Design of partially replicated distributed database systems: an integrated methodology

Abstract

The objective of this research is to develop and integrate tools for the design of partially replicated distributed database systems. Many existing tools are inappropriate for designing large-scale distributed databases due to their large computational requirements. Our goal is to develop tools that solve the design problems reasonably quickly, typically by using heuristic algorithms that provide approximate or near-optimal solutions. In developing this design methodology, we assume that information regarding the types of user requests and their rates of arrival into the system is known a priori . The methodology assumes a general model for transaction execution. In this paper we discuss three aspects of the design methodology: the data allocation problem, the use of a static load-balancing scheme in coordination with the allocation scheme, and the design evaluation and review step. Our methodology employs iterative design techniques using performance evaluation as a means to iterate.

A heuristic algorithm for determining a near-optimal set of nodes to access in a partially replicated distributed database system

“…Several variations of this general heuristic are possible due to the selection choices afforded by Steps (iii) and (iv). Twenty-seven possibilities are described and evaluated in [MUKK87]. For the sake of brevity we describe here only the heuristic with the best overall performance.…”

“…This heuristic is referred to as H12 in [MUKK87]. It is characterized by the following decision choices in the execution of the algorithm: In Step (iii), if several data items satisfy the minimum degree of freedom criteria, then H12 employs a random decision process to choose one among the several candidates.…”

“…H12, however, employs the concept of degree of relevance for such a choice. Employing a random decison process to choose from a set of candidates with the same characteristics has significantly improved the overall performance of our heuristic algorithm [MUKK87].…”