Reducing database downtime

• US 9,183,088 B2
• Filed: 03/08/2011
• Issued: 11/10/2015
• Est. Priority Date: 03/31/2010
• Status: Active Grant

• Current Assignee: Salesforce.com, Inc.
• Original Assignee: Salesforce.com, Inc.
• Inventors: Yancey, Scott, Jain, Chandni, Noorthoek, Gerard
• Primary Examiner(s): Wu, Yicun
• Application Number:
  US13/043,276
• Publication Number:
  US 20110246419A1
• Time in Patent Office: 1,708 Days
• Field of Search: 707/624, 707/640, 707/655
• US Class Current: 1/1
• CPC Class Codes: G06F 11/14 Error detection or correction of the data by redundancy in operation G06F11/16 takes precedence
• CPC Class Codes: G06F 16/211 Schema design and management
• CPC Class Codes: G06F 16/2343 Locking methods, e.g. distributed locking or locking implementation details
• CPC Class Codes: G06F 16/2358 Change logging, detection, and notification replication G06F16/27
• CPC Class Codes: G06F 16/2379 Updates performed during online database operations; commit processing
• CPC Class Codes: G06F 16/25 Integrating or interfacing systems involving database management systems
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: G06F 16/951 Indexing; Web crawling techniques

Abstract

Embodiments enable reduction of database downtime in a live production environment of an on-demand database service during repair and/or maintenance tasks. A source database and a target database are provided. Data is copied from the source database to the target database to create a mirrored set of data. Access is limited to one or more designated tables in the target database. General traffic is redirected from the source database to the target database, wherein the redirection occurs for a duration of a maintenance period. Data modifications that occur in the target database during the maintenance period are captured and then replicated into the source database. Finally, general traffic is redirected from the target database to the source database.

Claims

1. A computer-implemented method of reducing database downtime for online applications, the method comprising:

copying data, using one or more processors associated with one or more servers, from a source database to a target database to create a mirrored set of data;

limiting access to one or more designated tables in the target database, wherein database-level triggers are created for all tables for which access is to be restricted and the triggers operate to restrict a database access to sanctioned operations through implementation of a special database user, wherein the database trigger raises an exception for every INSERT, UPDATE, or DELETE attempt and the database trigger permits temporary or short-term modifications to data that are not to be copied back to the source database;

redirecting general traffic from the source database to the target database, wherein the redirection occurs for a duration of a maintenance period;

capturing, using the one or more processors associated with the one or more servers, data modifications occurring in the target database during the maintenance period;

replicating, using the one or more processors associated with the one or more servers, the data modifications into the source database; and

redirecting general traffic from the target database to the source database.

2. The method of claim 1, wherein the general traffic comprises requests received via one of a web server, an application server, a function call to an application programming interface, and a local application.

3. The method of claim 1, wherein limiting access to a table comprises permitting only read access.

4. The method of claim 1, wherein limiting access to the one or more designated tables in the target database comprises:

configuring properties for a limited user of the target database indicating that access to the one or more designated tables is to be limited;

configuring database-level triggers in the target database to check user properties to determine access permissions; and

configuring properties related to the general traffic to access the target database through the limited user.

5. The method of claim 1, further comprising:

receiving a request via general traffic related to a table designated for limited access; and

transmitting information to display an indication that access to information is limited.

6. The method of claim 5, wherein the indication that access to information is limited comprises modifying or removing a button or link to permit edits to information.

7. The method of claim 1, wherein copying data from the source database to the target database comprises continually updating the target database in real-time until a cutover process is initiated.

8. The method of claim 1, wherein copying data from the source database to the target database comprises a single batch process performed immediately prior to redirecting general traffic from the source database to the target database.

9. The method of claim 1, wherein redirecting general traffic comprises configuring one or more load balancers.

10. The method of claim 1, further comprising concurrently permitting the administrative traffic to access the source database while redirecting the general traffic from the source database to the target database.

11. The method of claim 10, further comprising determining whether a request is related to general traffic or administrative traffic based on the IP address of the request.

12. The method of claim 1, wherein replicating the data modifications into the source database comprises mapping data in accordance with differences between a data schema of the source database and a data schema of the target database.

13. A system for reducing database downtime for online applications, the system comprising:

a network interface;

a non-transitory computer-readable medium tangibly embodied with program code; and

one or more servers, including one or more processors, for executing the program code, the program code comprising;

instructions to copy data from a source database to a target database to create a mirrored set of data;

instructions to access to one or more designated tables in the target database, wherein database-level triggers are created for all tables for which access is to be restricted and the triggers operate to restrict a database access to sanctioned operations through implementation of a special database user, wherein the database trigger raises an exception for every INSERT, UPDATE, or DELETE attempt and the database trigger permits temporary or short-term modifications to data that are not to be copied back to the source database;

instructions to redirect general traffic from the source database to the target database, wherein the redirection occurs for a duration of a maintenance period;

instructions to capture data modifications occurring in the target database during the maintenance period;

instructions to replicate the data modifications into the source database; and

instructions to redirect general traffic from the target database to the source database.

14. The system of claim 13, wherein the general traffic comprises requests received via one of a web server, an application server, a function call to an application programming interface, and a local application.

15. The system of claim 13, wherein the instructions to limit access to a table comprises instructions to permit only read access.

16. The system of claim 13, wherein the instructions to limit access to the one or more designated tables in the target database comprises:

instructions to configure properties for a limited user of the target database indicating that access to the one or more designated tables is to be limited;

instructions to configure database-level triggers in the target database to check user properties to determine access permissions; and

instructions to configure properties related to the general traffic to access the target database through the limited user.

17. The system of claim 13, further comprising:

instructions to receive a request via general traffic related to a table designated for limited access; and

instructions to transmit information to display an indication that access to information is limited.

18. The system of claim 17, wherein the indication that access to information is limited comprises modifying or removing a button or link to permit edits to information.

19. The system of claim 13, wherein the instructions to copy data from the source database to the target database comprises instructions to continually update the target database in real-time until a cutover process is initiated.

20. The system of claim 13, wherein the instructions to copy data from the source database to the target database comprises instructions to perform a single batch process immediately prior to redirecting general traffic from the source database to the target database.

21. The system of claim 13, wherein the instructions to redirect general traffic comprises instructions to configure one or more load balancers.

22. The system of claim 13, further comprising instructions to concurrently permit the administrative traffic to access the source database while redirecting the general traffic from the source database to the target database.

23. The system of claim 22, further comprising instructions to determine whether a request is related to general traffic or administrative traffic based on the IP address of the request.

24. The system of claim 13, wherein the instructions to replicate the data modifications into the source database comprises instructions to map data in accordance with differences between a data schema of the source database and a data schema of the target database.

25. A non-transitory computer-readable medium containing program code executable by a processor in a computer to reduce database downtime for online applications, the program code including instructions to:

copy data, using one or more processors associated with one or more servers, from a source database to a target database to create a mirrored set of data;

limit access to one or more designated tables in the target database, wherein database-level triggers are created for all tables for which access is to be restricted and the triggers operate to restrict a database access to sanctioned operations through implementation of a special database user, wherein the database trigger raises an exception for every INSERT, UPDATE, or DELETE attempt and the database trigger permits temporary or short-term modifications to data that are not to be copied back to the source database;

redirect general traffic from the source database to the target database, wherein the redirection occurs for a duration of a maintenance period;

capture, using the one or more processors associated with the one or more servers, data modifications occurring in the target database during the maintenance period;

replicate, using the one or more processors associated with the one or more servers, the data modifications into the source database; and

redirect general traffic from the target database to the source database.

26. The non-transitory computer-readable medium of claim 25, wherein the general traffic comprises requests received via one of a web server, an application server, a function call to an application programming interface, and a local application.

27. The non-transitory computer-readable medium of claim 25, wherein the instructions to limit access to a table comprises instructions to permit only read access.

28. The non-transitory computer-readable medium of claim 25, wherein the instructions to limit access to the one or more designated tables in the target database comprises:

instructions to configure properties for a limited user of the target database indicating that access to the one or more designated tables is to be limited;

instructions to configure database-level triggers in the target database to check user properties to determine access permissions; and

instructions to configure properties related to the general traffic to access the target database through the limited user.

29. The non-transitory computer-readable medium of claim 25, further comprising:

instructions to receive a request via general traffic related to a table designated for limited access; and

instructions to transmit information to display an indication that access to information is limited.

30. The non-transitory computer-readable medium of claim 29, wherein the indication that access to information is limited comprises modifying or removing a button or link to permit edits to information.

31. The non-transitory computer-readable medium of claim 25, wherein the instructions to copy data from the source database to the target database comprises instructions to continually update the target database in real-time until a cutover process is initiated.

32. The non-transitory computer-readable medium of claim 25, wherein the instructions to copy data from the source database to the target database comprises instructions to perform a single batch process immediately prior to redirecting general traffic from the source database to the target database.

33. The non-transitory computer-readable medium of claim 25, wherein the instructions to redirect general traffic comprises instructions to configure one or more load balancers.

34. The non-transitory computer-readable medium of claim 25, further comprising instructions to concurrently permit the administrative traffic to access the source database while redirecting the general traffic from the source database to the target database.

35. The non-transitory computer-readable medium of claim 34, further comprising instructions to determine whether a request is related to general traffic or administrative traffic based on the IP address of the request.

36. The non-transitory computer-readable medium of claim 25, wherein the instructions to replicate the data modifications into the source database comprises instructions to map data in accordance with differences between a data schema of the source database and a data schema of the target database.