This third edition of a classic textbook can be used to teach at the senior undergraduate and graduate levels. The material concentrates on fundamental theories as well as techniques and algorithms. The advent of the Internet and the World Wide Web, and, more recently, the emergence of cloud computing and streaming data applications, has forced a renewal of interest in distributed and parallel data management, while, at the same time, requiring a rethinking of some of the traditional techniques. This book covers the breadth and depth of this re-emerging field. The coverage consists of two parts. The first part discusses the fundamental principles of distributed data management and includes distribution design, data integration, distributed query processing and optimization, distributed transaction management, and replication. The second part focuses on more advanced topics and includes discussion of parallel database systems, distributed object management, peer-to-peer data management, web data management, data stream systems, and cloud computing. New in this Edition: New chapters, covering database replication, database integration, multidatabase query processing, peer-to-peer data management, and web data management. Coverage of emerging topics such as data streams and cloud computing Extensive revisions and updates based on years of class testing and feedback Ancillary teaching materials are available.

Principles of Distributed Database Systems

This report presents a unified approach for the study of constrained Markov decision processes with a countable state space and unbounded costs. We consider a single controller having several objectives; it is desirable to design a controller that minimize one of cost objective, subject to inequality constraints on other cost objectives. The objectives that we study are both the expected average cost, as well as the expected total cost (of which the discounted cost is a special case). We provide two frameworks: the case were costs are bounded below, as well as the contracting framework. We characterize the set of achievable expected occupation measures as well as performance vectors. This allows us to reduce the original control dynamic problem into an infinite Linear Programming. We present a Lagrangian approach that enables us to obtain sensitivity analysis. In particular, we obtain asymptotical results for the constrained control problem: convergence of both the value and the policies in the time horizon and in the discount factor. Finally, we present and several state truncation algorithms that enable to approximate the solution of the original control problem via finite linear programs.

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Constrained Markov Decision Processes

Database management systems will continue to manage large data volumes. Thus, efficient algorithms for accessing and manipulating large sets and sequences will be required to provide acceptable performance. The advent of object-oriented and extensible database systems will not solve this problem. On the contrary, modern data models exacerbate the problem: In order to manipulate large sets of complex objects as efficiently as today's database systems manipulate simple records, query-processing algorithms and software will become more complex, and a solid understanding of algorithm and architectural issues is essential for the designer of database management software. This survey provides a foundation for the design and implementation of query execution facilities in new database management systems. It describes a wide array of practical query evaluation techniques for both relational and postrelational database systems, including iterative execution of complex query evaluation plans, the duality of sort- and hash-based set-matching algorithms, types of parallel query execution and their implementation, and special operators for emerging database application domains.

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Query evaluation techniques for large databases

Planning under uncertainty is a central problem in the study of automated sequential decision making, and has been addressed by researchers in many different fields, including AI planning, decision analysis, operations research, control theory and economics. While the assumptions and perspectives adopted in these areas often differ in substantial ways, many planning problems of interest to researchers in these fields can be modeled as Markov decision processes (MDPs) and analyzed using the techniques of decision theory.

This paper presents an overview and synthesis of MDP-related methods, showing how they provide a unifying framework for modeling many classes of planning problems studied in AI. It also describes structural properties of MDPs that, when exhibited by particular classes of problems, can be exploited in the construction of optimal or approximately optimal policies or plans. Planning problems commonly possess structure in the reward and value functions used to describe performance criteria, in the functions used to describe state transitions and observations, and in the relationships among features used to describe states, actions, rewards, and observations.

Specialized representations, and algorithms employing these representations, can achieve computational leverage by exploiting these various forms of structure. Certain AI techniques-- in particular those based on the use of structured, intensional representations--can be viewed in this way. This paper surveys several types of representations for both classical and decision-theoretic planning problems, and planning algorithms that exploit these representations in a number of different ways to ease the computational burden of constructing policies or plans. It focuses primarily on abstraction, aggregation and decomposition techniques based on AI-style representations.

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Decision-theoretic planning: structural assumptions and computational leverage

This work is a survey of the average cost control problem for discrete-time Markov processes. The authors have attempted to put together a comprehensive account of the considerable research on this problem over the past three decades. The exposition ranges from finite to Borel state and action spaces and includes a variety of methodologies to find and characterize optimal policies. The authors have included a brief historical perspective of the research efforts in this area and have compiled a substantial yet not exhaustive bibliography. The authors have also identified several important questions that are still open to investigation.

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Discrete-time controlled Markov processes with average cost criterion: a survey

We consider finite-state finite-action Markov decision processes which accumulate both a reward and a cost at each decision epoch. We study the problem of finding a policy that maximizes the expected long-run average reward subject to the constraint that the long-run average cost be no greater than a given value with probability one. We establish that if there exists a policy that meets the constraint, then there exists an e-optimal stationary policy. Furthermore, an algorithm is outlined to locate the e-optimal stationary policy. The proof of the result hinges on a decomposition of the state space into maximal recurrent classes and a set of transient states.

Multichain Markov decision processes with a sample path constraint: a decomposition approach

We consider time-average Markov Decision Processes MDPs, which accumulate a reward and cost at each decision epoch. A policy meets the sample-path constraint if the time-average cost is below a specified value with probability one. The optimization problem is to maximize the expected average reward over all policies that meet the sample-path constraint. The sample-path constraint is compared with the more commonly studied constraint of requiring the average expected cost to be less than a specified value. Although the two criteria are equivalent for certain classes of MDPs, their feasible and optimal policies differ for many nontrivial problems. In general, there does not exist optimal or nearly optimal stationary policies when the expected average-cost constraint is employed. Assuming that a policy exists that meets the sample-path constraint, we establish that there exist nearly optimal stationary policies for communicating MDPs. A parametric linear programming algorithm is given to construct nearly optimal stationary policies. The discussion relies on well known results from the theory of stochastic processes and linear programming. The techniques lead to simple proofs of the existence of optimal and nearly optimal stationary policies for unichain and deterministic MDPs, respectively.

Markov Decision Processes with Sample Path Constraints: The Communicating Case

Partitioning and allocation of relations is an important component of the distributed database design. Several approaches (and algorithms) have been proposed for clustering data for pattern classification and for partitioning relations in distributed databases. Most of the approaches used for classification use square-error criterion. In contrast, most of the approaches proposed for partitioning of relations are eitherad hoc solutions or solutions for special cases (e.g., binary vertical partitioning).

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An objective function for vertically partitioning relations in distributed databases and its analysis

In a distributed database system there is a need for periodic changes in data distribution due to such factors as changes in query patterns and network topology. A proper redistribution of data is necessary to provide acceptable system performance, as measured by the average execution time of transactions. The problem of properly scheduling data transfers in order to complete this redistribution process in minimum possible time is investigated. This problem takes into account the constraints on communication resources of the system. The complexity of the problem is discussed, and a useful upper bound for optimal solutions is presented. Also given are procedures for finding optimal and approximate solutions to this problem. >

Scheduling data redistribution in distributed databases

The n-ary vertical partitioning problem is addressed, and an objective function that generalizes and subsumes earlier work is derived. The objective function derived provides a basis for developing heuristic algorithms for vertical partitioning. The objective function is also useful for comparing previously proposed algorithms for vertical partitioning. The current implementation status of a testbed is indicated. >

Ravi Varadarajan

Papers

Multichain Markov decision processes with a sample path constraint: a decomposition approach

Markov Decision Processes with Sample Path Constraints: The Communicating Case

An objective function for vertically partitioning relations in distributed databases and its analysis

Scheduling data redistribution in distributed databases

A formal approach to the vertical partitioning problem in distributed database design