Dynamic synchronization of tables

• US 7,516,165 B2
• Filed: 10/27/2004
• Issued: 04/07/2009
• Est. Priority Date: 06/29/1999
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Christofferson, Peter A., Berkowitz, Brian T.
• Primary Examiner(s): NGUYEN, CAM LINH T
• Application Number:
  US10/975,932
• Publication Number:
  US 20050091240A1
• Time in Patent Office: 1,623 Days
• Field of Search: 707/200, 707/201, 707/203, 715/500.1, 709/231, 370/464
• US Class Current: 1/1
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99936 Pattern matching access
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

Each node in a network accessing a common database caches a copy of the database tables it uses and updates those tables based on changes made by other nodes in a coherent cache, i.e., those node that also have a copy of the tables in their cache. When a new node joins the coherent cache, dynamic synchronization of the table is performed by having one of the existing nodes act as a source to populate the table(s) required on the new (destination) node from its own copy. The dynamic synchronization controls the population operation and allows for the populating of tables on the destination node from partially populated tables on the source node. The dynamic synchronization of the tables permits database updates to continue to be made to the tables by the existing nodes in the coherent cache and provides a mechanism to propagate the committed updates to the tables on the destination node. Once the tables on the destination node are fully populated, all pending updates are suspended while a snapshot of the state of the table on the source node is taken. Once the destination node has processed the snapshot, active transactions on the source node are initiated on the destination node, and all transactions are allowed to modify the table on the destination node.

Claims

1. A network computer system comprising:

a source node computer comprising;

a source node processing unit coupled to a network through a system bus;

a source node system memory coupled to the source node processing unit through a system bus, wherein a table identically shared among computers on the network is cached in the source node system memory;

a source node computer-readable medium coupled to the source node processing unit through a system bus; and

a synchronization source process executed from the source node computer-readable medium by the source node processing unit, wherein the synchronization source process causes the source node processing unit to create a synchronization stream from data for the shared table and to transmit the synchronization stream on the network; and

a destination node computer comprising;

a destination node processing unit coupled to the network through a system bus;

a destination node system memory coupled to the destination node processing unit through a system bus;

a destination node computer-readable medium coupled to the destination node processing unit through a system bus; and

a synchronization destination process executed from the destination node computer-readable medium by the destination node processing unit, wherein the synchronization destination process causes the destination node processing unit to receive the synchronization stream from the network and to create a copy of the shared table in the destination node system memory, wherein the synchronization destination process creates the copy on the destination node which is identical to the table already shared among computers on the network, the copy including transactions which are committed during the synchronization destination process.

2. The network computer system of claim 1, wherein the synchronization source process further causes the source node processing unit to place a first message on the network, and the synchronization destination process further causes the destination node processing unit to initiate a process associated with the first message and to respond to the first message when the process is complete.

3. The network computer system of claim 2, wherein the synchronization source process further causes the destination node processing unit to place a second message on the network in response to receiving the response to the first message from the destination node computer.

4. The network computer system of claim 2, wherein the synchronization stream is transmitted on a dedicated channel and the messages sent between the synchronization source computer and the destination source computer are transmitted on a normal messaging channel.

5. A method for synchronizing data on a network computer system comprising a source node computer and a destination node computer,

wherein the source node computer comprises a source node processing unit coupled to a network, a source node system memory coupled to the source node processing unit, and a source node computer-readable medium coupled to the source node processing unit, and

wherein the destination node computer comprises a destination node processing unit coupled to the network, a destination node system memory coupled to the destination node processing unit, and a destination node computer-readable medium coupled to the destination node processing unit;

the method comprising;

caching a table shared among computers on the network in the source node system memory;

executing a synchronization source process from the source node computer -readable medium, wherein the synchronization source process causes the source node processing unit to create a synchronization stream from data for the shared table and to transmit the synchronization stream on the network; and

executing a synchronization destination process from the destination node computer-readable medium, wherein the synchronization destination process causes the destination node processing unit to receive the synchronization stream from the network and to create a copy of the shared table in the destination node system memory, wherein the synchronization destination process creates the copy on the destination node which is identical to the table already shared among computers on the network, the copy including transactions which are committed during the synchronization destination process.

6. The method of claim 5, wherein the synchronization source process further causes the source node processing unit to place a first message on the network, and the synchronization destination process further causes the destination node processing unit to initiate a process associated with the first message and to respond to the first message when the process is complete.

7. The method of claim 6, wherein the synchronization source process further causes the destination node processing unit to place a second message on the network in response to receiving the response to the first message from the destination node computer.

8. The method of claim 6, wherein the synchronization stream is transmitted on a dedicated channel and the messages sent between the synchronization source computer and the destination source computer are transmitted on a normal messaging channel.

9. One or more computer-readable media containing instructions which, when executed by one or more computers, cause the computers to execute a method for synchronizing data on a network computer system comprising a source node computer and a destination node computer,

wherein the source node computer comprises a source node processing unit coupled to a network, a source node system memory coupled to the source node processing unit, and a source node computer-readable medium coupled to the source node processing unit, and

wherein the destination node computer comprises a destination node processing unit coupled to the network, a destination node system memory coupled to the destination node processing unit, and a destination node computer-readable medium coupled to the destination node processing unit;

the method comprising;

caching a table shared among computers on the network in the source node system memory;

executing a synchronization source process from the source node computer -readable medium, wherein the synchronization source process causes the source node processing unit to create a synchronization stream from data for the shared table and to transmit the synchronization stream on the network; and

executing a synchronization destination process from the destination node computer-readable medium , wherein the synchronization destination process causes the destination node processing unit to receive the synchronization stream from the network and to create a copy of the shared table in the destination node system memory, wherein the synchronization destination process creates the copy on the destination node which is identical to the table already shared among computers on the network, the copy including transactions which are committed during the synchronization destination process.

10. The computer-readable media of claim 9, wherein the synchronization source process further causes the source node processing unit to place a first message on the network, and the synchronization destination process further causes the destination node processing unit to initiate a process associated with the first message and to respond to the first message when the process is complete.

11. The computer-readable media of claim 10, wherein the synchronization source process further causes the destination node processing unit to place a second message on the network in response to receiving the response to the first message from the destination node computer.

12. The computer-readable media of claim 10, wherein the synchronization stream is transmitted on a dedicated channel and the messages sent between the synchronization source computer and the destination source computer are transmitted on a normal messaging channel.