Method doGetOutput

bolt/exec/MergeJoin.cpp:958–1293

    return nullptr;
  }
}

RowVectorPtr MergeJoin::doGetOutput() {
  // Check if we ran out of space in the output vector in the middle of the
  // match.
  if (leftMatch_ && leftMatch_->cursor) {
    BOLT_CHECK(rightMatch_ && rightMatch_->cursor);

    // Not all rows from the last match fit in the output. Continue producing
    // results from the current match.
    if (addToOutput()) {
      previousLeftMatch_ = leftMatch_;
      return std::move(output_);
    } else {
      previousLeftMatch_ = leftMatch_;
    }
  }

  // There is no output-in-progress match, but there could be incomplete
  // match.
  if (leftMatch_) {
    BOLT_CHECK(rightMatch_);

    if (input_) {
      // Look for continuation of a match on the left and/or right sides.
      if (!findEndOfMatch(leftMatch_.value(), input_, leftKeys_)) {
        // Continue looking for the end of the match.
        input_ = nullptr;
        return nullptr;
      }

      if (leftMatch_->inputs.back() == input_) {
        index_ = leftMatch_->endIndex;
      }
    } else if (noMoreInput_) {
      leftMatch_->complete = true;
    } else {
      // Need more input.
      return nullptr;
    }

    if (rightInput_) {
      if (!findEndOfMatch(rightMatch_.value(), rightInput_, rightKeys_)) {
        // Continue looking for the end of the match.
        rightInput_ = nullptr;
        return nullptr;
      }
      if (rightMatch_->inputs.back() == rightInput_) {
        if (isFullJoin(joinType_) || isRightJoin(joinType_)) {
          rightIndex_ = rightMatch_->endIndex;
        } else {
          rightIndex_ =
              firstNonNull(rightInput_, rightKeys_, rightMatch_->endIndex);
          if (rightIndex_ == rightInput_->size()) {
            rightInput_ = nullptr;
          }
        }