Failover protection from a failed worker node in a shared memory system

• US 20060143328A1
• Filed: 12/28/2004
• Published: 06/29/2006
• Est. Priority Date: 12/28/2004
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Kilian, Frank, Stanev, Georgi, Galchev, Galin, Luik, Oliver, Fleischer, Christian
• Granted Patent: US 8,140,678 B2
• Time in Patent Office: Days
• US Class Current: 710/19
• CPC Class Codes: G06F 9/5027 the resource being a machine, e.g. CPUs, Servers, Terminals
• CPC Class Codes: G06F 9/505 considering the load

Abstract

A method is described that involves entering a notification of a request into a queue that supplies request notifications to a first worker node amongst a plurality of worker nodes. The first worker node is targeted to process the request. In response to the first worker node failing before the notification could be serviced from the first queue, the notification is moved from the first queue to a second queue that supplies request notifications to a second worker node amongst the plurality of worker nodes. After servicing the notification from the second queue, the request is transferred to the second worker node. A response to the request is then generated with the second worker node.

Claims

1. A method to handle a session between computing systems, comprising:

entering a notification of a request into a queue that supplies request notifications to a first worker node amongst a plurality of worker nodes, said first worker node targeted to process said request;

in response to said first worker node failing before said notification could be serviced from said first queue, moving said notification from said first queue to a second queue that supplies request notifications to a second worker node amongst said plurality of worker nodes;

after servicing said notification from said second queue, transferring said request to said second worker node; and

,

generating a response to said request with said second worker node.

2. The method of claim 1 wherein said method further comprises, before said failing, incrementing a counter maintained for said session.

3. The method of claim 2 wherein said method further comprises, after said generating, said second worker node acting to decrement said counter.

4. The method of claim 2 wherein said method further comprises, after said incrementing and before said servicing, decrementing said counter to indicate said notification has been removed from said first queue.

5. The method of claim 4 wherein said method further comprises, after said decrementing and before said servicing, incrementing said counter to indicate said notification has been entered into said second queue.

6. The method of claim 1 wherein said method further comprises entering said request into a shared memory prior to said failing, and wherein, said transferring comprises transferring said request from said shared memory to said second worker node.

7. The method of claim 6 wherein said method further comprises removing said response from said shared memory and sending it to said client.

8. The method of claim 1 further comprising, after said failing, determining that said notification is to be sent to said second worker node with a load balancing algorithm.

9. The method of claim 1 wherein said second worker node reads session information for said session from a shared closure shared memory, said session information being in the form of a shared closure.

10. The method of claim 1 wherein said notification contains a pointer to said request data.

12. The article of manufacture of claim 1 wherein said method further comprises, before said failing, incrementing a counter maintained for said session.

13. The article of manufacture of claim 2 wherein said method further comprises, after said generating, said second worker node acting to decrement said counter.

14. The article of manufacture of claim 2 wherein said method further comprises, after said incrementing and before said servicing, decrementing said counter to indicate said notification has been removed from said first queue.

15. The article of manufacture of claim 4 wherein said method further comprises, after said decrementing and before said servicing, incrementing said counter to indicate said notification has been entered into said second queue.

16. The article of manufacture of claim 1 wherein said method further comprises entering said request into a shared memory prior to said failing, and wherein, said transferring comprises transferring said request from said shared memory to said second worker node.

17. The article of manufacture of claim 6 wherein said method further comprises removing said response from said shared memory and sending it to said client.

18. The article of manufacture of claim 1 further comprising, after said failing, determining that said notification is to be sent to said second worker node with a load balancing algorithm.

19. The article of manufacture of claim 1 wherein said second worker node reads session information for said session from a shared closure shared memory, said session information being in the form of a shared closure.

20. The article of manufacture of claim 1 wherein said notification contains a pointer to said request data.

11. An article of manufacture including program code which, when executed by a machine, causes the machine to perform a method to handle a session between computing systems, the method comprising:

entering a notification of a request into a queue that supplies request notifications to a first worker node amongst a plurality of worker nodes, said first worker node targeted to process said request;

in response to said first worker node failing before said notification could be serviced from said first queue, moving said notification from said first queue to a second queue that supplies request notifications to a second worker node amongst said plurality of worker nodes;

after servicing said notification from said second queue, transferring said request to said second worker node; and

,

generating a response to said request with said second worker node.

21. A computing system comprising machines, said machines comprising a virtual machine and a processor, said computing system also comprising instructions disposed on a computer readable medium, said instructions capable of being executed by one of said machines to perform a method to handle a session between said computing system and another computer system, said method comprising:

entering a notification of a request into a queue that supplies request notifications to a first worker node amongst a plurality of worker nodes, said first worker node targeted to process said request;

in response to said first worker node failing before said notification could be serviced from said first queue, moving said notification from said first queue to a second queue that supplies request notifications to a second worker node amongst said plurality of worker nodes;

after servicing said notification from said second queue, transferring said request to said second worker node; and

,

generating a response to said request with said second worker node.

22. The computing system of claim 21 wherein said method further comprises, before said failing, incrementing a counter maintained for said session.

23. The computing system of claim 22 wherein said method further comprises, after said generating, said second worker node acting to decrement said counter.

24. The computing system of claim 22 wherein said method further comprises, after said incrementing and before said servicing, decrementing said counter to indicate said notification has been removed from said first queue.

25. The computing system of claim 24 wherein said method further comprises, after said decrementing and before said servicing, incrementing said counter to indicate said notification has been entered into said second queue.

26. The computing system of claim 21 wherein said method further comprises entering said request into a shared memory prior to said failing, and wherein, said transferring comprises transferring said request from said shared memory to said second worker node.

27. The computing system of claim 26 wherein said method further comprises removing said response from said shared memory and sending it to said client.

28. The computing system of claim 21 further comprising, after said failing, determining that said notification is to be sent to said second worker node with a load balancing algorithm.

29. The computing system of claim 21 wherein said second worker node reads session information for said session from a shared closure shared memory, said session information being in the form of a shared closure.

30. The computing system of claim 21 wherein said notification contains a pointer to said request data.