EDRC

Author(s):  
Sarvesh Pandey ◽  
Udai Shanker

Advancing the distributed real-time database systems (DRTDBS) performance requires critical consideration of the reasons for data inaccessibility (i.e., predictability and consistency, scheduling and conflict resolution schemes, and commit process). Traditionally, execute-commit conflict is handled through the two-phase commit protocol to ensure the consistency of the database by blocking an incoming cohort intending to access the data item(s) already locked by other prepared cohort. Such blocking makes the transaction execution time of incoming cohort unpredictable due to unbounded waiting time. This chapter proposes an early data lending-based real-time commit (EDRC) protocol that increases data accessibility by providing the means to start the lending process early. Furthermore, lender is permitted to lend its uncommitted data items just after the completion of data processing task. The EDRC protocol outperforms state-of-the-art distributed commit protocols particularly PROMPT, 2SC, and SWIFT under all load conditions.

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.


Author(s):  
Fadia A. Elbagir ◽  
◽  
Ahmed Khalid ◽  
Khalid Khanfar

2020 ◽  
Vol 13 (4) ◽  
pp. 758-770 ◽  
Author(s):  
Prakash Kumar Singh ◽  
Udai Shanker

Background: Today's widely used small and portable mobile database technologies have geared toward the mobile distributed real-time database systems (MDRTDBS).Various real time applications like mobile devices, missile systems, navigation control systems, satellites and many others are some examples of MDRTDBS. In the new era of technology, a large domain of applications are based on MDRTDBS, meanwhile different intrinsic limitation like disconnection and mobility typically effect on its correct execution. Mobile distributed real-time systems have different wireless constrained such like energy, processing capacity, memory storage facilities and variable network communication channels. In last few years, different applications run on different mobile nodes needed a suitable transaction mechanism to complete their service without failing its deadline. In recent years researchers focused on MDRTDBS, to develop a suitable concurrency control, commit control method. Replication, check pointing, security, caching and query processing are some other hot research topics in the field of MDRTDBS. Objective: it is needed to maintain data consistency and correct results in mobile distributed real time database system. In our review we have identified key issues which might be considered for development of various transaction executing protocols. We have Introduce a taxonomy of different CC, commit, replication and security issues, which could be advantageous for design, and development of transaction protocols. Method: In the review we have discussed various concurrency, commit, replication methods. Apart from these we have discussed various check pointing, caching and query techniques which is developed in database system. A comparison among various concurrency and commit protocols has been done in the review. The role of different key methods which can affect and help the transaction execution in wireless environment is discussed separately in the paper. Results: Analytical results are not mentioned in the review paper. However the role and affect on the transaction execution are mentioned clearly. Issues and their advantages of different concurrency and commit protocols are mentioned. Results: Analytical results are not mentioned in the review paper. However the role and affect on the transaction execution are mentioned clearly. Issues and their advantages of different concurrency and commit protocols are mentioned. Conclusion: It is found that transaction processing is still a challenging area of research. A number of issues has been discussed and reviewed various approaches to control concurrency control and atomicity methods. We have presented a detailed survey and classification of various issues based on commit, concurrency, and replication methods for MTDRTDBS. However, in the paper different security, caching and query processing and check pointing issues has been also discussed which should be considered for future work. Database researchers have needed to integrate these issues with their work and develop a suitable protocol.


2006 ◽  
Author(s):  
Sang H. Son ◽  
Rasikan David ◽  
Bhavani Thuraisingham
Keyword(s):  

1997 ◽  
Vol 26 (2) ◽  
pp. 462-473 ◽  
Author(s):  
Binto George ◽  
Jayant Haritsa

2016 ◽  
Vol 27 (5) ◽  
pp. 1497-1510 ◽  
Author(s):  
Mohammad Salehi ◽  
Alireza Ejlali ◽  
Bashir M. Al-Hashimi

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