Method Fetch

src/data/sparse_page_source.h:449–470

  bst_idx_t n_batches_{0};

  void Fetch() final {
    page_ = std::make_shared<SparsePage>();
    // The first round of reading, this is responsible for initialization.
    if (!this->ReadCache()) {
      bool type_error{false};
      CHECK(proxy_);
      cpu_impl::DispatchAny(
          proxy_,
          [&](auto const& adapter_batch) {
            page_->Push(adapter_batch, this->missing_, this->nthreads_);
          },
          &type_error);
      if (type_error) {
        DevicePush(proxy_, missing_, page_.get());
      }

      page_->SetBaseRowId(base_row_id_);
      base_row_id_ += page_->Size();
      this->n_batches_++;
      this->WriteCache();
    }
  }

 public:
  SparsePageSource(DataIterProxy<DataIterResetCallback, XGDMatrixCallbackNext> iter,