RECONCILIATION OF GEO-REPLICATED DATABASE CLUSTERS

• US 20140258229A1
• Filed: 03/05/2013
• Published: 09/11/2014
• Est. Priority Date: 03/05/2013
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Verbitski, Alexandre, Talius, Tomas, Xia, Hao, Voutilainen, Santeri, Nelson, Michael, Kuchibhotla, Sree, Shah, Vishrut
• Granted Patent: US 9,405,816 B2
• Time in Patent Office: Days
• US Class Current: 707/634
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation

Abstract

A database associated with a primary database cluster may be replicated in a backup database cluster located in a different location in order to provide a highly-available fault tolerant database service. The databases are reconciled through a cluster management module distributed in each database cluster. The cluster management module uses a set of reconciliation data structures to track locally the reconciled states of each database in each database cluster, the operations made locally to the databases in each database cluster, and the author of the operations. The cluster management module in each database cluster engages in a stateless messaging protocol using the set of reconciliation data structures to determine whether or not the databases may be reconciled.

Claims

1. A computer-implemented method, the method comprising:

configuring a primary database in a primary database cluster to be replicated in a secondary database in a secondary database cluster;

tracking, at the primary database cluster, a current statename and previous statename of the primary database, the current statename representing a current state, the previous statename representing a state immediately prior to the current state;

tracking, at the secondary database cluster, a current statename and a previous statename of the secondary database;

generating a new statename of the primary database when a user performs an operation on the primary database;

receiving, at the secondary database cluster, a current statename and a new statename of the primary database; and

determining, at the secondary database cluster, whether to reconcile the primary database to the secondary database based on a current statename of the secondary database, the current statename of the primary database, and the new statename of the primary database, and a previous statename of the secondary database.

2. The computer-implemented method of claim 1, further comprising:

tracking, at the primary database cluster, when a system performs an operation on the primary database;

tracking, at the secondary database cluster, when a system performs an operation on the secondary database; and

reconciling the primary database with the secondary database when a current statename of the primary database matches a current statename of the secondary database and no system operations have been performed on the primary database or the secondary database since a last reconciliation between the primary database and the secondary database.

3. The computer-implemented method of claim 2, further comprising:

delaying reconciliation of the primary database with the secondary database when a current statename of the primary database matches a current statename of the secondary database and there is at least one system operation performed on the primary database or the secondary database since the last reconciliation.

4. The computer-implemented method of claim 1, further comprising:

rejecting reconciliation of the primary database with the secondary database when a current statename of the primary database does not match a current statename of the secondary database and a current statement of the primary database does not match a previous statename of the secondary database.

5. The computer-implemented method of claim 1, further comprising:

forcing an operation to be performed on the secondary database without reconciliation with the primary database; and

requesting the primary database to reconcile with the secondary database.

6. The computer-implemented method of claim 5, further comprising:

prior to requesting the primary database to reconcile with the secondary database;

replacing a previous statename associated with the secondary database with a current statename of the secondary database; and

generating a new state for the current statename for the secondary database.

7. The computer-implemented method of claim 1, further comprising:

tracking, at the primary database cluster, when a system performs an operation on the primary database since a last reconciliation;

tracking, at the secondary database cluster, when a system performs an operation on the secondary database since a last reconciliation; and

reconciling the primary database with the secondary database when a current statename of the secondary database matches a previous statename of the primary database and no system operations have been performed on the primary database and the secondary database since a last reconciliation.

8. A computer-readable storage medium storing thereon processor-executable instructions, comprising:

a first set of processor-executable instructions that when executed on a processor, establishes a relationship between a primary database in a primary database cluster with a secondary database in a secondary database cluster, the relationship having operations performed on the primary database replicated in the secondary database, the primary database cluster and the secondary database cluster located in a different geographic location;

a second set of processor-executable instructions that when executed on a processor, tracks a current state and a previous state of a secondary database in a secondary database cluster;

a third set of processor-executable instructions that when executed on a processor, receives a current state and a new state of the primary database, the current state and new state of the primary database tracked by the primary database cluster; and

a fourth set of processor-executable instructions that when executed on a processor, determines whether operations performed on the primary database may be reconciled with the secondary database based on a current state of the primary database, a current state of the secondary database in the secondary database, a new state of the primary database, and a previous state of the secondary database.

9. The computer-readable storage medium of claim 8, further comprising:

a fifth set of processor-executable instructions that when executed on a processor, determines that operations associated with a new state of the primary database may be reconciled with the secondary database when the current state of the primary database matches the current state of the secondary database.

10. The computer-readable storage medium of claim 8, further comprising:

a seventh set of processor-executable instructions that when executed on a processor, forces the secondary database to perform operations on the secondary database that are not reconciled with the primary database.

11. The computer-readable storage medium of claim 10, further comprising:

an eighth set of processor-executable instructions that when executed on a processor, receives a request from the primary database to reconcile with the primary database and in response to the request, sends the primary database a request to reconcile with the secondary database.

12. The computer-readable storage medium of claim 8, further comprising:

a ninth set of processor-executable instructions that when executed on a processor, reconciles operations performed on the primary database when a current state of the primary database matches a previous state of the secondary database.

13. The computer-readable storage medium of claim 8, further comprising:

a tenth set of processor-executable instructions that when executed on a processor, terminates the relationship between the primary database and the secondary database when a current state of the primary database does not match a current state of the secondary database and the current state of the primary database does not match a previous state of the secondary database.

14. The computer-readable storage medium of claim 13, further comprising:

a eleventh set of processor-executable instructions that when executed on a processor, allows a user to force operations to be performed on the secondary database thereby updating the current state and previous state of the secondary database without reconciliation with the primary database.

15. The computer-readable storage medium of claim 13, further comprising:

a twelfth set of processor-executable instructions that when executed on a processor, tracks on the secondary database cluster when a system performs an operation on the secondary database and adjusts the current state of the secondary database to reflect the operation.

16. A system, comprising:

a plurality of database clusters, each database cluster having one or more databases and at least one server, the server including a cluster management module,

the cluster management module, having processor-executable instructions that when executed on a processor;

establishes a relationship between a primary database in one database cluster with a secondary database in another database cluster for the primary database to be replicated in the secondary database,

allows a user and a system to perform one or more operations on each database independently,

tracks a current state, a new state, and a previous state of the primary and secondary databases in each cluster, and

reconciles operations performed on the primary database with the secondary database based on a current state, new state and previous state of the primary database and a current state, new state and previous sate of the secondary database.

17. The system of claim 16, wherein the database clusters communicate through a stateless communication protocol.

18. The system of claim 16, wherein the primary database is hosted on a primary database cluster and the secondary database is hosted on a secondary database cluster, the primary database cluster located in a different geographic location than the secondary database cluster.

19. The system of claim 16, wherein the primary database is hosted on a primary database cluster and the secondary database is hosted on a secondary database cluster, the primary database cluster located at a same geographic location as the secondary database cluster.

20. The system of claim 16, wherein the cluster management module terminates the relationship between the primary database and the secondary database when the current state of the primary database does not match the current state of the secondary database and the current state of the primary database does not match the previous state of the secondary database.