Method getDefaultGlobalGroupingSetOutput

bolt/exec/GroupingSet.cpp:663–729

}

bool GroupingSet::getDefaultGlobalGroupingSetOutput(
    RowContainerIterator& iterator,
    RowVectorPtr& result) {
  BOLT_CHECK(hasDefaultGlobalGroupingSetOutput());

  if (iterator.allocationIndex != 0) {
    return false;
  }
  // Global aggregates don't have grouping keys. But global grouping sets
  // have null values in grouping keys and a groupId column as well. These
  // key fields precede the aggregate columns in the result.
  // This logic builds a row with just aggregate fields to reuse the global
  // aggregate computation from the regular GroupingSet code-path.
  auto outputType = asRowType(result->type());
  auto firstAggregateCol = outputType->size() - aggregates_.size();
  std::vector<std::string> names;
  std::vector<TypePtr> types;
  names.reserve(aggregates_.size());
  types.reserve(aggregates_.size());
  for (auto i = firstAggregateCol; i < outputType->size(); i++) {
    names.push_back(outputType->nameOf(i));
    types.push_back(outputType->childAt(i));
  }
  auto aggregatesType = ROW(std::move(names), std::move(types));
  auto globalAggregatesRow =
      BaseVector::create<RowVector>(aggregatesType, 1, &pool_);

  BOLT_CHECK(getGlobalAggregationOutput(iterator, globalAggregatesRow));

  // There is one output row for each global GroupingSet.
  const auto numGroupingSets = globalGroupingSets_.size();
  result->resize(numGroupingSets);
  BOLT_CHECK(groupIdChannel_.has_value());
  // These first columns are for grouping keys (which could include the
  // GroupId column). For a global grouping set row :
  // i) Non-groupId grouping keys are null.
  // ii) GroupId column is populated with the global grouping set number.
  for (auto i = 0; i < firstAggregateCol; i++) {
    auto column = result->childAt(i);
    if (i == groupIdChannel_.value()) {
      column->resize(numGroupingSets);
      auto* groupIdVector = column->asFlatVector<int64_t>();
      for (auto j = 0; j < numGroupingSets; j++) {
        groupIdVector->set(j, globalGroupingSets_.at(j));
      }
    } else {
      column->resize(numGroupingSets, false);
      for (auto j = 0; j < numGroupingSets; j++) {
        column->setNull(j, true);
      }
    }
  }

  // The remaining aggregate columns are filled from the computed global
  // aggregates.
  for (auto i = firstAggregateCol; i < outputType->size(); i++) {
    auto resultAggregateColumn = result->childAt(i);
    resultAggregateColumn->resize(numGroupingSets);