public PhysicalOperator getPhysicalOperator(PhysicalPlanCreator creator) throws IOException {
Prel child = (Prel) this.getChild();
PhysicalOperator childPOP = child.getPhysicalOperator(creator);
ProducerConsumer pop = new ProducerConsumer(childPOP, queueSize);
return creator.addMetadata(this, pop);
}