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R* Optimizer Validation and Performance Evaluation for Distributed Queries

Lothar F. Mackert and Guy M. Lohman

Summary by: Steve Gribble and Armando Fox

One-line summary: Measurement experiments affirming the efficacy of the R* query optimizer, access path selector, and cost models; for cross-site joins, the strategy of shipping the inner relation to the outer relation site was optimal in nearly all situations, and performing bloom-joins (hashed joins) consistenly outperformed semijoins.


Modeling the cost of a distributed query is difficult, and of course mistakes in access path selection could be exceedingly expensive. This study is sorely needed, although I don't think it was adequately broad or deep.


Overview/Main Points

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