The one-shot semi-join reduction approach was applied to reducing distributed query response time under the assumption that one copy of each referenced relation has been chosen prior to the production of an exe
A semijoin program is a query execution plan for queries to distributed database systems that uses semijoins to reduce the size of relation instances before they are transmitted and further joined. Yet the reduction itself requires that a projection of the relation instances involved in the join ...
For each semijoin Rj o(A •i, a selectivity factor, ilia =- ]RI~A(IA)]is used to predict the reduction effect. After the execution of Rj OCARi, the size of Rj becomes PiAIIRill. Morever, it is important to verify that a semijoin Rj (XA Ri is profitable, i.e. if the ...
On-line data reduction and the quality of history in moving objects databases 2006, MobiDE 2006: Proceedings of the 5th ACM International Workshop on Data Engineering for Wireless and Mobile Access Continuous reverse nearest neighbor monitoring 2006, Proceedings - International Conference on Data Engine...
This paper presents "Positionally Encoded Record Filters " (PERFs) and describes their use in a distributed query processing technique called PERF join. A PERF is a novel two-way join reduction implementation primitive. While having the same storage and transmission efficiency as a hash filter (e...
The directed graph of all admissible move sequences is formed. An optimization process includes dynamically generating good estimations for the target distance of a search state. Some heuristics are disclosed for providing start solutions for the optimization process.Hill, Gerhard L.Peh, Thomas...
An optimization process includes dynamically generating good estimations for the target distance of a search state. Some heuristics are disclosed for providing start solutions for the optimization process.doi:US8271478 B2Gerhard L. HillThomas PehUS...
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 ...
The performance study of our technique shows the reduction of the communication costs in the semi-join based join operation. Our technique can be deployed in large scale peer to peer or grid environments especially in a network with low bandwidth and strong latency....
The grid-ID-based approximation provides great reduction in communication cost by approximating many spatial objects in simpler forms. Our experiments demonstrate that the algorithm outperforms existing methods in reducing energy consumption at the nodes....