Enhancer-A Time Commit Protocol

Abstract-This paper contains content with the investigating the performance implications of providing transaction atomicity for a deadline real time applications operating on distributed data. Considering all the commit protocols and discussing all phases of the commit protocols and examine their working model over different aspects of distributed database. Implementing distributed real time database system(DRTDBS) content which must be design on all level of database architecture to support timely execution of request. The enormous progress in applications of distributed database systems necessitates formulation of an efficient atomic commitment protocol. The efficiency of these protocols is vital when higher transaction throughput is to be supported. The existing blocking commit protocols affect over the capacity of system resources, which worsens in distributed database system Many existing real time commit protocols try to enhance system performance by allowing a committing participant to share its data to an executing participant, thus it reduces data inaccessibility

The design of robust protocols for distributed real-time systems

Modern distributed control systems comprise of a set of processors which are interconnected using a suitable communication network. For use in real-time control environments, such systems must be deterministic and generate specified responses within critical timing constraints. Also, they should be sufficiently robust to survive predictable events such as communication or processor faults. This thesis considers the problem of coordinating and synchronizing a distributed real-time control system under normal and abnormal conditions. Distributed control systems need to periodically coordinate the actions of several autonomous sites. Often the type of coordination required is the all or nothing property of an atomic action. Atomic commit protocols have been used to achieve this atomicity in distributed database systems which are not subject to deadlines. This thesis addresses the problem of applying time constraints to atomic commit protocols so that decisions can be made within a deadline. A modified protocol is proposed which is suitable for real-time applications. The thesis also addresses the problem of ensuring that atomicity is provided even if processor or communication failures occur. Previous work has considered the design of atomic commit protocols for use in non time critical distributed database systems. However, in a distributed real-time control system a fault must not allow stringent timing constraints to be violated. This thesis proposes commit protocols using synchronous communications which can be made resilient to a single processor or communication failure and still satisfy deadlines. Previous formal models used to design commit protocols have had adequate state coverability but have omitted timing properties. They also assumed that sites communicated asynchronously and omitted the communications from the model. Timed Petri nets are used in this thesis to specify and design the proposed protocols which are analysed for consistency and timeliness. Also the communication system is mcxielled within the Petri net specifications so that communication failures can be included in the analysis. Analysis of the Timed Petri net and the associated reachability tree is used to show the proposed protocols always terminate consistently and satisfy timing constraints. Finally the applications of this work are described. Two different types of applications are considered, real-time databases and real-time control systems. It is shown that it may be advantageous to use synchronous communications in distributed database systems, especially if predictable response times are required. Emphasis is given to the application of the developed commit protocols to real-time control systems. Using the same analysis techniques as those used for the design of the protocols it can be shown that the overall system performs as expected both functionally and temporally

Modified (2PVCP) for Better Transaction Processing in Secure Cloud

Entities in distributed transactional database that published over cloud servers, collaborate to make evidence of ownership, this evidence are warranted by groups of legalized credential. This evidence and credential may be estimated and gathered over extended time period under the risk of having the essential ownership policies or the user that use this credential may use it out of these policies, for that becomes policy based ownership systems to make unsafe judgment that threaten sensitive resources. In this paper, the highlight is for the criticalness of this risk or problem, and then we declare the concept of trusted transaction when dealing with evidence of ownership. Accordingly the paper suggests increasingly stringent level of policy consistency constraints, and provides different implementation approximation to warranty the trustworthiness of transaction executing on cloud server. So we propose a Tow Phase Validation Commit Protocol as solution that modifies Tow Phase Validation Commit Protocols. At the last, we analyzed the different implementations by using both analytical estimation of the overheads and emulation to lead the judgment maker to decide which scheme to use. We built a prototype application that demonstrates the proof of concept. The empirical results revealed that the mechanisms pertaining to distributed transactions can be used in the real world cloud applications. DOI: 10.17762/ijritcc2321-8169.150711

Speculative Concurrency Control for Real-Time Databases

In this paper, we propose a new class of Concurrency Control Algorithms that is especially suited for real-time database applications. Our approach relies on the use of (potentially) redundant computations to ensure that serializable schedules are found and executed as early as possible, thus, increasing the chances of a timely commitment of transactions with strict timing constraints. Due to its nature, we term our concurrency control algorithms Speculative. The aforementioned description encompasses many algorithms that we call collectively Speculative Concurrency Control (SCC) algorithms. SCC algorithms combine the advantages of both Pessimistic and Optimistic Concurrency Control (PCC and OCC) algorithms, while avoiding their disadvantages. On the one hand, SCC resembles PCC in that conflicts are detected as early as possible, thus making alternative schedules available in a timely fashion in case they are needed. On the other hand, SCC resembles OCC in that it allows conflicting transactions to proceed concurrently, thus avoiding unnecessary delays that may jeopardize their timely commitment