Method and system for partition level cleanup of replication conflict metadata

• US 20060095481A1
• Filed: 11/04/2004
• Published: 05/04/2006
• Est. Priority Date: 11/04/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Vaughn, Philip Austin, Singh, Ram Pratap
• Granted Patent: US 7,933,868 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/278 Data partitioning, e.g. horizontal or vertical partitioning

Abstract

A method of removing metadata from a database in a multimode replication system includes establishing a metadata retention period for nodes in the system as well as associating changes with nodes on the system. The system responds to an expiration of the retention period for any one node by analyzing the associated changes and nodes and determining if the change affects data shared with other nodes. If the data is shared with other nodes then the expired retention period node metadata is removed from the system. If the expired metadata retention period node does not share the changes with other nodes, the metadata is not removed. This allows any unique changes to still be entered into the database without adversely affecting other nodes.

Claims

1. A method of removing metadata from a database in a multimode replication system, the method comprising:

establishing a metadata retention period for nodes in the system, wherein once the metadata retention period expires for a node, metadata concerning conflict resolution for the node is discarded;

associating data changes with nodes, wherein a change to a portion of database data made by the node is mapped to other interested nodes, such that the node and the other interested nodes can receive updated changes to the portion of database data;

removing conflict resolution metadata corresponding to the node if a metadata retention period for the node has expired and other interested nodes are included in the association of data changes; and

avoiding the removal of conflict resolution metadata in any node for which other interested nodes are absent.

2. The method of claim 1, wherein associating data changes with nodes further comprises generating a change-to-node mapping.

3. The method of claim 1, further comprising time tagging the generation of each change to database data made by a node.

4. The method of claim 1, further comprising accepting changes of database data from a node with an expired retention period if the changes of database data are not actively used by another node.

5. A system for replicating data which includes a metadata management, the system comprising:

a database;

at least two nodes, the nodes capable of downloading partitions of the database data;

means for executing instructions, the instructions performing a method comprising;

establishing a metadata retention period for nodes in the system, wherein once the metadata retention period expires for a node, metadata concerning conflict resolution for the node is discarded;

associating data changes with nodes, wherein a change to a portion of database data made by the node is mapped to other interested nodes, such that the node and the other interested nodes can receive updated changes to the portion of database data by generating a change-to-node mapping;

removing conflict resolution metadata corresponding to the node if a metadata retention period for the node has expired and other interested nodes are included in the association of data changes; and

avoiding the removal of conflict resolution metadata in any node for which other interested nodes are absent.

6. The system of claim 5, wherein the method further comprises accepting changes of database data from a node with an expired retention period if the changes of database data are not actively used by another node.

7. A computer-readable medium having computer-executable instructions for performing a method for removing metadata from a database in a multimode replication system, the method comprising:

establishing a metadata retention period for nodes in the system, wherein once the metadata retention period expires for a node, metadata concerning conflict resolution for the node is discarded;

associating data changes with nodes, wherein a change to a portion of database data made by the node is mapped to other interested nodes, such that the node and the other interested nodes can receive updated changes to the portion of database data;

removing conflict resolution metadata corresponding to the node if a metadata retention period for the node has expired and other interested nodes are included in the association of data changes; and

avoiding the removal of conflict resolution metadata in any node for which other interested nodes are absent.

8. The computer-readable medium of claim 7, wherein the method step of associating data changes with nodes further comprises generating a change-to-node mapping.

9. The computer-readable medium of claim 7, wherein the method step further comprises time tagging the generation of each change to database data made by a node.

10. The computer-readable medium of claim 7, wherein the method step further comprises accepting changes of database data from a node with an expired retention period if the changes of database data are not actively used by another node.