A parallel transitive closure algorithm using hash-based clustering

Cheiney, Jean-Pierre; Maindreville, Christophe de

doi:10.1007/3-540-51324-8_43

Cited by 11 publications

(13 citation statements)

References 6 publications

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“…(see Refs. [2][3][4][5]. However, the topology of the input graph has proved to be problematic, since there is no model in which the speedup can be represented as a function of the topology.…”

Section: A New Methodology For Analyzing Parallel Graph Algorithmsmentioning

confidence: 98%

Parallel processing of graph reachability in databases

Wolfson

Zhang

Butani

et al. 1992

Int J Parallel Prog

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In this paper we consider parallel processing of a graph represented by a database relation, and we achieved two objectives. First, we propose a methodology for analyzing the speedup of a parallel processing strategy with the purpose of selecting at runtime one of several candidate strategies, depending on the hardware architecture and the input graph. Second, we study the singlesource reachability problem, namely the problem of computing the set of nodes reachable from a given node in a directed graph. We propose several parallel strategies for solving this problem, and we analyze their performance using our new methodology. The analysis is confirmed experimentally in a UNIXEthernet environment. We also extend the results to the transitive closure problem.

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Section: A New Methodology For Analyzing Parallel Graph Algorithmsmentioning

confidence: 98%

Parallel processing of graph reachability in databases

Wolfson

Zhang

Butani

et al. 1992

Int J Parallel Prog

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“…In [17], Cheiney and de Maindreville show a simple extension of the evaluation strategy by Valduriez and Khoshafian that avoids rehashing deltas at each iteration step. This strategy is shown in Figure 185 .…”

Section: The Methods By Cheiney and De Maindrevillementioning

confidence: 99%

“…We start by discussing the approach of Valduriez and Khoshafian [61], then we discuss extensions of this approach described by Cheiney and de Maindreville [17] and Agrawal and Jagadish [4].…”

Section: Hash-based Fragmentationmentioning

confidence: 99%

A survey of parallel execution strategies for transitive closure and logic programs

Cacace

Ceri

Houtsma

1993

Distrib Parallel Databases

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An important feature of database technology of the nineties is the use of parallelism for speeding up the execution of complex queries. This technology is being tested in several experimental database architectures and a few commercial systems for conventional select-project-join queries. In particular, hash-based fragmentation is used to distribute data to disks under the control of different processors in order to perform selections and joins in parallel. With the development of new query languages, and in particular with the definition of transitive closure queries and of more general logic programming queries, the new dimension of recursion has been added to query processing. Recursive queries are complex; at the same time, their regular structure is particularly suited for parallel execution, and parallelism may give a high efficiency gain. We survey the approaches to parallel execution of recursive queries that have been presented in the recent literature. We observe that research on parallel execution of recursive queries is separated into two distinct subareas, one focused on the transitive closure of Relational Algebra expressions, the other one focused on optimization of more general Datalog queries. Though the subareas seem radically different because of the approach and formalism used, they have many common features. This is not surprising, because most typical Datalog queries can be solved by means of the transitive closure of simple algebraic expressions. We first analyze the relationship between the transitive closure of expressions in Relational Algebra and Datalog programs. We then review sequential methods for evaluating transitive closure, distinguishing iterative and direct methods. We address the parallelization of these methods, by discussing various forms of parallelization. Data fragmentation plays an important role in obtaining parallel execution; we describe hash-based and semantic fragmentation. Finally, we consider Datalog queries, and present general methods for parallel rule execution; we recognize the similarities between these methods and the methods reviewed previously, when the former are applied to linear Datalog queries. We also provide a quantitative analysis that shows the impact of the initial data distribution on the performance of methods.

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“…Other work concerned with the parallel computation of transitive closure queries includes [35] and [36].…”

Section: Previous Related Workmentioning

confidence: 99%

Evaluating recursive queries in distributed databases

Nejdl

Ceri²,

Wiederhold³

1993

IEEE Trans. Knowl. Data Eng.

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In this paper, we study the execution of logic queries in a distributed database environment. We assume that each local database system can execute logic queries, and we design methods for the efficient execution of queries requiring data from multiple sites. Conventional optimization strategies which are well known in the field of distributed databases, such as the early evaluation of selection conditions and the clustering of processing to manipulate and exchange large sets of tuples, are redefined in view of the additional difficulties due to logic queries, in particular to recursive rules.In order to allow efficient processing of these logic queries we present several program transformation techniques which attempt to minimize distribution costs based on the idea of semi-joins and generalized semi-joins in conventional databases. Although local computation of semi-joins is not possible for the general case, we indicate classes of programs for which these transformations succeed in producing set-oriented computation. We describe processes evaluating the recursive program in a distributed network and develop an efficient method for testing the termination of the computation. Finally, we compare our approach with sequential as well as dataflow-oriented evaluation. Datalog is assumed as logic programming language and paradigm.

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A parallel transitive closure algorithm using hash-based clustering

Cited by 11 publications

References 6 publications

Parallel processing of graph reachability in databases

Parallel processing of graph reachability in databases

A survey of parallel execution strategies for transitive closure and logic programs

Evaluating recursive queries in distributed databases

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