Method, system, and program for managing locks and transactions

• US 20040220933A1
• Filed: 05/01/2003
• Published: 11/04/2004
• Est. Priority Date: 05/01/2003
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Walker, Michael Leo
• Granted Patent: US 7,496,574 B2
• Time in Patent Office: Days
• US Class Current: 707/8
• CPC Class Codes: G06F 9/466 Transaction processing
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

Disclosed is a method, system, and program for locking. A request is received with a first operation identifier to lock a first resource. The first resource is locked with the first operation identifier. It is determined whether a second resource should be locked with the first operation identifier or with a second operation identifier based on whether an operation to be performed for the request may complete after the request is processed.

Additionally disclosed is a method, system, and program for locking in which a request is received to lock a resource with a first operation identifier. It is determined whether the resource is locked with the first operation identifier. If it is determined that the resource is locked with the first operation identifier, the request receives a response with an indication that the resource is locked with the first operation identifier. If it is determined that the resource is locked with a second operation identifier, the lock request is denied.

Further disclosed is a method, system, and program for deadlock management. An indication of refusal of a lock request with a first operation identifier is received for a resource that is locked with a second operation identifier. The lock request is placed in a queue with a lock queue timeout period. The lock request is reissued if the lock request reaches a position of the queue from which the lock request may be processed within the lock queue timeout period.

Claims

1. A method for locking, comprising:

receiving a request with a first operation identifier to lock a first resource;

locking the first resource with the first operation identifier; and

determining whether a second resource should be locked with the first operation identifier or with a second operation identifier based on whether an operation to be performed for the request may complete after the request is processed.

2. The method of claim 1, further comprising:

determining that the second resource should be locked with the first operation identifier; and

locking the second resource with the first operation identifier.

3. The method of claim 2, further comprising:

determining that the second resource should be locked with a second operation identifier;

obtaining the second operation identifier; and

locking the second resource with the second operation identifier.

4. A system for locking, comprising:

a processor;

a computer readable medium accessible to the processor; and

program logic including code capable of causing the processor to perform;

(i) receiving a request with a first operation identifier to lock a first resource;

(ii) locking the first resource with the first operation identifier; and

(iii) determining whether a second resource should be locked with the first operation identifier or with a second operation identifier based on whether an operation to be performed for the request may complete after the request is processed.

5. The system of claim 4, wherein the code is capable of causing the processor to further perform:

determining that the second resource should be locked with the first operation identifier; and

locking the second resource with the first operation identifier.

6. The system of claim 5, wherein the code is capable of causing the processor to further perform:

determining that the second resource should be locked with a second operation identifier;

obtaining the second operation identifier; and

locking the second resource with the second operation identifier.

7. An article of manufacture including program logic for locking, wherein the program logic causes operations to be performed, the operations comprising:

receiving a request with a first operation identifier to lock a first resource;

locking the first resource with the first operation identifier; and

determining whether a second resource should be locked with the first operation identifier or with a second operation identifier based on whether an operation to be performed for the request may complete after the request is processed.

8. The article of manufacture of claim 7, the operations further comprising:

determining that the second resource should be locked with the first operation identifier; and

locking the second resource with the first operation identifier.

9. The article of manufacture of claim 8, the operations further comprising:

determining that the second resource should be locked with a second operation identifier;

obtaining the second operation identifier; and

locking the second resource with the second operation identifier.

10. A system for locking, comprising:

an agent;

a first resource controlled by the agent;

a second resource not controlled by the agent;

means for receiving a request with a first operation identifier to lock the first resource;

means for locking the first resource with the first operation identifier; and

means for determining whether the second resource should be locked with the first operation identifier or with a second operation identifier based on whether an operation to be performed for the request may complete after the request is processed.

11. A method for locking, comprising:

receiving a request to lock a resource with a first operation identifier;

determining whether the resource is locked with the first operation identifier;

if it is determined that the resource is locked with the first operation identifier, responding to the request with an indication that the resource is locked with the first operation identifier; and

if it is determined that the resource is locked with a second operation identifier, denying the lock request.

12. The method of claim 11, wherein determining whether the resource is locked with the first operation identifier further comprises:

matching the first operation identifier against an operation identifier used to lock the resource.

13. A system for locking, comprising:

a processor;

a computer readable medium accessible to the processor; and

program logic including code capable of causing the processor to perform;

(i) receiving a request to lock a resource with a first operation identifier;

(ii) determining whether the resource is locked with the first operation identifier;

(iii) if it is determined that the resource is locked with the first operation identifier, responding to the request with an indication that the resource is locked with the first operation identifier; and

(iv) if it is determined that the resource is locked with a second operation identifier, denying the lock request.

14. The system of claim 13, wherein in determining whether the resource is locked with the first operation identifier, the code is capable of causing the processor to further perform:

matching the first operation identifier against an operation identifier used to lock the resource.

15. An article of manufacture including program logic for locking, wherein the program logic causes operations to be performed, the operations comprising:

receiving a request to lock a resource with a first operation identifier;

determining whether the resource is locked with the first operation identifier;

if it is determined that the resource is locked with the first operation identifier, responding to the request with an indication that the resource is locked with the first operation identifier; and

if it is determined that the resource is locked with a second operation identifier, denying the lock request.

16. The article of manufacture of claim 15, wherein for determining whether the resource is locked with the first operation identifier, the operations further comprise:

matching the first operation identifier against an operation identifier used to lock the resource.

17. A system for locking, comprising:

means for receiving a request to lock a resource with a first operation identifier;

means for determining whether the resource is locked with the first operation identifier by matching the first operation identifier against an operation identifier used to lock the resource;

means for, if it is determined that the resource is locked with the first operation identifier, responding to the request with an indication that the resource is locked with the first operation identifier; and

means for, if it is determined that the resource is locked with a second operation identifier, denying the lock request.

18. A method for deadlock management comprising:

receiving an indication of refusal of a lock request with a first operation identifier for a resource that is locked with a second operation identifier;

placing the lock request in a queue with a lock queue timeout period; and

reissuing the lock request if the lock request reaches a position of the queue from which the lock request may be processed within the lock queue timeout period.

19. The method of claim 18, further comprising:

if the lock request is not granted within the lock queue timeout period, denying the lock request.

20. A system for deadlock management, comprising:

a processor;

a computer readable medium accessible to the processor; and

program logic including code capable of causing the processor to perform;

(i) receiving an indication of refusal of a lock request with a first operation identifier for a resource that is locked with a second operation identifier;

(ii) placing the lock request in a queue with a lock queue timeout period; and

(iii) reissuing the lock request if the lock request reaches a position of the queue from which the lock request may be processed within the lock queue timeout period.

21. The system of claim 20, wherein the code is capable of causing the processor to further perform:

if the lock request is not granted within the lock queue timeout period, denying the lock request.

22. An article of manufacture including program logic for deadlock management, wherein the program logic causes operations to be performed, the operations comprising:

receiving an indication of refusal of a lock request with a first operation identifier for a resource that is locked with a second operation identifier;

placing the lock request in a queue with a lock queue timeout period; and

reissuing the lock request if the lock request reaches a position of the queue from which the lock request may be processed within the lock queue timeout period.

23. The article of manufacture of claim 22, the operations further comprising:

if the lock request is not granted within the lock queue timeout period, denying the lock request.

24. A system for deadlock management, comprising:

means for receiving an indication of refusal of a lock request with a first operation identifier for a resource that is locked with a second operation identifier;

means for placing the lock request in a queue with a lock queue timeout period;

means for, reissuing the lock request if the lock request reaches a position of the queue from which the lock request may be processed within the lock queue timeout period.