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Rule Documentation

All Packages - Package Correct Operatorgraph - Package Logical Optimization - Package Physical OptimizationFRAMES - NO FRAMES

Rule Binary Join

Short Description:

This transformation rule optimizes the join order for the Stream approach and generates only binary joins.

See also:

Optimizing Join Order

Long Description:

This transformation rule is only applied for the Stream approach. The operator graph can contain joins with more than two operands. In this case, this transformation rule generates several join operators, which have only two operands (in a deep right-tree) and which first join those triple patterns, which have the smallest number of not already bound variables. As the Stream approach must optimize before any read input data, it cannot use statistics about them for the optimization of the join order. Note that there are more sophisticated join ordering optimization implemented for the other approaches, which use different kinds of estimations.
All Packages - Package Correct Operatorgraph - Package Logical Optimization - Package Physical OptimizationFRAMES - NO FRAMES