Several works refer to the cost of processing queries over a distributed database
or query optimization (query plan selection) in such context (Kossman & Stocker,
2000; Sasha, Wang, & Tsong-Li, 1991; Steinbrunn, Moerkotte, & Kemper, 1997;
Yu, Guh, Brill, & Chen, 1989).
Yu et al. (1989) consider partitioning, local processing, and data communication
costs in their cost model, to determine which relations should be partitioned and
replicated, considering that no relation is prepartitioned. Algorithms and optimizations
for parallel processing of multiway joins over hash-partitioned relations are
considered by Sasha et al. (1991). The authors also introduce a cost model and propose
algorithms to determine the most efficient join order for multiway joins over fully
partitioned relations in a shared-nothing cluster. Some works (Kossman & Stocker,
2000; Steinbrunn et al., 1997) consider heuristic search for the best overall execution
plan, considering that the search for the optimal plan is an NP-hard problem.
Low.Bandwidth.and.Early.Selection.
Another factor that affects the efficiency of partitioning schemes is the ???available
bandwidth.??? Given that the network interconnecting the computer nodes may be
slow, nondedicated, or the system may be running several queries simultaneously,
it is important to take into account the possibility of low available bandwidth.
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