Apparatus and method for handling backend failover in an application server

• US 20060173866A1
• Filed: 02/03/2005
• Published: 08/03/2006
• Est. Priority Date: 02/03/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Newport, William T.
• Granted Patent: US 8,327,003 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

An application server includes a connection pool that specifies a number of allowable connections, and includes a backend failure detection mechanism and a backend failure recovery mechanism. When the backend failure detection mechanism detects that the backend fails, applications waiting on the hung connections may be notified of the backend failure. The backend failure detection mechanism will then detect when the backend recovers and becomes available once again. Once the backend is available again, the backend failure recovery mechanism increases the number of connections in the connection pool to compensate for the hung connections. As each hung connection is timed out using a network timeout mechanism, the number of allowable connections is reduced. Eventually all of the hung connections will time out, with the result being that the connection pool will contain the same specified number of allowable connections it originally had before the backend failed.

Claims

1. An apparatus comprising:

at least one processor;

a memory coupled to the at least one processor;

an application server residing in the memory and executed by the at least one processor, the application server comprising;

a connection pool that specifies a number of allowable connections to a backend;

a backend failure detection mechanism that detects when the backend fails; and

a backend failure recovery mechanism that increases the specified number of allowable connections in the connection pool when the backend fails.

2. The apparatus of claim 1 wherein the backend failure recovery mechanism temporarily increases the specified number of allowable connections in the connection pool when the backend fails.

3. The apparatus of claim 2 wherein, after the backend recovers from the failure, the backend failure recovery mechanism reduces the specified number of allowable connections in the connection pool to the specified number of allowable connections in the connection pool before the backend failure.

4. The apparatus of claim 3 wherein the backend failure recovery mechanism decrements the specified number of allowable connections in the connection pool each time a network timeout mechanism indicates a connection in the connection pool has timed out.

5. The apparatus of claim 1 wherein the backend failure detection mechanism comprises a heartbeat mechanism that periodically determines if the backend is responsive to a request to the backend.

6. The apparatus of claim 1 wherein the backend failure recovery mechanism increases the specified number of allowable connections in the connection pool by the number of connections in use in the connection pool when the backend fails.

7. A computer-implemented method for an application server to handle failure of a backend coupled to the application server, the method comprising the steps of:

(A) detecting when the backend fails; and

(B) when the backend fails, increasing a specified number of allowable connections in a connection pool to the backend.

8. The method of claim 7 wherein the increase in the specified number of allowable connections in the connection pool in step (B) is temporary.

9. The method of claim 8 further comprising the steps of:

detecting when the backend recovers from the failure; and

in response to the backend recovering from the failure, reducing the specified number of allowable connections in the connection pool to the specified number of allowable connections in the connection pool before the backend failure.

10. The method of claim 9 further comprising the step of decrementing the specified number of allowable connections in the connection pool each time a network timeout mechanism indicates a connection in the connection pool has timed out.

11. The method of claim 7 wherein step (A) comprises the step of periodically determining if the backend is responsive to a request to the backend.

12. The method of claim 7 wherein step (B) comprises the step of increasing the specified number of allowable connections in the connection pool by the number of connections in use in the connection pool when the backend fails.

13. A program product comprising:

(A) an application server comprising;

a connection pool that specifies a number of allowable connections to a backend;

a backend failure detection mechanism that detects when the backend fails; and

a backend failure recovery mechanism that increases the specified number of allowable connections in the connection pool when the backend fails; and

(B) computer-readable signal bearing media bearing the application server.

14. The program product of claim 13 wherein the computer-readable signal bearing media comprises recordable media.

15. The program product of claim 13 wherein the computer-readable signal bearing media comprises transmission media.

16. The program product of claim 13 wherein the backend failure recovery mechanism temporarily increases the specified number of allowable connections in the connection pool when the backend fails.

17. The program product of claim 16 wherein, after the backend recovers from the failure, the backend failure recovery mechanism reduces the specified number of allowable connections in the connection pool to the specified number of allowable connections in the connection pool before the backend failure.

18. The program product of claim 17 wherein the backend failure recovery mechanism decrements the specified number of allowable connections in the connection pool each time a network timeout mechanism indicates a connection in the connection pool has timed out.

19. The program product of claim 13 wherein the backend failure detection mechanism comprises a heartbeat mechanism that periodically determines if the backend is responsive to a request to the backend.

20. The program product of claim 13 wherein the backend failure recovery mechanism increases the specified number of allowable connections in the connection pool by the number of connections in use in the connection pool when the backend fails.