@Override
public Result execute() {
Result inResult1 = getInputTerm1().execute();
Result inResult2 = getInputTerm2().execute();
SemiJoinOperator oper = new SemiJoinOperator(Utils.getCaf(), inResult1.getResultRelation(), index1, inResult2.getResultRelation(), index2);
inResult1.extend(inResult2);
inResult1.extend(oper);
storeResult(inResult1);
return inResult1;
}