High performance distributed real-time commit protocol

In a distributed real-time database system, the only way to ensure transaction atomicity is to investigate and develop a real-time atomic commit protocol. This paper presents the model of distributed real-time transaction and analyses all kinds of dependencies because of data conflicts access. Based on this model, we propose an optimistic real-time commit protocol, double space commit (2SC), which is specifically designed for the high-performance distributed real-time transaction. 2SC allows a non-healthy transaction to lend its held data to the transactions in its commit dependency set. When the prepared transaction aborts, only the transactions in its abort dependency set are aborted while the transactions in its commit dependency set will execute as normal. The two properties of 2SC can reduce the data inaccessibility and the priority inversion that is inherent in distributed real-time commit processing. Extensive simulation experiments have been performed to compare the performance of the 2SC with that of other protocols such as the base protocol, the permits reading of modified prepared-data for timeliness [IEEE Transactions on Parallel and Distributed Systems 11 (2) (2000) 160-181] and the deadline-driven conflict resolution [The Computer Journal 42 (8) (1999) 674-692]. The simulation results show that 2SC has the best performance. Furthermore, it is easy to incorporate in current concurrency control protocols. (C) 2002 Elsevier Inc. All rights reserved.