public PhysicalOperation visitProject(ProjectNode node, LocalExecutionPlanContext context)
{
PlanNode sourceNode;
Expression filterExpression;
if (node.getSource() instanceof FilterNode) {
FilterNode filterNode = (FilterNode) node.getSource();
sourceNode = filterNode.getSource();
filterExpression = filterNode.getPredicate();
}
else {
sourceNode = node.getSource();
filterExpression = BooleanLiteral.TRUE_LITERAL;
}