AIDING RESOLUTION OF A TRANSACTION

• US 20110055835A1
• Filed: 07/22/2010
• Published: 03/03/2011
• Est. Priority Date: 08/28/2009
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Willoughby, Philip G., Squibb, Jamie P., Dennis, Paul S., Siddall, Pete, Hobson, Stephen J.
• Granted Patent: US 9,201,684 B2
• Time in Patent Office: Days
• US Class Current: 718/101
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/1474 in transactions G06F16/20 takes precedence
• CPC Class Codes: G06F 16/2343 Locking methods, e.g. distributed locking or locking implementation details
• CPC Class Codes: G06F 16/2379 Updates performed during online database operations; commit processing
• CPC Class Codes: G06F 9/466 Transaction processing
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

A method for aiding resolution of a transaction for use with a transactional processing system comprising a transaction coordinator and a plurality of grouped and inter-connected resource managers, the method comprising the steps of: in response to a communications failure between the transaction coordinator and a first resource manager causing a transaction to have an in-doubt state, connecting, by the transaction coordinator, to a second resource manager; in response to the connecting step, sending by the transaction coordinator to the second resource manager, a resolve request comprising a resolution for the in-doubt transaction; in response to the resolve request, obtaining at the first resource manager, by the second resource manager, a lock to data associated with the in-doubt transaction; and in response to the obtaining step, determining, by the second resource manager, whether the transaction is associated with the first resource manager.

Claims

1-15. -15. (canceled)

16. A computer implemented method for aiding resolution of a transaction for use with a transactional processing system, comprising a transaction coordinator and a plurality of grouped and inter-connected resource managers, the computer implemented method comprising:

in response to a communications failure between the transaction coordinator and a first resource manager causing a transaction to have an in-doubt state, connecting, by the transaction coordinator, to a second resource manager;

in response to connecting, sending by the transaction coordinator to the second resource manager, a resolve request comprising a resolution for an in-doubt transaction;

in response to the resolve request, obtaining at the first resource manager, by the second resource manager, a lock to data associated with the in-doubt transaction; and

in response to obtaining, determining, by the second resource manager, whether the transaction is associated with the first resource manager.

17. The computer implemented method of claim 16, further comprising:

in response to determining that the transaction is associated with the first resource manager, determining, by the second resource manager, whether the transaction is in doubt.

18. The computer implemented method of claim 16, wherein the lock is exclusive.

19. The computer implemented method of claim 16, wherein the lock is shared.

20. The computer implemented method of claim 17, further comprising:

in response to determining that the transaction is not in doubt, releasing, by the second resource manager, the lock.

21. The computer implemented method of claim 17, further comprising:

in response to determining that the transaction is in doubt, writing, by the second resource manager, the resolution to a log of the first resource manager.

22. The computer implemented method of claim 21, further comprising:

obtaining, at the first resource manager prior to writing, by the second resource manager, an exclusive lock to the log of the first resource manager.

23. The computer implemented method of claim 22, further comprising:

in response to writing the resolution to the log of the first resource manager, releasing, by the second resource manager, the lock.

24. The computer implemented method of claim 21, further comprising:

checking a size associated with a log associated with the first resource manager prior to checking whether the transaction is associated with the first resource manager.

25. The computer implemented method of claim 24, further comprising:

re-checking the size to determine whether the size has changed; and

in response to determining that the size has not changed and that the transaction is in doubt, writing, by the second resource manager, the resolution to the log of the first resource manager.

26. The computer implemented method of claim 25, wherein the size is associated with a subset of the log.

27. The computer implemented method of claim 26, further comprising:

in response to sending, determining, by the second resource manager, whether the transaction is associated with at least one of the second resource manager and another resource manager in the group.

28. The computer implemented method of claim 27, further comprising:

transmitting data associated with the in-doubt transaction to a transaction coordinator.

29. An apparatus for aiding resolution of a transaction for use with a transactional processing system, comprising a transaction coordinator and a plurality of grouped and inter-connected resource managers, the apparatus comprising:

means, responsive to a communications failure between the transaction coordinator and a first resource manager causing a transaction to have an in-doubt state, for connecting the transaction coordinator to a second resource manager;

means, responsive to the connecting means, for sending, by the transaction coordinator a resolve request comprising a resolution for an in-doubt transaction to the second resource manager;

means, responsive to the sending means, for obtaining, at the first resource manager, a lock to data associated with the in-doubt transaction, wherein obtaining is by the second resource manager; and

means, responsive to the obtaining means, for causing the second resource manager to determine whether the transaction is associated with the first resource manager.