types::BString RCAttr::GetNotNullValueString(const int64_t obj) {
  int pack = row2pack(obj);
  int offset = row2offset(obj);

  static const types::BString void_bs;
  if (GetPackType() == common::PackType::STR) {
    auto cur_pack = get_packS(pack);

    if (!cur_pack) {
      // TIANMU_LOG(LogCtl_Level::INFO, "rc_attr:GetNotNullValueString get_packS NULL, obj: %d pack: %d offset: %d", obj,
      //            pack, offset);
      return void_bs;
    }

    uint64_t p = reinterpret_cast<uint64_t>(cur_pack);
    if (0xffffffffffff == p) {
      return void_bs;
    }

    ASSERT(cur_pack != NULL, "Pack ptr is null");
    ASSERT(cur_pack->IsLocked(), "Access unlocked pack");
    return cur_pack->GetValueBinary(offset);
  }
  int64_t v = GetNotNullValueInt64(obj);
  return DecodeValue_S(v);
}

Pack *RCAttr::get_pack(size_t i) { return reinterpret_cast<Pack *>(get_dpn(i).GetPackPtr() & tag_mask); }

DPN &get_dpn(size_t i) {
    ASSERT(i < m_idx.size(), "bad dpn index " + std::to_string(i) + "/" + std::to_string(m_idx.size()));
    return *m_share->get_dpn_ptr(m_idx[i]);
  }

DPN *get_dpn_ptr(common::PACK_INDEX i) {
    ASSERT(i < common::COL_DN_FILE_SIZE / sizeof(DPN), "bad dpn index: " + std::to_string(i));
    return &start[i];
  }

DPN *start;

uint64_t GetPackPtr() const { return tagged_ptr.load(); }

// a tagged pointer, 16 bits as ref count.
  // Only read-only dpn uses it for ref counting; local dpn is managed only by
  // one write session
  std::atomic_ulong tagged_ptr;