Method Merge

cpp/src/parquet/statistics.cc:702–726

  }

  void Merge(const TypedStatistics<DType>& other) override {
    this->num_values_ += other.num_values();
    // null_count is always valid when merging page statistics into
    // column chunk statistics.
    if (other.HasNullCount()) {
      this->statistics_.null_count += other.null_count();
    } else {
      this->has_null_count_ = false;
    }
    if (has_distinct_count_ && other.HasDistinctCount() &&
        (distinct_count() == 0 || other.distinct_count() == 0)) {
      // We can merge distinct counts if either side is zero.
      statistics_.distinct_count =
          std::max(statistics_.distinct_count, other.distinct_count());
    } else {
      // Otherwise clear has_distinct_count_ as distinct count cannot be merged.
      this->has_distinct_count_ = false;
    }
    // Do not clear min/max here if the other side does not provide
    // min/max which may happen when other is an empty stats or all
    // its values are null and/or NaN.
    if (other.HasMinMax()) {
      SetMinMax(other.min(), other.max());
    }
  }

  void Update(const T* values, int64_t num_values, int64_t null_count) override;
  void UpdateSpaced(const T* values, const uint8_t* valid_bits, int64_t valid_bits_offset,