Distributed databases principles and systems
Distributed databases principles and systems
Optimizing Join Queries in Distributed Databases
IEEE Transactions on Software Engineering
Optimizing Joins in Fragmented Database Systems on a Broadcast Local Network
IEEE Transactions on Software Engineering
Statistical profile estimation in database systems
ACM Computing Surveys (CSUR)
On the effect of join operations on relation sizes
ACM Transactions on Database Systems (TODS)
Optimal Semijoins for Distributed Database Systems
IEEE Transactions on Software Engineering
Optimizing equijoin queries in distributed databases where relations are hash partitioned
ACM Transactions on Database Systems (TODS)
On the propagation of errors in the size of join results
SIGMOD '91 Proceedings of the 1991 ACM SIGMOD international conference on Management of data
Join processing in relational databases
ACM Computing Surveys (CSUR)
Design and implementation of a query processor for a trusted distributed data base management system
Journal of Systems and Software
SIGMOD '93 Proceedings of the 1993 ACM SIGMOD international conference on Management of data
Parallelism in relational database management systems
IBM Systems Journal
Query processing in a system for distributed databases (SDD-1)
ACM Transactions on Database Systems (TODS)
An Intelligent Search Method for Query Optimization by Semijoins
IEEE Transactions on Knowledge and Data Engineering
A Graph Theoretical Approach to Determine a Join Reducer Sequence in Distributed Query Processing
IEEE Transactions on Knowledge and Data Engineering
On the Complexity of Distributed Query Optimization
IEEE Transactions on Knowledge and Data Engineering
A Parallel Execution Method for Minimizing Distributed Query Response Time
IEEE Transactions on Parallel and Distributed Systems
Interleaving a Join Sequence with Semijoins in Distributed Query Processing
IEEE Transactions on Parallel and Distributed Systems
Combining Joint and Semi-Join Operations for Distributed Query Processing
IEEE Transactions on Knowledge and Data Engineering
Sampling-Based Estimation of the Number of Distinct Values of an Attribute
VLDB '95 Proceedings of the 21th International Conference on Very Large Data Bases
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The optimization of general queries in a distributed database management system is an important and challenging research issue. The problem is to find an optimal evaluation strategy for a given general query. In this paper, we propose an approach based on a combination of join and parallel semijoin operations to minimize the amount of data transmission in distributed query processing. First, we describe an efficient distributed query processing strategy using only semijoins. This strategy selects an optimal set instead of a sequence of semijoins to be executed in parallel in three phases: a projection phase, a transmission phase and a reduction phase. Then, we apply a sequence of joins as reducers for query processing. Furthermore, we consider the problem of finding an optimal general sequence that fully reduces a general join query graph. We present a new method that combines parallel and sequential semijoins. We report on experiments that show that our approach based on parallel semijoins is not only efficient but also effective in reducing the total amount of data transmission required to process distributed queries.