secondary dirty flag.

5. A system in a primary device for maintaining a database in the primary device and in a secondary device, comprising:

a processor electrically coupled to a local interface;

a memory electrically coupled to the local interface; and

primary synchronization logic stored on the memory and executed by the processor, the primary synchronization logic including;

logic to determine a need for a merger of a first database maintained in the primary device and a second database maintained in the secondary device, where the first and second databases are derived from a common database;

a primary dirty flag maintained in the memory that indicates that a content of the first database has been altered and potentially does not coincide with a content of the second database maintained in the secondary device;

logic to merge the first and second databases, resulting in a merged database;

logic to assign a sequence identifier to the merged database; and

logic to synchronize the merged database in the primary and secondary devices by transmitting the merged database in its entirety and the sequence identifier from the primary device to the secondary device.

6. The system of claim 5, further comprising logic to set a primary dirty flag to indicate an occurrence of an alteration to the first database.

7. The system of claim 5, wherein the primary synchronization logic further comprises logic to detect a secondary dirty flag received from the secondary device.

8. A system in a primary device for maintaining a database in the primary device and in a secondary device, comprising:

means for determining a need for a merger of a first database maintained in the primary device and a second database maintained in the secondary device, where the first and second databases are derived from a common database;

means for maintaining a primary dirty flag that indicates that a content of the first database has been altered and potentially does not coincide with a content of the second database maintained in the secondary device;

means for merging the first and second databases, resulting in a merged database;

means for assigning a sequence identifier to the merged database; and

means for synchronizing the merged database in the primary and secondary devices by transmitting the merged database in its entirety and the sequence identifier from the primary device to the secondary device.

9. A system in a secondary device for maintaining a database in a primary device and in the secondary device, comprising:

a processor electrically coupled to a local interface;

a memory electrically coupled to the local interface;

secondary synchronization logic stored on the memory executed by the processor, the secondary synchronization logic including;

logic to receive and store a second database from the primary device, the second database being identical to a first database stored in the primary device;

logic to receive and store a sequence identifier from the primary device, the sequence identifier being associated with the second database;

logic to maintain an alteration status of the second database; and

logic to detect an alteration status request from the primary device and to transmit the alteration status of the second database to the primary device in response to the alteration status request.

10. The system of claim 9, wherein the logic to maintain an alteration status of the second database further comprises logic to maintain a state of a secondary dirty flag.

11. A system in a secondary device for maintaining a database in a primary device and in the secondary device, comprising:

means for receiving and storing a second database from the primary device, the second database being identical to a first database stored in the primary device;

means for receiving and storing a sequence identifier from the primary device, the sequence identifier being associated with the second database;

means for maintaining an alteration status of the second database; and

means for detecting an alteration status request from the primary device and for transmitting the alteration status of the second database to the primary device in response to the alteration status request.

12. A method in a secondary device for maintaining a database in a primary device and in the secondary device, comprising:

receiving and storing a second database from the primary device, the second database being identical to a first database stored in the primary device;

receiving and storing a sequence identifier from the primary device, the sequence identifier being associated with the second database;

maintaining an alteration status of the second database; and

detecting an alteration status request from the primary device and transmitting the alteration status of the second database to the primary device in response to the alteration status request.