Transactional Information Systems is the long-awaited, comprehensive work from leading scientists in the transaction processing field. Weikum and Vossen begin with a broad look at the role of transactional technology in today's economic and scientific endeavors, then delve into critical issues faced by all practitioners, presenting today's most effective techniques for controlling concurrent access by multiple clients, recovering from system failures, and coordinating distributed transactions.


The authors emphasize formal models that are easily applied across fields, that promise to remain valid as current technologies evolve, and that lend themselves to generalization and extension in the development of new classes of network-centric, functionally rich applications. This book's purpose and achievement is the presentation of the foundations of transactional systems as well as the practical aspects of the field what will help you meet today's challenges.

* Provides the most advanced coverage of the topic available anywhere--along with the database background required for you to make full use of this material.
* Explores transaction processing both generically as a broadly applicable set of information technology practices and specifically as a group of techniques for meeting the goals of your enterprise.
* Contains information essential to developers of Web-based e-Commerce functionality--and a wide range of more "traditional" applications.
* Details the algorithms underlying core transaction processing functionality.

Table of Contents

PART ONE - BACKGROUND AND MOTIVATION
Chapter 1 What Is It All About?
Chapter 2 Computational Models
PART TWO - CONCURRENCY CONTROL
Chapter 3 Concurrency Control: Notions of Correctness for the Page Model
Chapter 4 Concurrency Control Algorithms
Chapter 5 Multiversion Concurrency Control
Chapter 6 Concurrency Control on Objects: Notions of Correctness
Chapter 7 Concurrency Control Algorithms on Objects
Chapter 8 Concurrency Control on Relational Databases
Chapter 9 Concurrency Control on Search Structures
Chapter 10 Implementation and Pragmatic Issues
PART THREE - RECOVERY
Chapter 11 Transaction Recovery 
Chapter 12 Crash Recovery: Notion of Correctness
Chapter 13 Page Model Crash Recovery Algorithms
Chapter 14 Object Model Crash Recovery
Chapter 15 Special Issues of Recovery
Chapter 16 Media Recovery
Chapter 17 Application Recovery
PART FOUR - COORDINATION OF DISTRIBUTED TRANSACTIONS
Chapter 18 Distributed Concurrency Control
Chapter 19 Distributed Transaction Recovery
PART FIVE - APPLICATIONS AND FUTURE PERSPECTIVES
Chapter 20 What Is Next?

Transactional Information Systems: Theory, Algorithms, and the Practice of Concurrency Control and Recovery

Fault tolerance is a key requirement in process support systems (PSS), a class of distributed computing middleware encompassing applications such as workflow management systems and process centered software engineering environments. A PSS controls the flow of work between programs and users in networked environments based on a "metaprogram" (the process). The resulting applications are characterized by a high degree of distribution and a high degree of heterogeneity (properties that make fault tolerance both highly desirable and difficult to achieve). We present a solution for implementing more reliable processes by using exception handling, as it is used in programming languages, and atomicity, as it is known from the transaction concept in database management systems. We describe the mechanism incorporating both transactions and exceptions and present a validation technique allowing to assess the correctness of process specifications.

/pdf/exception-handling-in-workflow-management-systems-50xm2f4smf.pdf

Exception handling in workflow management systems

In this report, we present the approach to cross-organizational workflow management of the CrossFlow project. CrossFlow is a European research project aiming at the support of cross-organizational workflows in dynamic virtual enterprises. The cooperation in these virtual enterprises is based on dynamic service outsourcing specified in electronic contracts. Service enactment is performed by dynamically linking the workflow management infrastructures of the involved organizations. Extended service enactment support is provided in the form of cross-organizational transaction management and process control, advanced quality of service monitoring, and support for high-level flexibility in service enactment. CrossFlow technology is realized on top of a commercial workflow management platform and applied in two real-world scenarios in the contexts of a logistics and an insurance company.

CrossFlow: Cross-Organizational Workflow Management in Dynamic Virtual Enterprises

This paper gives a detailed overview of the approach to cross-organizational workflow management developed in the CrossFlow project. CrossFlow is a European research project aiming at the support of cross-organizational workflows in dynamic virtual enterprises. The cooperation in these virtual enterprises is based on dynamic service outsourcing specified in electronic contracts. Service enactment is performed by dynamically linking the workflow management infrastructures of the involved organizations. Extended service enactment support is provided in the form of cross-organizational transaction management and process control, advanced quality of service monitoring, and support for high-level flexibility in service enactment. CrossFlow technology is realized on top of a commercial workflow management platform and applied in two real-world scenarios in the contexts of a logistics and an insurance company.

/pdf/crossflow-cross-organizational-workflow-management-in-2zy9imc2l9.pdf

In this paper, we present quality of service (QoS) metrics for various network applications based on human factors and technology attributes. The first term, human factors, addresses human perception of different kinds of media, such as conventional text, audio and video. The second term, technology attributes, represents the different technological aspects of these network applications, such as time-dependence and symmetry. Both of these terms are key factors that lead to variations of requirements for QoS. Establishing these requirements is paramount to providing QoS on computer networks and the Internet. With the metrics presented in this paper we can provide the criteria necessary for such QoS assurance.

https://www.cic.unb.br/~pris/resources/Teaching/ConvRedes/QoSRequirements.pdf

QoS Requirements of Network Applications on the Internet

The security level of networks and systems is determined by the software vulnerabilities of its elements. Defending against large scale attacks requires a quantitative understanding of the vulnerability lifecycle. Specifically, one has to understand how exploitation and remediation of vulnerabilities, as well as the distribution of information thereof is handled by industry.In this paper, we examine how vulnerabilities are handled in large-scale, analyzing more than 80,000 security advisories published since 1995. Based on this information, we quantify the performance of the security industry as a whole. We discover trends and discuss their implications. We quantify the gap between exploit and patch availability and provide an analytical representation of our data which lays the foundation for further analysis and risk management.

/pdf/large-scale-vulnerability-analysis-3qlre7se58.pdf

Large-scale vulnerability analysis

The Internet and the proliferation of inexpensive computing power in the form of clusters of workstations or PCs provide the basic hardware infrastructure for business-to-business electronic commerce in small and medium enterprises (SMEs). Unfortunately, the corresponding software infrastructure is still missing. In this paper, we show a way to develop appropriate tools for electronic commerce by describing the approach we have taken in the WISE (Workflow-based Internet SErvices) project. The goals of WISE are to develop and deploy the software infrastructure that is necessary to support business-to-business electronic commerce in the form of virtual enterprises. The idea is to combine the tools and services of different companies as building blocks of a higher-level system in which a process acts as the blueprint for control and data flow within the virtual enterprise. From this idea, the final goal is to build the basic support for an Internet trading community where enterprises can join their services to provide value-added processes.

WISE: business to business e-commerce

The question of our study is how to provision a diffserv (differentiated service) intra-net serving three classes of traffic, i.e., voice, real-time data (e.g. stock quotes), and best-effort data. Each class of traffic requires a different level of QoS (Quality of Service) guarantee. For VoIP the primary QoS requirements are delay and loss; for realtime data response-time. Given a network configuration and anticipated workload of a business intra-net, we use ns-2 simulations to determine the minimum capacity requirements that dominate total cost of the intranet. To ensure that it is worthwhile converging different traffic classes or deploying diffserv, we cautiously examine capacity requirements in three sets of experiments: three traffic classes in i) three dedicated networks, ii) one network without diffserv support, and iii) one network with diffserv support. We find that for the business intra-net of our study, integration without diffserv may need considerable over-provisioning depending on the fraction of real-time data in the network. In addition, we observe significant capacity savings in the diffserv case; thus conclude that deploying diffserv is advantageous. The relations we find give rise to, as far as we know, the first rule of thumb on provisioning a diffserv network for increasing real-time data.

Towards Provisioning Diffserv Intra-Nets

A popular way to achieve frequency synchronization between devices (2, 3) over a packet-switched network (1) is by time stamping packets upon sending and receiving and analyzing sequences of time stamps at the receiver's side. The proposed invention gives a method to compute continuous accurate estimates of the frequency difference of sender and receiver clock as required e.g, in TDM circuit emulation over packet-switched networks (1). The essence of the invention is to segregate effects from clock frequency deviation from network dynamics. This segregation is achieved by estimating the minimal delay of the transmission over the network (1) from sequences of time stamps pairs. The method considers a history (h n ) of tuples (m, d) associated with packets. A tuples (m, d) consist of packet number (m) and difference (d) of receiver time and sender time. The method then successively upgrades the lower convex hull on a small superset of the tuples (m, d) in the history when new packets arrive. The method estimates the clock frequency difference by computing a «tangent» to this hull, i.e. by solving the associated linear programming on the superset. We denote that only the data of the hull needs to be kept in the memory of the receiver and not the full history data.

Method for frequency synchronization

Simulations with web traffic usually generate input by sampling a heavy-tailed object size distribution. As a consequence these simulations remain in transient state over all periods of time, i.e. all statistics that depend on moments of this distribution, such as the average object size or the average user-perceived latency of downloads, do not converge within periods practically feasible for simulations. We therefore investigate whether the 95-th, 98-th, and 99-th latency percentiles, which do not depend on the extreme tail of the latency distribution, are more suitable statistics for the performance evaluation. We exploit that corresponding object size percentiles in samples from a heavy-tailed distribution converge to normal distributions during periods feasible for simulations. Conducting a simulation study with ns-2, we find a similar convergence for network latency percentiles. We explain this finding with probability theory and propose a method to reliably test for this convergence.

Ulrich Fiedler

Papers

Large-scale vulnerability analysis

WISE: business to business e-commerce

Towards Provisioning Diffserv Intra-Nets

Method for frequency synchronization

Using latency quantiles to engineer QoS guarantees for web services