MIRRORING DATA CHANGES IN A DATABASE SYSTEM

• US 20120041928A1
• Filed: 08/16/2010
• Published: 02/16/2012
• Est. Priority Date: 08/16/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Kamra, Vaibhav, Madhavarapu, Pradeep, Diaconu, Cristian, Fang, Jun, Chirica, Alexandru, Porwal, Priyank, Acharya, Srimvasmurthy
• Granted Patent: US 8,655,847 B2
• Time in Patent Office: Days
• US Class Current: 707/656
• 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: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: G06F 16/275 Synchronous replication

Abstract

A method for mirroring one or more data changes from a first database server to one or more second database servers. The method includes intercepting one or more operations that make one or more changes to one or more data on the first database server. After intercepting these operations, the method merges the operations into one or more chunks, adds one or more log records having the chunks into a database log. The database log includes one or more database log blocks. The method then writes the database log blocks.

Claims

1. A method for mirroring one or more data changes from a first database server to one or more second database servers, comprising:

intercepting one or more operations that make one or more changes to one or more data on the first database server;

merging the operations into one or more chunks;

adding one or more log records having the chunks into a database log, the database log having one or more database log blocks; and

writing the database log blocks.

2. The method of claim 1, wherein the operations are intercepted by a filter driver.

3. The method of claim 2, wherein the filter driver is a kernel mode driver configured to detect the changes.

4. The method of claim 1, wherein the operations are from a filesystem stack.

5. The method of claim 4, wherein the operations comprise open, write and close operations on the data.

6. The method of claim 1, wherein the operations are from a database stack.

7. The method of claim 6, wherein the operations comprise insert and update operations on the data.

8. The method of claim 1, wherein intercepting the operations comprises:

detecting the operations that make the changes;

determining an offset location and a length for each change; and

sending the offset location and the length for each change to a chunker.

9. The method of claim 8, wherein the operations are merged by the chunker.

10. The method of claim 1, wherein merging the operations comprises combining a subset of the operations, wherein the subset of the operations comprises two or more data changes, wherein each data change in the subset occurs nearby each other.

11. The method of claim 1, wherein the merged operations are represented by an offset location and a length.

12. The method of claim 1, wherein the operations are merged after a predetermined amount of time.

13. The method of claim 1, wherein the operations are merged for a predetermined amount of data.

14. The method of claim 1, further comprising sending the database log blocks to the second database servers.

15. The method of claim 14, wherein sending the database log blocks comprises:

(a) determining whether one of the database log blocks includes one of the log records having the chunks; and

(b) if the one of the database log blocks includes the one of the log records, then sending data that corresponds to the one of the log records to the second database servers.

16. The method of claim 15, further comprising repeating steps (a)-(b) for each database log block.

17. A database management system, comprising:

a filesystem filter driver configured to intercept one or more filesystem operations that make one or more changes to one or more data on the first database server;

a filestream manager configured to intercept one or more database operations that make one or more changes to the data;

a chunker configured to;

merge the filesystem operations and the database operations into one or more chunks;

add one or more log records having the chunks into a database log; and

write one or more database log blocks of the database log;

a log reader configured to;

read the database log blocks;

determine whether one of the database log blocks in the database log includes one of the log records having the chunks; and

if the one of the database log blocks includes the one of the log records, then send data that corresponds to the one of the log records to one or more second database management systems.

18. The database management system of claim 17, further comprising:

one or more database components configured to;

receive one or more notifications pertaining to the intercepted filesystem operations; and

send the notifications to the chunker, wherein the notifications comprise information related to the filesystem operations and the database operations.

19. The database management system of claim 18, wherein the chunker is configured to:

analyze the information to determine an offset location and a length for each change made by each filesystem operation and each database operation; and

merge two or more offset locations and two or more lengths, wherein the two or more offset location and the two or more lengths are adjacent to or overlapping with each other.

20. A method for mirroring one or more data changes from a first database server to one or more second database servers, comprising:

receiving one or more database log blocks from the first database server, wherein a first portion of the database log blocks refers to data in the first database server that has been changed;

receiving data that corresponds to the first portion of the database log blocks; and

replacing data stored on the second database servers with the received data.