code: package it.unibz.inf.ontop.iq.planner;
  
  import it.unibz.inf.ontop.iq.optimizer.IQOptimizer;
  
  /**
   * By contrast to structural and semantic optimizations, the query planner can explore decisions that
   *  "it might regret afterwards" in isolated branches.
   *
   *  Serious query planners are supposed to take into account statistical information about the data source,
   *  while structural and semantic optimizations do not consider this kind of information.
   *
   */
  public interface QueryPlanner extends IQOptimizer {
  }
  