Many distributed applications require the knowledge of the causality relation induced by the computation. Reconstructing this relation appears to be an interesting tool for such applications, but a vector of size S - ...
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Many distributed applications require the knowledge of the causality relation induced by the computation. Reconstructing this relation appears to be an interesting tool for such applications, but a vector of size S - where S is the number of processes - must be attached to each event to achieve this reconstruction. This induces a large overhead in secondary memory. After defining special events of the computation - some kind of checkpoints - we propose two algorithms that discard unnecessary data for the causal relationship reconstruction. The first algorithm acts on-the-fly while the second acts during reconstruction.< >
The authors describe how the NonStop SQL relational database management system has implemented parallelism in the areas of query support, index maintenance, and database utilities, to provide higher levels of performa...
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The authors describe how the NonStop SQL relational database management system has implemented parallelism in the areas of query support, index maintenance, and database utilities, to provide higher levels of performance. The authors demonstrated that the use of parallelism significantly improves the response time for query processing, as well as for utility operations.< >
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 algorithm...
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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.< >
The TUXEDO system, a commercially proven transaction monitor, built on open industry standards, is described. It ensures data integrity in a distributed, heterogeneous environment with an optimized two-phase commit pr...
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The TUXEDO system, a commercially proven transaction monitor, built on open industry standards, is described. It ensures data integrity in a distributed, heterogeneous environment with an optimized two-phase commit protocol. It offers an advanced client/server programming paradigm, increased throughput, network connectivity, and runtime system monitoring and management.< >
The COMFORT project, which is intended to automate the performance tuning of database systems, is discussed. The project addresses several important tuning issues of parallel database systems in a multiuser environmen...
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The COMFORT project, which is intended to automate the performance tuning of database systems, is discussed. The project addresses several important tuning issues of parallel database systems in a multiuser environment, and it aims to develop general architectural principles for a self-tuning database system. The overall goals and the rationale are examined, and a brief overview of the current work is given.< >
The ACMS transaction processing (TP) monitor is discussed. ACMS enforces a unique, structured application programming style that makes it easy to develop/modify/reuse application modules. It supports a wide range of i...
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The ACMS transaction processing (TP) monitor is discussed. ACMS enforces a unique, structured application programming style that makes it easy to develop/modify/reuse application modules. It supports a wide range of industry-standard clients. CMS's scalable architecture gives it best-in-industry price/performance.< >
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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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 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.< >
The status of the DBS3 prototype, a parallel relational database system implemented on a shared everything architecture, is described. The following original aspects of its design are examined. First, DBS3 has a compi...
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The status of the DBS3 prototype, a parallel relational database system implemented on a shared everything architecture, is described. The following original aspects of its design are examined. First, DBS3 has a compilation approach (compiled C code) which allows a fine grain control of the execution. second, DBS3 optimizes and parallelizes queries in self-scheduled parallel programs supporting interoperator and intraoperator parallelism, as well as pipeline parallelism. Third, the underlying execution model is based on a distributed store model, allowing an efficient mapping of the produced code onto several classes of parallel architectures: DBS3 on shared everything, EDBS on shared nothing.< >
The impact on query processing performance of various physical organizations for inverted lists is compared. A probabilistic mode of the database and queries is introduced. Simulation experiments determine which varia...
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The impact on query processing performance of various physical organizations for inverted lists is compared. A probabilistic mode of the database and queries is introduced. Simulation experiments determine which variables most strongly influence response time and throughput. This leads to a set of design tradeoffs over a range of hardware configurations and new parallel query processing strategies.< >
The author discusses relational database management system portability and interoperability through the use of standards. The SQL Access Group has accelerated ongoing standards activities to define a single portabilit...
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The author discusses relational database management system portability and interoperability through the use of standards. The SQL Access Group has accelerated ongoing standards activities to define a single portability and interoperability standard that can be used by RDBMS and application vendors. The current status of SQL Access work is discussed, and future work items are indicated.< >
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