// add new filter op
List<Operator<? extends Serializable>> originalChilren = op.getChildOperators();
op.setChildOperators(null);
Operator<filterDesc> output =
OperatorFactory.getAndMakeChild(new filterDesc(condn, false),
new RowSchema(inputRR.getColumnInfos()),
op);
output.setChildOperators(originalChilren);
for (Operator<? extends Serializable> ch : originalChilren) {
List<Operator<? extends Serializable>> parentOperators = ch.getParentOperators();