Execution in a Parallel Main - Memory EnvironmentAnnita
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چکیده
In this paper, the performance and characteristics of the execution of various join-trees on a parallel DBMS are studied. The results of this study, are a step into the direction of the design of a query optimization strategy that is t for parallel execution of complex queries. Among others, synchronization issues are identiied to limit the performance gain from parallelism. A new hash-join algorithm, called Pipelining hash-join is introduced that has fewer synchronization constraints than the known hash-join algorithms. Also, the behavior of individual join operations in a join-tree is studied in a simulation experiment. The results show that the Pipelining hash-join algorithm yields a better performance for multi-join queries. Also, the format of the optimal join-tree appears to depend on the size of the operands of the join: A multi-join between small operands performs best with a bushy schedule; larger operands are better oo with a linear schedule. The results from the simulation study are connrmed with an analytic model for dataaow query execution.
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تاریخ انتشار 1991