Class ProjectionRemovalOptimizer

All Implemented Interfaces:

public class ProjectionRemovalOptimizer extends Object implements QueryOptimizer
If a projection node in the algebra does not contribute or change the results it can be removed from the tree. For example SELECT ?s ?p ?o WHERE {?s ?p ?o } Does not need a projection as the inner statement pattern returns the same result. While * SELECT ?s ?p WHERE {?s ?p ?o } Does as the statement pattern has one more variable in use than the projection. Note: this optimiser should run after optimisations ran that depend on Projections. e.g.
Jerven Bolleman
See Also:
  • Constructor Details

    • ProjectionRemovalOptimizer

      public ProjectionRemovalOptimizer()
  • Method Details