Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
1998-10-05
2002-03-26
Corrielus, Jean M. (Department: 2172)
Data processing: database and file management or data structures
Database design
Data structure types
C707S793000, C707S793000, C714S016000
Reexamination Certificate
active
06363401
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention.
The invention relates in general to computer systems, and more particularly, to an enhanced two-phase commit protocol for distributed data processing environments.
2. Description of Related Art.
In distributed data processing environments, two-phase commit protocols are used to coordinate transactions against one or more data sources. Transactions must be coordinated with other data sources in the network or system to ensure that the data sources have current information.
These data sources may include multiple databases distributed at several locations. In one embodiment of a two-phase commit protocol, the system first checks to see if all data sources are available, and, if so, proceeds to complete the transaction. However, if one or more of the data sources are unavailable or unable to complete the transaction, the transaction is canceled or “undone” until the data source (also known as a participant) is able to complete the transaction, or is queued until all participants are available to complete the transaction. The two-phase commit protocol is necessary for data environments that require high degrees of accuracy across large numbers of distributed computing systems, e.g., banking systems, credit card verification systems, databases for vital statistics, etc.
Although the two-phase commit protocol is useful to ensure data integrity, the limitation of requiring all participants to be able to process the transaction makes the two-phase commit protocol's usefulness limited. Further, since there are many times that a data source or other participant may be unable to accept or process the transaction due to hardware or software malfunctions, preventative maintenance, system reconfigurations, etc., the two-phase commit protocol has even less usefulness.
It can be seen, then, that there is a need in the art for a two-phase commit protocol that can be used when one or more participants are unable to process the transaction. It can also be seen, then, that there is a need in the art for a two-phase commit protocol that will allow those participants unable to participate in the initial database update to be updated once the participant is again able to participate in the transaction process.
SUMMARY OF THE INVENTION
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a method, apparatus, and article of manufacture for performing a two-phase commit protocol for a transaction in a system having a plurality of data sources. An availability status is verified for all of the data sources, and the two-phase commit protocol for the transaction is completed (committed) for those data sources that are available, while the transaction is logged for data sources that are unavailable. The approach used in the present invention allows for a wider application of the two-phase commit protocol for networks that require the accuracy and precision that the two-phase commit protocol delivers.
These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and form a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying detailed description, in which there is illustrated and described specific examples of a method, apparatus, and article of manufacture in accordance with the invention.
REFERENCES:
patent: 4412287 (1983-10-01), Braddock, III
patent: 5095421 (1992-03-01), Freund
patent: 5301320 (1994-04-01), McAtee et al.
patent: 5452445 (1995-09-01), Hallmark et al.
patent: 5455952 (1995-10-01), Russell
patent: 5530848 (1996-06-01), Gilbert et al.
patent: 5850507 (1998-12-01), Ngai et al.
patent: 6105147 (2000-08-01), Molloy
patent: 6154849 (2000-11-01), Xia
Reddy et al., “Reducing the blocking in two-phase commit protocol employing backup sites” IEEE catalog No. 98EX122, pp. 406-415, Aug. 20-22, 1998.
Ancilotti et al., “A distributed commit protocol for a multicomputer system” IEEE Transaction, vol. 39, No. 5, pp. 718-724, May 1990.
Ghafoor et al., “An efficient communication structure for distributed commit protocols”, IEEE journal, vol. 7, No. 3, pp. 375-389, Apr. 1989.
Pui Ng, “A commit protocol for checkpointing transactions”, Reliable distributed systems, pp. 22-31, Oct. 10-12, 1988.
Barnhart Devin Lyle
Jorgensen Thomas J.
Lee Jerry C.
Stellwagen, Jr. Richard G.
Yahya Muhammad
Corrielus Jean M.
Gates & Cooper
NCR Corporation
LandOfFree
Enhanced two-phase commit protocol does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Enhanced two-phase commit protocol, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Enhanced two-phase commit protocol will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2843316