Method evalWithNulls

bolt/expression/Expr.cpp:1158–1194

      if (vector->mayHaveNulls()) {
        mayHaveNulls = true;
        break;
      }
    }

    if (mayHaveNulls) {
      LocalSelectivityVector nonNullHolder(context);
      if (removeSureNulls(rows, context, nonNullHolder)) {
        ScopedVarSetter noMoreNulls(context.mutableNullsPruned(), true);
        if (nonNullHolder.get()->hasSelections()) {
          evalAll(*nonNullHolder.get(), context, result);
        }
        auto rawNonNulls = nonNullHolder.get()->asRange().bits();
        addNulls(rows, rawNonNulls, context, result);
        return;
      }
    }
  }
  evalAll(rows, context, result);
}

// Optimization that attempts to cache results for inputs that are dictionary
// encoded and use the same base vector between subsequent input batches. Since
// this hold onto a reference to the base vector and the cached results, it can
// be memory intensive. Therefore in order to reduce this consumption and ensure
// it is only employed for cases where it can be useful, it only starts caching
// result after it encounters the same base at least twice.
void Expr::evalWithMemo(
    const SelectivityVector& rows,
    EvalCtx& context,
    VectorPtr& result) {
  VectorPtr base;
  distinctFields_[0]->evalSpecialForm(rows, context, base);

  if (base.get() != baseOfDictionaryRawPtr_ ||
      baseOfDictionaryWeakPtr_.expired()) {
    baseOfDictionaryRepeats_ = 0;
    baseOfDictionaryWeakPtr_ = base;
    baseOfDictionaryRawPtr_ = base.get();
    context.releaseVector(baseOfDictionary_);