Research issues in real-time database systems

Cataloged from PDF version of article.Today's real-time systems are characterized by managing large volumes of data. Efficient database management algorithms for accessing and manipulating data are required to satisfy timing constraints of supported applications. Real-time database systems involve a new research area investigating possible ways of applying database systems technology to real-time systems. Management of real-time information through a database system requires the integration of concepts from both real-time systems and database systems. Some new criteria need to be developed to involve timing constraints of real-time applications in many database systems design issues, such as transaction/query processing, data buffering, CPU, and IO scheduling. In this paper, a basic understanding of the issues in real-time database systems is provided and the research efforts in this area are introduced. Different approaches to various problems of real-time database systems are briefly described, and possible future research directions are discussed

Real-time scheduling of transactions in multicore systems

International audienceTransactional memory has attracted much interest for multicore systems as it eases programming and avoids the problems of lock-based methods. However, introducing real-time scheduling of transactions in multicore systems is an open problem. Existing solutions for real-time scheduling consider either tasks in multiprocessor systems or transactions in database systems. In this paper, we show that these solutions are not suitable for multicore systems. And we discuss the main challenges to introduce real-time scheduling within transactional memory in multicore systems

Comparing two-phase locking and optimistic concurrency control protocols in multiprocessor real-time databases

Previous studies (Haritsa et al., 1990) have shown that optimistic concurrency control (OCC) generally performs better than lock-based protocols in disk-based real-time database systems (RTDBS). We compare the two concurrency control protocols in both disk-based and memory-resident multiprocessor RTDBS. Based on their performance characteristics, a new lock-based protocol, called two phase locking-lock write all (2PL-LW), is proposed. The results of our performance evaluation experiments show that different characteristics of the two environments indeed have great impact on the protocols' performance. We identify such system characteristics and show that our new lock-based protocols, 2PL-LW, is better than OCC in meeting transaction deadlines in both disk-based and memory-resident RTDBS.published_or_final_versio

A Comprehensive Concurrency Control Technique for Real-Time Database System

Real-time database must maintain the Temporal Consistency of the data which cannot be achieved with the conventional concurrency control techniques as they focus only on the consistency of the data. Different protocols exhibit good performance on different situations. But a single technique is inadequate to meet the demand of real-time database. To improve the concurrency control technique for real-time transactions, this paper will present a comprehensive technique that coordinates multi-version, OCC Sacrifice, Speculative Concurrency Control and 2PL-HP protocols. The presented technique uses best suited protocol based on the contention of transactions. Thus it can significantly improve the concurrency of transactions as well as increase the number of transactions

An Evaluation of Network Access Protocols for Distributed Real-time Database Systems

Cataloged from PDF version of article.The results of a considerable number of works addressing various features of real-time database systems (RTDBSs) have recently appeared in the literature. An issue that has not received much attention yet is the performance of the communication network configuration in a distributed RTDBS. In this article, we examine the impact of underlying network architecture on the performance of a distributed RTDBS. In particular, we evaluate the real-time performance of distributed transactions in terms of the fraction of satisfied deadlines under various network access strategies. We also critically examine the common assumption of constant network delay for each communication message exchanged in a distributed RTDBS. (C) 1997 by Elsevier Science Inc

Analysis of concurrency control protocols for real-time database systems

Cataloged from PDF version of article.This paper provides an approximate analytic solution method for evaluating the performance of concurrency control protocols developed for real-time database systems (RTDBSs). Transactions processed in a RTDBS are associated with timing constraints typically in the form of deadlines. The primary consideration in developing a RTDBS concurrency control protocol is the fact that satisfaction of the timing constraints of transactions is as important as maintaining the consistency of the underlying database. The proposed solution method provides the evaluation of the performance of concurrency control protocols in terms of the satisfaction rate of timing constraints. As a case study, a RTDBS concurrency control protocol, called High Priority, is analyzed using the proposed method. The accuracy of the performance results obtained is ascertained via simulation. The solution method is also used to investigate the real-time performance benefits of the High Priority over the ordinary Two-Phase Locking. © 1998 Elsevier Science Inc. All rights reserved

Research issues in real-time database systems. Survey paper

Today's real-time systems are characterized by managing large volumes of data. Efficient database management algorithms for accessing and manipulating data are required to satisfy timing constraints of supported applications. Real-time database systems involve a new research area investigating possible ways of applying database systems technology to real-time systems. Management of real-time information through a database system requires the integration of concepts from both real-time systems and database systems. Some new criteria need to be developed to involve timing constraints of real-time applications in many database systems design issues, such as transaction/query processing, data buffering, CPU, and IO scheduling. In this paper, a basic understanding of the issues in real-time database systems is provided and the research efforts in this area are introduced. Different approaches to various problems of real-time database systems are briefly described, and possible future research directions are discussed. © 1995