for ( SinkOperator op : roots){
PhysicalOperator pop = op.accept(converter, obj);
physOps.add(pop);
}
PlanProperties props = new PlanProperties();
props.type = PlanProperties.PlanType.APACHE_DRILL_PHYSICAL;
props.version = plan.getProperties().version;
props.generator = plan.getProperties().generator;
PhysicalPlan p = new PhysicalPlan(props, physOps);
return p;