}
public static ExchangeCost getSimpleEstimate(Size s){
long cnt = s.getRecordCount();
int sz = s.getRecordSize();
OperatorCost send = new OperatorCost(cnt*sz, 0, 0, cnt);
OperatorCost receive = new OperatorCost(cnt*sz, 0, 0, cnt);
return new ExchangeCost(send, receive);
}