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Guarantee the Quality-of-Service of Control Transactions in real-time database systems

IEEE ACCESS 2020年 8卷 110511-110522页

作者： Deng, Chenggang Li, Guohui Zhou, Quan Li, Jianjun Huazhong Univ Sci & Technol Dept Comp Sci & Technol Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Dept Software Engn Wuhan 430074 Peoples R China

Temporal consistency analysis is an important problem in real-time database systems (RTDBSs). Most of existing works on hybrid transaction co-scheduling focus on exploring effective deadline and period assignment methods which can guarantee the temporal consistency of data objects and the schedulability of transactions. To the best of our knowledge, all existing researches have not yet invested sufficient efforts on guaranteeing the Quality of Service (QoS) of control transactions and allow control transactions finish their execution after the data obtained by these control transactions expire. In this paper, we define a new problem of how to schedule a hybrid transaction set under the guarantee on QoS of control transactions. Two deadline and period assignment methods for addressing the defined problem are proposed in this work. Both the proposed methods support the Earliest Deadline First (EDF) scheduling. Extensive experiments are conducted to evaluate the performances of the proposed methods in terms of acceptance ratio, processor workload and efficiency.

关键词： real-time systems Quality of service Cloud computing Task analysis database systems Job shop scheduling Processor scheduling real-time database systems QoS of control transactions hybrid transaction set the EDF scheduling deadline and period assignment

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Co-Scheduling of Hybrid Transactions on Multiprocessor real-time database systems

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IEEE ACCESS 2019年 7卷 109506-109517页

作者： Deng, Chenggang Li, Guohui Zhou, Quan Li, Jianjun Huazhong Univ Sci & Technol Dept Comp Sci & Technol Wuhan 430074 Hubei Peoples R China Huazhong Univ Sci & Technol Dept Software Engn Wuhan 430074 Hubei Peoples R China

Deriving deadlines and periods for update transactions and scheduling hybrid transactions have been recognized as an important issue in real-time database systems. Despite years of research, all existing techniques focus on assigning deadlines and periods for update transactions in uniprocessor systems and, thus, cannot be applied in multiprocessor systems. Two partitioned scheduling methods for hybrid transactions in multiprocessor systems are proposed in this paper, by developing existing scheduling methods for uniprocessor systems to multiprocessor environments. An effective strategy is proposed to improve the efficiencies of the proposed methods, under which the improvement of efficiency is at the price of the acceptance ratio of transaction sets. For addressing the low acceptance ratio of the improvement strategy, we propose a novel scheduling method. A set of experiments is conducted to test the performances of the proposed methods. To the best of our knowledge, this is the first paper for co-scheduling of hybrid transactions on multiprocessor platforms.

关键词： real-time database systems multiprocessor hybrid transactions deadlines and periods co-scheduling

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Adaptive co-scheduling for periodic application and update transactions in real-time database systems

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JOURNAL OF systems AND SOFTWARE 2012年第8期85卷 1729-1743页

作者： Han, Song Lam, Kam-yiu Wang, Jiantao Son, Sang H. Mok, Aloysius K. CityU Hong Kong Dept Comp Sci Hong Kong Hong Kong Peoples R China Univ Texas Austin Dept Comp Sci Austin TX 78712 USA Univ Virginia Dept Comp Sci Charlottesville VA 22903 USA

In this paper, we study the co-scheduling problem of periodic application transactions and update transactions in real-time database systems for surveillance of critical events. To perform the surveillance functions effectively, it is important to meet the deadlines of the application transactions and maintain the quality of the real-time data objects for their executions. Unfortunately, these two goals are conflicting and difficult to be achieved at the same time. To address the co-scheduling problem, we propose a real-time co-scheduling algorithm, called Adaptive Earliest Deadline First Co-Scheduling (AEDF-Co). In AEDF-Co, a dynamic scheduling approach is adopted to adaptively schedule the update and application jobs based on their deadlines. The performance goal of AEDF-Co is to determine a schedule for given sets of periodic application and update transactions such that the deadline constraints of all the application transactions are satisfied and at the same time the quality of data (QoD) of the real-time data objects is maximized. Extensive simulation experiments have been performed to evaluate the performance of AEDF-Co. The results show that by adaptively adjusting the release times of update jobs and scheduling the update and application jobs dynamically based on their urgencies, AEDF-Co is effective in achieving the performance goals and maximizing the overall system performance. (C) 2012 Elsevier Inc. All rights reserved.

关键词： real-time database systems Data freshness real-time co-scheduling Update generation and processing

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Dynamic Load Balancing in real-time Distributed Transaction Processing

Dynamic Load Balancing in Real-Time Distributed Transaction ...

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IEEE 16th International Conference on Computational Science and Engineering (CSE)

作者： Haque, Waqar Toms, Andrew Germuth, Aaron Univ No British Columbia Dept Comp Sci Prince George BC V2L 5P2 Canada

ISBN: (纸本)9781479948970

Transaction processing in distributed environments can lead to load imbalances resulting in performance degradation despite resources being available. This can have adverse consequences in a real-time environment where transactions are expected to complete by their deadlines. We propose a novel load balancing protocol, Earliest Completion Load Balancing (ECLB) that monitors the distribution of system load and network latency in an attempt to dynamically create and maintain an evenly loaded system, even in the case of heterogeneous nodes or heavy load conditions. We have assessed its performance against other load balancing protocols under normal and extreme situations. In scenarios of high load or high latency, ECLB is competitive with protocols that would otherwise be better suited to only one or the other. In heterogeneous environments, ECLB outperforms all other protocols. Among other factors, the completion of transactions before their deadlines depends upon both the network latency and load on each node. Thus, ECLB serves as a versatile load balancing protocol for realistic environments. The results are obtained using various network topologies in a parameterized distributed real-time transaction processing simulator.

关键词： Load Balancing real-time database systems Distributed Transaction Processing

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Using Uppaal for Verification of Priority Assignment in real-time databases

Using Uppaal for Verification of Priority Assignment in Real...

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International Conference on Digital Information Processing and Communications (ICDIPC 2011)

作者： Kot, Martin Tech Univ Ostrava VSB Dept Comp Sci Ctr Appl CybernetFEI Ostrava 70833 Czech Republic

ISBN: (纸本)9783642224096

Model checking, as one area of formal verification, is recently subject of an intensive research. Many verification tools intended to check properties of models of systems were developed, mainly at universities. Many researches are also interested in real-time database management systems (RTDBMS). In this paper we show some possibilities of using a verification tool Uppaal on some variants of priority assignment algorithms used in RTDBMS. We present some possible models of such algorithms expressed as nets of timed automata, which are a. modeling language of Uppaal and then some simulation and verification possibilities of Uppaal on those models.

关键词： real-time database systems priority assignment timed automata model checking verification verification tool Uppaal

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Modeling selected real-time database concurrency control protocols in Uppaal

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INNOVATIONS IN systems AND SOFTWARE ENGINEERING 2009年第2期5卷 129-138页

作者： Kot, Martin Tech Univ Ostrava Ctr Appl Cybernet Dept Comp Sci 17 Listopadu 15 Ostrava 70833 Czech Republic

real-time database management systems (RTDBMS) are recently subject of an intensive research. Model checking algorithms and verification tools are of great concern as well. In this paper, we show some possibilities of using a verification tool Uppaal on some variants of pessimistic and optimistic concurrency control protocols used in real-time database management systems. We present some possible models of such protocols expressed as nets of timed automata, which are a modeling language of Uppaal.

关键词： real-time database systems Pessimistic protocol Optimistic protocol Two-phase-locking timed automata Model checking Verification Verification tool Uppaal

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A Data-Centered Transaction Scheduling Strategy of real-time database in Micro-Satellite Ground Test System

A Data-Centered Transaction Scheduling Strategy of Real-time...

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IEEE International Conference on Mechatronics and Automation

作者： Wu Xian-De Sun Zhao-Wei Xing Ze-Jing Harbin Inst Technol Res Inst Satellite Technol Harbin 150006 Heilongjiang Pr Peoples R China Heilongjiang Univ Sch Math Sci Harbin Peoples R China

ISBN: (纸本)9781424426928

This paper studies a transaction scheduling problem in the micro-satellite ground test system. real-time database system is the fundament in data collection, analysis and processing in the test systems. This paper emphasizes on the problem of the failure to deal with abnormal data timely in real-time database system, which will seriously affect the test system validation. Firstly, a real-time database model is designed against large quantity test data, complex data type and tough real-time demand. Then the Data-Centered Transactions Schedule (DCTS) model and the corresponding priority assignment algorithm are presented. Finally, the efficiency, accuracy and effectiveness of algorithms are validated by using mathematical simulation. Computational results demonstrate the effectiveness of the algorithms.

关键词： Micro-satellite test real-time database systems transactions schedule priority assignment

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The database Design in Ground Test System of Micro-satellite Cluster

The Database Design in Ground Test System of Micro-satellite...

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4th IEEE Conference on Industrial Electronics and Applications

作者： Wu Xian-De Deng Hong Sun Zhao-Wei Harbin Inst Technol Res Inst Satellite Technol Harbin 150006 Peoples R China

ISBN: (纸本)9781424427994

The micro-satellite cluster that integrates micro-satellite techniques, command and control techniques, sensor techniques and wireless communication techniques can cooperate with each other to complete high complex missions, and has become an important research area. This paper systematically describes micro-satellite cluster's characteristics, and then presents distributed testbed to shorten test process, and minimize the development cost. The real-time database systems model of distributed test platform is presented to meet the needs of data collection, distribution, processing and representation finally. The distributed test platform designed in this paper provide open access interface, which support rapid integration and test of micro-satellite cluster, and the real-time database systems can response the test data timely and operatively.

关键词： micro-satellite satellite cluster test platform real-time database systems database model

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The Freeze algorithms for concurrency control in secure real-time database systems

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DATA & KNOWLEDGE ENGINEERING 2003年第1期45卷 101-125页

作者： Park, C Park, S Cheju Natl Univ Dept Comp Educ Jeju Si 690756 South Korea Sogang Univ Dept Comp Sci Mapo Gu Seoul 121742 South Korea

database systems for real-time applications must satisfy timing constraints associated with transactions. Typically, a timing. constraint is expressed in the form of a deadline and is represented as a priority to be used by schedulers. Recently, security has become another important issue in many real-time applications. In many systems, sensitive information is shared by multiple users with different levels of security clearance. As more advanced database systems are being used in applications that need to support timeliness while managing sensitive information, there is an urgent need to develop concurrency control (CC) algorithms in transaction management that satisfy both timing and security requirements. In this paper, we propose two CC algorithms that ensure both security and real-time requirements. The proposed algorithms are primarily based on MV locking. However, in order to satisfy timing constraints and security requirements, a new method, called the Freeze, is proposed. In addition, we show that our algorithms work correctly and they provide a higher degree of concurrency than existing MV algorithms. We present several examples to illustrate the behavior of our algorithms, along with performance comparisons with other algorithms. The simulation results show significant performance improvement of the proposed algorithms. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： multiversion concurrency control multilevel security real-time database systems transaction management

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Strategies for resolving inter-class data conflicts in mixed real-time database systems

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JOURNAL OF systems AND SOFTWARE 2002年第1期61卷 1-14页

作者： Lam, KY Kuo, TW Lee, TSH City Univ Hong Kong Dept Comp Sci Kowloon Hong Kong Peoples R China Natl Taiwan Univ Dept Comp Sci & Informat Engn Taipei 106 Taiwan

Although many efficient concurrency control protocols have been proposed for real-time database systems, they are mainly restricted for systems with a single type of real-time transactions or a mixed set of soft real-time and non-real-time transactions only. Their performance objective usually aims at the minimization of the number of missed deadlines of soft real-time transactions or to guarantee the deadline satisfaction of hard real-time transactions. So far, it is still lack of any good study on the design of concurrency control strategies for mixed real-time database systems (MRTDBS), which consist of both hard and soft real-time transactions, and together with non-real-time transactions. Due to the very different performance requirements of hard and soft real-time transactions, existing real-time concurrency control protocols may not be suitable to MRTDBS. In this paper, we propose strategies for resolving data conflicts between different hypes of transactions in an MRTDBS so that the performance requirements of each individual transaction type can be satisfied. and, at the same time, the overall system performance can be improved. The performance of the proposed strategies is evaluated and compared with a real-time optimistic approach, which has been shown to give a better performance than the lock-based protocols for soft and firm real-time transactions. (C) 2002 Elsevier Science Inc. All rights reserved.

关键词： real-time database systems concurrency control and real-time transaction scheduling

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