message: Avoid more big objects on the stack
diff: @@ -2298,7 +2298,11 @@ private:
  template <class>
  class BacklinkCount : public Subexpr2<Int> {
  public:
  - BacklinkCount(LinkMap link_map)
  + BacklinkCount(const LinkMap& link_map)
  + : m_link_map(link_map)
  + {
  + }
  + BacklinkCount(LinkMap&& link_map)
  : m_link_map(std::move(link_map))
  {
  }
  @@ -2368,8 +2372,8 @@ public:
  }
  private:
  - const ClusterKeyArray* m_keys;
  - uint64_t m_offset;
  + const ClusterKeyArray* m_keys = nullptr;
  + uint64_t m_offset = 0;
  LinkMap m_link_map;
  };
  @@ -3148,9 +3152,9 @@ class SubColumnAggregate;
  template <typename T>
  class SubColumns : public Subexpr {
  public:
  - SubColumns(Columns<T> column, LinkMap link_map)
  + SubColumns(Columns<T>&& column, const LinkMap& link_map)
  : m_column(std::move(column))
  - , m_link_map(std::move(link_map))
  + , m_link_map(link_map)
  {
  }
  @@ -3214,9 +3218,9 @@ private:
  template <typename T, typename Operation>
  class SubColumnAggregate : public Subexpr2<typename Operation::ResultType> {
  public:
  - SubColumnAggregate(Columns<T> column, LinkMap link_map)
  - : m_column(std::move(column))
  - , m_link_map(std::move(link_map))
  + SubColumnAggregate(const Columns<T>& column, const LinkMap& link_map)
  + : m_column(column)
  + , m_link_map(link_map)
  {
  }
  SubColumnAggregate(SubColumnAggregate const& other)
  @@ -3289,9 +3293,9 @@ private:
  class SubQueryCount : public Subexpr2<Int> {
  public:
  - SubQueryCount(Query q, LinkMap link_map)
  - : m_query(std::move(q))
  - , m_link_map(std::move(link_map))
  + SubQueryCount(const Query& q, const LinkMap& link_map)
  + : m_query(q)
  + , m_link_map(link_map)
  {
  }
  