Disk timeslicing is a promising technique for storage performance insulation. To work with cluster-based storage, however, timeslices associated with striped data must be co-scheduled on the corresponding servers. Thi...
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ISBN:
(纸本)9780769538266
Disk timeslicing is a promising technique for storage performance insulation. To work with cluster-based storage, however, timeslices associated with striped data must be co-scheduled on the corresponding servers. This paper describes algorithms for determining global timeslice schedules and mechanisms for coordinating the independent server activities. Experiments with a prototype show that, combined, they can provide performance insulation for workloads sharing a storage cluster - each workload realizes a configured minimum efficiency within its timeslices regardless of the activities of the other workloads.
Skew in the distribution of values taken by an attribute is identified as a major factor that can affect the performance of parallel architectures for relational joins. The effect of skew on the performance of two par...
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ISBN:
(纸本)0818608935
Skew in the distribution of values taken by an attribute is identified as a major factor that can affect the performance of parallel architectures for relational joins. The effect of skew on the performance of two parallel architectures is evaluated using analytic models. In one architecture, called database machine (DBMC), data as well as processing power are distributed;while in the other architecture, called single processor parallel input/output (SPPI), data is distributed but the processing power is concentrated in one processor. The two architectures are compared in terms of the ratio of MIPS (millions of instructions per second) used by DBMC and SPPI to deliver the same throughput and response time. In addition, the horizontal growth potential of DBMC is evaluated in terms of maximum speedup achievable by DBMC relative to SPPI response time. The MIPS ratio as well as speedup are found to be very sensitive to the amount of skew. These suggest that careful thought should be given in parallelizing database applications and in the design of algorithms and query optimizer for parallel architectures.
Query caching has been utilized efficiently to improve query processing in distributed database environments. Most prior caching techniques are based on single-level caching of previous query results. This is basicall...
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ISBN:
(纸本)0780382927
Query caching has been utilized efficiently to improve query processing in distributed database environments. Most prior caching techniques are based on single-level caching of previous query results. This is basically to avoid accessing the underlying databases each time a user submits the same query. In this paper, we propose a new methodology that allows caching a combination of both plans and results of prior queries in a multilevel caching architecture. The objective is to reduce the response time of distributed query processing and hence increase the system throughput.
Approximation of partial differential equations of hyperbolic type by a set of ordinary differential equations is presented. The method of weighted-residual is applied. The Galerkin method and the finite element metho...
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ISBN:
(纸本)0780312813
Approximation of partial differential equations of hyperbolic type by a set of ordinary differential equations is presented. The method of weighted-residual is applied. The Galerkin method and the finite element method are presented as examples.
GRIDs are large-scale distributed computing infrastructures that enable the integrated and collaborative use of high-end computers, networks, databases, and scientific instruments owned and managed by multiple organiz...
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An efficient architecture for a FPGA symmetry FIR filter is proposed that employs M-bit parallel-distributed arithmetic (M-bit PDA). The partial product is pre-calculated and saved into the distributed RAM. This elimi...
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ISBN:
(纸本)9780780393899
An efficient architecture for a FPGA symmetry FIR filter is proposed that employs M-bit parallel-distributed arithmetic (M-bit PDA). The partial product is pre-calculated and saved into the distributed RAM. This eliminates the large amount of logic needed to compute multiplication results. The proposed architecture consumes less area and offers higher speed operation because the multiplier is omitted. Altera APEX20KE is used as a target device. Thus, the proposed architecture has high processing speed and small area.
Component software is a promising approach for dealing with the problem of large scale distributed system development, because it decreases development costs and increases software quality. One of the central issues f...
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ISBN:
(纸本)0769506348
Component software is a promising approach for dealing with the problem of large scale distributed system development, because it decreases development costs and increases software quality. One of the central issues for component software in distributedsystems is the location of components. In large scale distributedsystems trading is already used as a service location mechanism. This is considered the only way to manage services in large scab distributedsystems where complete knowledge of the system is both unreasonable and unrealistic. Providing trading mechanisms appropriate for component development requires a move from appearance based (interface) to behaviour based (semantic) trading. We present a semantically enhanced component trading architecture that enables this move.
Efficient distribution of data is a major challenge in distributeddatabases. The problem is even more severe for distributed object oriented databases because of inheritance, encapsulation and the more complex proble...
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ISBN:
(纸本)188084348X
Efficient distribution of data is a major challenge in distributeddatabases. The problem is even more severe for distributed object oriented databases because of inheritance, encapsulation and the more complex problem involved when methods invoke other methods. This problem is a harder version of the relational database allocation problem (DAP), a problem known to be NP-haxd. We looked at the problem of developing an efficient heuristic for allocating object fragments in a distributed object oriented database. To accomplish this we created a genetic algorithm which produced more favorable results as compared to the graphical algorithm of Barker and Bhar [2]. Our results show near optimal allocation for those configurations in which the optimal could be computed, improvement over the graphical algorithm and has a linear running time.
In today's workstation based environment, applications such as design databases, multimedia databases, and knowledge bases do not fit well into the relational data processing framework. The object-oriented data mo...
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ISBN:
(纸本)081864222X
In today's workstation based environment, applications such as design databases, multimedia databases, and knowledge bases do not fit well into the relational data processing framework. The object-oriented data model has been proposed to model and process such complex databases. Due to the nature of the supported applications, object-oriented database systems need efficient mechanisms for the retrieval of complex objects and the navigation along the semantic links among objects. Object clustering and buffering have been suggested as efficient mechanisms for the retrieval of complex objects. However, to improve the efficiency of the aforementioned operations, one has to look at the recent advances in storage technology. This paper is an attempt to investigate the feasibility of using parallel disks for object-oriented databases. It analyzes the conceptual changes needed to map the clustering and buffering schemes proposed in [8,9] on the new underlying architecture. The simulation and performance evaluation of the proposed leveled-clustering and mapping schemes utilizing parallel I/O disks are presented and analyzed.
In this paper, we propose a new algorithm named parallel Multipass with Inverted Hashing and Pruning (PMIHP) for mining association rules between words in text databases. The characteristics of text databases are quit...
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ISBN:
(纸本)0769521320
In this paper, we propose a new algorithm named parallel Multipass with Inverted Hashing and Pruning (PMIHP) for mining association rules between words in text databases. The characteristics of text databases are quite different from those of retail transaction databases, and existing mining algorithms cannot handle text databases efficiently because of the large number of itemsets (i.e., sets of words) that need to be counted. The new PMIHP algorithm is a parallel version of our Multipass with Inverted Hashing and Pruning (MIHP) algorithm [13], which was shown to be quite efficient than other existing algorithms in the context of mining text databases. The PMIHP algorithm reduces the overhead of communication between miners running on different processors because they are mining local databases asynchronously and prune the global candidates by using the Inverted Hashing and Pruning technique. Compared with the well-known Count Distribution algorithm [2], PMIHP demonstrates superior performance characteristics for mining association rules in large text databases, and when the minimum support level is low, its speedup is superlinear as the number of processors increases. These experiments were performed on a cluster of Linux workstations using a collection of Wall Street Journal articles.
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