If they are defined, they can override table-level settings.
loaded_parts.push_back(part);
    }
    return loaded_parts;
}
namespace
{
inline ReservationPtr checkAndReturnReservation(UInt64 expected_size, ReservationPtr reservation)
{
    if (reservation)
        return reservation;
    throw Exception(fmt::format("Cannot reserve {}, not enough space", ReadableSize(expected_size)), ErrorCodes::NOT_ENOUGH_SPACE);
}
}
ReservationPtr MergeTreeData::reserveSpace(UInt64 expected_size) const
{
    expected_size = std::max(RESERVATION_MIN_ESTIMATION_SIZE, expected_size);
    return getStoragePolicy()->reserveAndCheck(expected_size);
}
ReservationPtr MergeTreeData::reserveSpace(UInt64 expected_size, SpacePtr space)
{
    expected_size = std::max(RESERVATION_MIN_ESTIMATION_SIZE, expected_size);
    auto reservation = tryReserveSpace(expected_size, space);
    return checkAndReturnReservation(expected_size, std::move(reservation));
}
ReservationPtr MergeTreeData::tryReserveSpace(UInt64 expected_size, SpacePtr space)
{
    expected_size = std::max(RESERVATION_MIN_ESTIMATION_SIZE, expected_size);
    return space->reserve(expected_size);
}
ReservationPtr MergeTreeData::reserveSpacePreferringTTLRules(