Method and apparatus for migration of managed application state for a Java based application

• US 6,912,569 B1
• Filed: 04/30/2001
• Issued: 06/28/2005
• Est. Priority Date: 04/30/2001
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Sharma, Rahul, Krishnan, Sanjeev, Matena, Vladimir, Mortazavi, Masood
• Primary Examiner(s): Etienne, Ario
• Assistant Examiner(s): SALL, EL HADJI MALICK
• Application Number:
  US09/846,492
• Time in Patent Office: 1,520 Days
• Field of Search: 709/215, 709/223, 709/224, 709/203, 709/209, 709/231, 709/232, 719/315, 719/316, 707/8, 707/103, 707/202, 707/203, 707/204, 714/11, 714/13, 714/15, 714/16, 714/42
• US Class Current: 709/223
• CPC Class Codes: G06F 9/4493 Object persistence
• CPC Class Codes: G06F 9/4862 the task being a mobile agent, i.e. specifically designed to migrate

Abstract

An invention for migrating managed application state for a Java based application is disclosed. A first Java module is executed on a first server. The first Java module includes a first entity bean and a first state object in communication with the first entity bean. The first state object stores a state of the first entity bean. The first state object is replicated to a state server or stored in-memory and made capable of migration by replicated state manager. Then, a second Java module is started on a second server as part of the module migration by a control module. The second Java module includes a second state object that is populated with state by either recovering from replica of fist state object stored on the state server or by getting transferred state of an in-memory copy of first state object managed on first server.

Claims

1. A method for migrating managed state for a Java based application, comprising the operations of:

executing a first Java module on a first server, the first Java module including a first entity bean and a first state object in communication with the first entity bean, the first state object storing a state of the first entity bean;

replicating the first state object to a state server; and

starting a second Java module on a second server, the second Java module having a second state object.

2. A method as recited in claim 1, wherein the second state object obtains a related managed state through migration of state from the first server.

3. A method as recited in claim 1, wherein the second state object obtains a related managed state through recovery of the state replicated in the state server.

4. A method as recited in claim 1, wherein the state server is a memory replicated state server.

5. A method as recited in claim 1, wherein the state server is a disk replicated state server.

6. A method as recited in claim 1, wherein the second Java module further includes a second entity bean in communication with the second state object, wherein the second state object stores a state of the second entity bean.

7. A method as recited in claim 6, wherein checkpointing is used to replicate the first state object to the state server.

8. A method as recited in claim 7, wherein a migration-capable non-replicated state for the first entity bean is transferred to the second server.

9. A method as recited in claim 8, wherein a first replicated state manager executing on the first server transfers the migration-capable non-replicated state to a second replicated state manager executing on the second server.

10. A method as recited in claim 9, wherein the migration-capable non-replicated state is transferred using a replicated state manager specific transfer protocol.

11. A system for migrating managed state for a Java based application, comprising:

a first server executing a first Java module, wherein the first Java module includes a first entity bean and a first state object in communication with the first entity bean, the first state object storing a state of the first entity bean;

a state server in communication with the first server, the state server capable of managing replica of the first state object; and

a second server in communication with the state server and the first server, the second server capable of starting a second Java module having a second state object.

12. A system as recited in claim 11, wherein the second state object is populated with managed state using the replica of first state object on the state server.

13. A system as recited in claim 11, wherein the second state object is populated with managed state using a copy of the first state object as managed in memory by a replicated state manager.

14. A system as recited in claim 11, wherein the state server is a memory replicated state server.

15. A system as recited in claim 11, wherein the state server is a disk replicated state server.

16. A system as recited in claim 11, wherein the second Java module further includes a second entity bean in communication with the second state object, wherein the second state object stores a state of the second entity bean.

17. A system as recited in claim 16, wherein checkpointing is used to replicate the first state object to the state server.

18. A system as recited in claim 17, wherein a migration-capable non-replicated state for the first entity bean is transferred to the second server.

19. A system as recited in claim 18, further including a first replicated state manager executing of the first server, the first replicated state manager capable of providing the migration-capable non-replicated state to a second replicated state manager executing on the second server.

20. A system as recited in claim 19, wherein the migration-capable non-replicated state is transferred using a replicated state manager specific transfer protocol.

21. A method for initializing migrating managed state for a Java based application, comprising the operations of:

sending a request to a second server to start a migrated module, the request being sent from a control module of a first module executing on a first server, wherein the control module passes a schema specification;

creating the migrated module on the second server;

creating a state partitions for the migrated module based on the passed schema specification; and

recovering a managed state for the migrated module from a state server.

22. A method as recited in claim 21, further comprising the operation of initializing the managed state for the migrated module using a replicated state manager executing on the first server.

23. A method as recited in claim 22, wherein the replicated state manager uses a replicated state manager specific protocol to transfer initialization data to the migrated module.

24. A method as recited in claim 21, wherein a replicated state manager creates the state partitions for the migrated module based on the passed schema specification.

25. A method as recited in claim 24, wherein the replicated state manager further creates SMUs for the migrated module.

26. A method as recited in claim 25, further comprising the operation of informing the control module to switch control to the migrated module.