Mostafa Bamha

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The development of scalable parallel database systems requires the design of efficient algorithms for the join operation which is the most frequent and expensive operation in relational database systems. The join is also the most vulnerable operation to data skew and to the high cost of communication in distributed architectures. In this paper, we present a(More)
Semi-join is the most used technique to optimize the treatment of complex relational queries on distributed architectures. However, the overhead related to semi-join computation can be very high due to data skew and to the high cost of communication in distributed architectures. Internet search engines needs to process vast amounts of raw data every day.(More)
The problem of maintenance of materialized views has been the object of increased research activity recently mainly because of applications related to data warehousing. Many sequential view maintenance algorithms are developed in the literature. If the view is deened by a relational expression involving join operators, the cost of re-evaluating the view(More)
SQL queries involving join and group-by operations are frequently used in many decision support applications. In these applications, the size of the input relations is usually very large, so the parallelization of these queries is highly recommended in order to obtain a desirable response time. The main drawbacks of the presented parallel algorithms that(More)
The NESL parallel functional language developed at CMU supports a combination of data-and control parallelism through so-called nested parallelism. The designers of NESL have deened the portable intermediate language VCODE into which NESL is compiled. VCODE realises nested parallelism by data structures called segmented vectors akin to lists of lists.(More)