Active Transactions
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Active transactions (in Collaborative Virtual Environments) is a consistency model focused on the strength of the data consistency. It was developed by Jan Pečiva at Brno University of Technology in 2006.
Collaborative/networked virtual environments (CVE), such as multiplayer games and distributed simulations, share the virtual environment data over network. The sharing is usually realized by the data replication among the computers and some data consistency model. The consistency model deeply influences performance of the whole system, and also complexity of its programming model. The architects of multiprocessor systems strived to design such consistency models that are as close as possible to sequential consistency that programmers of single processor systems are familiar with. However, sequential consistency realized on multiprocessor system usually degrades unacceptably the performance of the system. Weakening of the consistency increases the system performance, but it is going hand-to-hand with increasing complexity of the programming model. Active transactions are trying to keep high performance while keeping simple programming model close to the sequential consistency, thus reducing the complexity of the application and associated programming and maintaining resources.
Theoretical foundations of active transactions are based on active replication from distributed systems and transaction concept from database systems. Both concepts were modified and adapted to reach the performance requirements of CVE systems.
To prove Active transactions usability and easiness of usage, they were made a part of Open Inventor library as an extension. Then, the Open Inventor scene graph is automatically shared without a need to change application code. Several applications were developed using the library.
[edit] Research papers
- Pečiva, J. 2007. Active Transactions in Collaborative Virtual Environments. PhD Thesis, Brno, Czech Republic.
- Pečiva, J. 2006. Active transaction approach for collaborative virtual environments. In Proceedings of the 2006 ACM international Conference on Virtual Reality Continuum and Its Applications (Hong Kong, China). VRCIA '06. ACM Press, New York, NY, 171-178. DOI= http://doi.acm.org/10.1145/1128923.1128950
- Pečiva, J. 2005. Omnipresent Collaborative Virtual Environments for Open Inventor Applications. Springer LNCS, Volume 3814, Nov 2005, Pages 272 - 276. DOI=http://dx.doi.org/10.1007/11590323_33
