# Package org.eclipse.rdf4j.sail.federation.optimizers

- Class Summary
  Class | Description
  --- | ---
  EmptyPatternOptimizer | Remove StatementPatterns that have no statements.
  EvaluationStatistics | Supplies various query model statistics to the query engine/optimizer.
  EvaluationStatistics.CardinalityCalculator |
  FederationJoinOptimizer | Search for Join, LeftJoin, and Union arguments that can be evaluated in a single member.
  OwnedTupleExprPruner | Remove redundant `OwnedTupleExpr`.
  PrepareOwnedTupleExpr | Remove redundant `OwnedTupleExpr`.
  QueryModelPruner | A query optimizer that prunes query model trees by removing superfluous parts and/or by reducing complex parts with simpler parts.
  QueryMultiJoinOptimizer | A query optimizer that re-orders nested Joins.

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