public LocalJob execute(ExecPhysicalPlan plan) throws ExecException {
DataBag results = BagFactory.getInstance().newDefaultBag();
try {
PhysicalOperator pp = (PhysicalOperator)physicalOpTable.get(plan.getRoot());
pp.visit(new InstantiateFuncCallerPOVisitor(pigContext, physicalOpTable));
pp.open();
Tuple t;
while ((t = (Tuple) pp.getNext()) != null) {
results.add(t);