PhysicalPlanReader reader = new PhysicalPlanReader(c, c.getMapper(), CoordinationProtos.DrillbitEndpoint.getDefaultInstance());
MockSubScanPOP s = new MockSubScanPOP("abc", null);
s.setOperatorId(3);
Filter f = new Filter(s, new ValueExpressions.BooleanExpression("true", ExpressionPosition.UNKNOWN), 0.1f);
f.setOperatorId(2);
UnionExchange e = new UnionExchange(f);
e.setOperatorId(1);
Screen screen = new Screen(e, CoordinationProtos.DrillbitEndpoint.getDefaultInstance());
screen.setOperatorId(0);
boolean reversed = false;
while(true){