A Context-Driven Commit Protocol for Enhancing Transactional Services Performance in Pervasive Environments

Author(s):  
Widad Ettazi ◽  
Hatim Hafiddi ◽  
Mahmoud Nassar

The proposed techniques for wireless environments during the last decade have limited support for dynamically changing environments. Due to its nature, the mobile computing environment is extremely dynamic and subject to rapid and unpredictable changes. Similarly, the characteristics of mobile applications affect their transactional requirements. The challenge is to reflect on solutions offering more flexibility and adaptability. In this article, the contribution was focused mainly on the problem of atomic commit that ensures the atomicity property. The trail of adapting mobile transaction commit protocols to context changes has been explored. This has led to the formalization of a flexible transaction model CATSM that supports adaptable properties and a commit protocol CA-TCP that enables adaptation to application requirements and mobile context in terms of transactional properties and execution cost. An architecture based on the concept of adaptation policy has also been designed for the implementation of the proposed solution.

Author(s):  
Ashish Jain

In a mobile computing environment, a potentially large number of mobile and fixed users may simultaneously access shared data; therefore, there is a need to provide a means to allow concurrent management of transactions. Specific characteristics of mobile environments make traditional transaction management techniques no longer appropriate. This is due the fact that the ACID properties of transactions are not simply followed, in particular the consistency property. Thus, transaction management models adopting weaker form of consistency are needed and these models can now tolerate a limited amount of consistency. In this paper we have proposed (execution framework based on common ground shared by most of mobile transaction models found in the literature and investigate it under different execution strategies. More over, the effects of the fixed host transaction are identified and included in the evaluation The integration between wired and wireless environments confirms that the execution strategy is critical for the performance of a system. Neither MHS nor FHS are optimal in all situations and the performance penalties and wasted wireless resources can be substantial. A combined strategy CHS at least matches the best performance of the FHS and MHS and shows better performance than both in many cases.


2012 ◽  
Vol 2012 ◽  
pp. 1-14
Author(s):  
Daniel J. Buehrer ◽  
Chun-Yao Wang

An atomic commit protocol can cause long-term locking of databases if the coordinator crashes or becomes disconnected from the network. In this paper we describe how to eliminate the coordinator. This decentralized, cooperative atomic commit protocol piggybacks transaction statuses of all transaction participants onto tokens which are passed among the participants. Each participant uses the information in the tokens to make a decision of when to go to the next state of a three-phase commit protocol. Transactions can progress to ensure a uniform agreement on success or failure, even if the network is partitioned or nodes temporarily crash.


Author(s):  
Sebastian Obermeier ◽  
Stefan Bottcher ◽  
Martin Hett ◽  
Panos K. Chrysanthis ◽  
George Samaras

Author(s):  
Udai Shanker ◽  
Abhay N. Singh ◽  
Abhinav Anand ◽  
Saurabh Agrawal

This chapter proposes Shadow Sensitive SWIFT commit protocol for Distributed Real Time Database Systems (DRTDBS), where only abort dependent cohort having deadline beyond a specific value (Tshadow_creation_time) can forks off a replica of itself called a shadow, whenever it borrows dirty value of a data item. The new dependencies Commit-on-Termination external dependency between final commit operations of lender and shadow of its borrower and Begin-on-Abort internal dependency between shadow of borrower and borrower itself are defined. If there is serious problem in commitment of lender, execution of borrower is started with its shadow by sending YES-VOTE message piggy bagged with the new result to its coordinator after aborting it and abort dependency created between lender and borrower due to update-read conflict is reversed to commit dependency between shadow and lender with read-update conflict and commit operation governed by Commit-on-Termination dependency. The performance of Shadow Sensitive SWIFT is compared with shadow PROMPT, SWIFT and DSS-SWIFT commit protocols (Haritsa, Ramamritham, & Gupta, 2000; Shanker, Misra, & Sarje, 2006; Shanker, Misra, Sarje, & Shisondia, 2006) for both main memory resident and disk resident databases with and without communication delay. Simulation results show that the proposed protocol improves the system performance up to 5% as transaction miss percentage.


Sign in / Sign up

Export Citation Format

Share Document