Replace Databuffers with TensorRows

mindspore/ccsrc/minddata/dataset/core/tensor_row.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2020 Huawei Technologies Co., Ltd
+ * Copyright 2020-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,15 +21,21 @@
 namespace mindspore {
 namespace dataset {
 
-TensorRow::TensorRow() noexcept : id_(kDefaultRowId), path_({}) {}
+TensorRow::TensorRow() noexcept : id_(kDefaultRowId), path_({}), tensor_row_flag_(kFlagNone) {}
 
-TensorRow::TensorRow(size_type n, TensorRow::value_type t) noexcept : id_(kDefaultRowId), path_({}), row_(n, t) {}
+TensorRow::TensorRow(size_type n, TensorRow::value_type t) noexcept
+    : id_(kDefaultRowId), path_({}), row_(n, t), tensor_row_flag_(kFlagNone) {}
 
-TensorRow::TensorRow(const TensorRow::vector_type &v) : id_(kDefaultRowId), path_({}), row_(v) {}
+TensorRow::TensorRow(const TensorRow::vector_type &v)
+    : id_(kDefaultRowId), path_({}), row_(v), tensor_row_flag_(kFlagNone) {}
 
-TensorRow::TensorRow(row_id_type id, const std::initializer_list<value_type> &lst) : id_(id), path_({}), row_(lst) {}
+TensorRow::TensorRow(row_id_type id, const std::initializer_list<value_type> &lst)
+    : id_(id), path_({}), row_(lst), tensor_row_flag_(kFlagNone) {}
 
-TensorRow::TensorRow(const TensorRow &tr) : id_(tr.id_), path_(tr.path_), row_(tr.row_) {}
+TensorRow::TensorRow(const TensorRow &tr)
+    : id_(tr.id_), path_(tr.path_), row_(tr.row_), tensor_row_flag_(tr.tensor_row_flag_) {}
+
+TensorRow::TensorRow(TensorRow::TensorRowFlags flag) : tensor_row_flag_(flag) {}
 
 TensorRow &TensorRow::operator=(const TensorRow &tr) {
   if (this == &tr) {
@@ -38,23 +44,27 @@ TensorRow &TensorRow::operator=(const TensorRow &tr) {
   row_ = tr.row_;
   id_ = tr.id_;
   path_ = tr.path_;
+  tensor_row_flag_ = tr.tensor_row_flag_;
   return *this;
 }
 
 TensorRow &TensorRow::operator=(const std::initializer_list<TensorRow::value_type> &lst) {
   row_ = lst;
+  tensor_row_flag_ = kFlagNone;
   return *this;
 }
 
-TensorRow::TensorRow(TensorRow::vector_type &&v) noexcept : id_(kDefaultRowId), path_({}), row_(std::move(v)) {}
+TensorRow::TensorRow(TensorRow::vector_type &&v) noexcept
+    : id_(kDefaultRowId), path_({}), row_(std::move(v)), tensor_row_flag_(kFlagNone) {}
 
 TensorRow::TensorRow(row_id_type id, std::initializer_list<value_type> &&lst) noexcept
-    : id_(id), path_({}), row_(std::move(lst)) {}
+    : id_(id), path_({}), row_(std::move(lst)), tensor_row_flag_(kFlagNone) {}
 
 TensorRow::TensorRow(TensorRow &&tr) noexcept {
   id_ = tr.id_;
   path_ = std::move(tr.path_);
   row_ = std::move(tr.row_);
+  tensor_row_flag_ = tr.tensor_row_flag_;
 }
 
 TensorRow &TensorRow::operator=(TensorRow &&tr) noexcept {
@@ -65,11 +75,13 @@ TensorRow &TensorRow::operator=(TensorRow &&tr) noexcept {
   id_ = tr.id_;
   tr.id_ = kDefaultRowId;
   path_ = std::move(tr.path_);
+  tensor_row_flag_ = tr.tensor_row_flag_;
   return *this;
 }
 
 TensorRow &TensorRow::operator=(std::initializer_list<TensorRow::value_type> &&lst) noexcept {
   row_ = std::move(lst);
+  tensor_row_flag_ = kFlagNone;
   return *this;
 }
 

mindspore/ccsrc/minddata/dataset/core/tensor_row.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2020 Huawei Technologies Co., Ltd
+ * Copyright 2020-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,6 +35,14 @@ class TensorRow {
  public:
   static constexpr row_id_type kDefaultRowId = -1;  // Default row id
 
+  enum TensorRowFlags : uint32_t {
+    kFlagNone = 0,
+    kFlagEOF = 1,         // The buffer is an eof end-of-data msg
+    kFlagEOE = 1u << 1,   // The buffer is an eoe end-of-epoch msg
+    kFlagWait = 1u << 2,  // The buffer is an control signal for workers to suspend operations
+    kFlagQuit = 1u << 3   // The buffer is a control signal for workers to quit
+  };
+
   // Type definitions
   using size_type = dsize_t;
   using value_type = std::shared_ptr<Tensor>;
@@ -222,10 +230,25 @@ class TensorRow {
 
   const_iterator end() const { return row_.end(); }
 
+  // Convenience getter functions for flag checking
+  bool eof() const { return (static_cast<uint32_t>(tensor_row_flag_) & static_cast<uint32_t>(kFlagEOF)); }
+
+  bool eoe() const { return (static_cast<uint32_t>(tensor_row_flag_) & static_cast<uint32_t>(kFlagEOE)); }
+
+  bool wait() const { return (static_cast<uint32_t>(tensor_row_flag_) & static_cast<uint32_t>(kFlagWait)); }
+
+  bool quit() const { return (static_cast<uint32_t>(tensor_row_flag_) & static_cast<uint32_t>(kFlagQuit)); }
+
+  TensorRowFlags Flags() { return tensor_row_flag_; }
+
+  explicit TensorRow(TensorRowFlags);
+
  protected:
   row_id_type id_;
   std::vector<std::string> path_;
   std::vector<std::shared_ptr<Tensor>> row_;
+
+  TensorRowFlags tensor_row_flag_;
 };
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/engine/cache/cache_client.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2020 Huawei Technologies Co., Ltd
+ * Copyright 2020-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -114,27 +114,6 @@ Status CacheClient::WriteRow(const TensorRow &row, row_id_type *row_id_from_serv
   return Status::OK();
 }
 
-Status CacheClient::WriteBuffer(std::unique_ptr<DataBuffer> &&in) const {
-  std::unique_ptr<DataBuffer> db_ptr = std::move(in);
-  auto num_rows = db_ptr->NumRows();
-  // We will send the requests async first on all rows and do a final wait.
-  if (num_rows > 0) {
-    auto arr = std::make_unique<std::shared_ptr<CacheRowRequest>[]>(num_rows);
-    for (auto i = 0; i < num_rows; ++i) {
-      TensorRow row;
-      RETURN_IF_NOT_OK(db_ptr->PopRow(&row));
-      arr[i] = std::make_shared<CacheRowRequest>(this);
-      RETURN_IF_NOT_OK(arr[i]->SerializeCacheRowRequest(this, row));
-      RETURN_IF_NOT_OK(PushRequest(arr[i]));
-    }
-    // Now we wait for them to come back
-    for (auto i = 0; i < num_rows; ++i) {
-      RETURN_IF_NOT_OK(arr[i]->Wait());
-    }
-  }
-  return Status::OK();
-}
-
 Status CacheClient::AsyncWriteRow(const TensorRow &row) {
   if (async_buffer_stream_ == nullptr) {
     return Status(StatusCode::kMDNotImplementedYet);
@@ -143,34 +122,6 @@ Status CacheClient::AsyncWriteRow(const TensorRow &row) {
   return Status::OK();
 }
 
-Status CacheClient::AsyncWriteBuffer(std::unique_ptr<DataBuffer> &&in) {
-  if (async_buffer_stream_ == nullptr) {
-    return Status(StatusCode::kMDNotImplementedYet);
-  } else {
-    Status rc;
-    std::unique_ptr<TensorQTable> tensor_table = std::make_unique<TensorQTable>();
-    auto num_rows = in->NumRows();
-    if (num_rows > 0) {
-      for (auto i = 0; i < num_rows; ++i) {
-        TensorRow row;
-        RETURN_IF_NOT_OK(in->PopRow(&row));
-        rc = AsyncWriteRow(row);
-        if (rc.StatusCode() == StatusCode::kMDNotImplementedYet) {
-          tensor_table->push_back(row);
-        } else if (rc.IsError()) {
-          return rc;
-        }
-      }
-    }
-    // If not all of them can be sent async, return what's left back to the caller.
-    if (!tensor_table->empty()) {
-      in->set_tensor_table(std::move(tensor_table));
-      return Status(StatusCode::kMDNotImplementedYet);
-    }
-  }
-  return Status::OK();
-}
-
 Status CacheClient::GetRows(const std::vector<row_id_type> &row_id, TensorTable *out) const {
   RETURN_UNEXPECTED_IF_NULL(out);
   auto rq = std::make_shared<BatchFetchRequest>(this, row_id);

mindspore/ccsrc/minddata/dataset/engine/cache/cache_client.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2020 Huawei Technologies Co., Ltd
+ * Copyright 2020-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -156,11 +156,6 @@ class CacheClient {
   /// \return return code
   Status WriteRow(const TensorRow &row, row_id_type *row_id_from_server = nullptr) const;
 
-  /// \brief Send a DataBuffer to the cache server
-  /// \param in Unique pointer of the DataBuffer to be cached
-  /// \return return code
-  Status WriteBuffer(std::unique_ptr<DataBuffer> &&in) const;
-
   /// \brief Fetch a list of rows from the cache server. An empty TensorRow will be returned if there is
   /// any cache miss
   /// \param row_id A vector of row id's
@@ -257,6 +252,9 @@ class CacheClient {
     return false;
   }
 
+  /// \brief Serialize a Tensor into the async buffer.
+  Status AsyncWriteRow(const TensorRow &row);
+
   // Default size of the async write buffer
   constexpr static int64_t kAsyncBufferSize = 16 * 1048576L;  // 16M
   constexpr static int32_t kNumAsyncBuffer = 3;
@@ -269,8 +267,6 @@ class CacheClient {
     return Status::OK();
   }
 
-  Status AsyncWriteBuffer(std::unique_ptr<DataBuffer> &&in);
-
  private:
   mutable RWLock mux_;
   uint64_t cache_mem_sz_;
@@ -354,9 +350,6 @@ class CacheClient {
     std::atomic<int64_t> next_addr_;
   };
   std::shared_ptr<AsyncBufferStream> async_buffer_stream_;
-
-  /// \brief Serialize a Tensor into the async buffer.
-  Status AsyncWriteRow(const TensorRow &row);
 };
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/engine/cache/perf/cache_pipeline_run.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2020 Huawei Technologies Co., Ltd
+ * Copyright 2020-2021 Huawei Technologies Co., Ltd
 
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -272,7 +272,6 @@ Status CachePipelineRun::WriterWorkerEntry(int32_t worker_id) {
   int64_t min_val = std::numeric_limits<int64_t>::max();
   int64_t max_val = 0;
   int64_t total_val = 0;
-  int64_t cnt = 0;
   std::vector<int64_t> duration;
   duration.reserve(num_rows_ / num_pipelines_ / cfg_.num_parallel_workers());
   bool resource_err = false;
@@ -291,8 +290,6 @@ Status CachePipelineRun::WriterWorkerEntry(int32_t worker_id) {
     }
     // Once we hit resource error, we drain the io block. No point to send anything to the server.
     if (!resource_err) {
-      auto buffer = std::make_unique<DataBuffer>(cnt++, DataBuffer::kDeBFlagNone);
-      auto tensor_table = std::make_unique<TensorQTable>();
       for (auto id : keys) {
         TensorRow row;
         std::shared_ptr<Tensor> element;
@@ -305,29 +302,27 @@ Status CachePipelineRun::WriterWorkerEntry(int32_t worker_id) {
           *it = i;
         }
         row.push_back(std::move(element));
-        tensor_table->push_back(std::move(row));
-      }
-      buffer->set_tensor_table(std::move(tensor_table));
-      // Measure the time to call WriteBuffer
-      auto start_tick = std::chrono::steady_clock::now();
-      rc = cc_->AsyncWriteBuffer(std::move(buffer));
-      auto end_tick = std::chrono::steady_clock::now();
-      if (rc.IsError()) {
-        if (rc == StatusCode::kMDOutOfMemory || rc == StatusCode::kMDNoSpace) {
-          MS_LOG(WARNING) << "Pipeline number " << my_pipeline_ + 1 << " worker id " << worker_id << ": "
-                          << rc.ToString();
-          resource_err = true;
-          cc_->ServerRunningOutOfResources();
-          continue;
+        // Measure the time to call WriteBuffer
+        auto start_tick = std::chrono::steady_clock::now();
+        rc = cc_->AsyncWriteRow(std::move(row));
+        auto end_tick = std::chrono::steady_clock::now();
+        if (rc.IsError()) {
+          if (rc == StatusCode::kMDOutOfMemory || rc == StatusCode::kMDNoSpace) {
+            MS_LOG(WARNING) << "Pipeline number " << my_pipeline_ + 1 << " worker id " << worker_id << ": "
+                            << rc.ToString();
+            resource_err = true;
+            cc_->ServerRunningOutOfResources();
+            continue;
+          } else {
+            return rc;
+          }
         } else {
-          return rc;
+          int64_t ms = std::chrono::duration_cast<std::chrono::microseconds>(end_tick - start_tick).count();
+          min_val = std::min(min_val, ms);
+          max_val = std::max(max_val, ms);
+          duration.push_back(ms);
+          total_val += ms;
         }
-      } else {
-        int64_t ms = std::chrono::duration_cast<std::chrono::microseconds>(end_tick - start_tick).count();
-        min_val = std::min(min_val, ms);
-        max_val = std::max(max_val, ms);
-        duration.push_back(ms);
-        total_val += ms;
       }
     }
   } while (true);

mindspore/ccsrc/minddata/dataset/engine/dataset_iterator.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2019 Huawei Technologies Co., Ltd
+ * Copyright 2019-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,13 +27,9 @@
 
 namespace mindspore {
 namespace dataset {
-// Constructor of the IteratorBase
-IteratorBase::IteratorBase() : curr_buffer_(nullptr), eof_handled_(false) {}
-
-IteratorBase::~IteratorBase() = default;
 
 // Fetches one row of data from the iterator as a column map.
-Status IteratorBase::GetNextAsMap(TensorMap *out_map) {
+Status DatasetIterator::GetNextAsMap(TensorMap *out_map) {
   if (out_map == nullptr) {
     RETURN_STATUS_UNEXPECTED("Null output map in iterator!");
   }
@@ -67,63 +63,14 @@ Status IteratorBase::GetNextAsMap(TensorMap *out_map) {
 
   return Status::OK();
 }
-
-// Fetches one row of data from the iterator.
-// The base class version simply performs error handling and returns empty row. Actual
-// functionality exists in the derived versions of this function.
-Status IteratorBase::FetchNextTensorRow(TensorRow *out_row) {
-  if (out_row == nullptr) {
-    RETURN_STATUS_UNEXPECTED("Null output row in iterator!");
-  }
-
-  // clear the old tensor row
-  out_row->clear();
-
-  return Status::OK();
-}
-
-Status IteratorBase::GetNextAsOrderedPair(std::vector<std::pair<std::string, std::shared_ptr<Tensor>>> *vec) {
-  CHECK_FAIL_RETURN_UNEXPECTED(vec != nullptr && vec->empty(), "vec is null or non-empty.");
-
-  TensorRow curr_row;
-
-  RETURN_IF_NOT_OK(FetchNextTensorRow(&curr_row));
-  RETURN_OK_IF_TRUE(curr_row.empty());
-
-  size_t num_cols = curr_row.size();  // num_cols is non-empty.
-  if (col_name_id_map_.empty()) col_name_id_map_ = this->GetColumnNameMap();
-  // order the column names according to their ids
-  if (column_order_.empty()) {
-    const int32_t invalid_col_id = -1;
-    column_order_.resize(num_cols, {std::string(), invalid_col_id});
-    for (const auto &itr : col_name_id_map_) {
-      int32_t ind = itr.second;
-      CHECK_FAIL_RETURN_UNEXPECTED(ind < num_cols && ind >= 0, "column id out of bounds.");
-      column_order_[ind] = std::make_pair(itr.first, ind);
-    }
-    // error check, make sure the ids in col_name_id_map are continuous and starts from 0
-    for (const auto &col : column_order_) {
-      CHECK_FAIL_RETURN_UNEXPECTED(col.second != invalid_col_id, "column ids are not continuous.");
-    }
-  }
-
-  vec->reserve(num_cols);
-
-  for (const auto &col : column_order_) {
-    vec->emplace_back(std::make_pair(col.first, curr_row[col.second]));
-  }
-
-  return Status::OK();
-}
-
 // Constructor of the DatasetIterator
 DatasetIterator::DatasetIterator(std::shared_ptr<ExecutionTree> exe_tree)
-    : IteratorBase(),
-      root_(exe_tree->root()),
+    : root_(exe_tree->root()),
       tracing_(nullptr),
       cur_batch_num_(0),
       cur_connector_size_(0),
-      cur_connector_capacity_(0) {
+      cur_connector_capacity_(0),
+      eof_handled_(false) {
   std::shared_ptr<Tracing> node;
   Status s = exe_tree->GetProfilingManager()->GetTracingNode(kDatasetIteratorTracingName, &node);
   if (s.IsOk()) {
@@ -136,8 +83,11 @@ DatasetIterator::~DatasetIterator() = default;
 // Fetches one row of data from the iterator.  Overrides the base class.  This one fetches
 // from the tree root node directly.
 Status DatasetIterator::FetchNextTensorRow(TensorRow *out_row) {
-  // Common code init and error checking in the base class.
-  RETURN_IF_NOT_OK(IteratorBase::FetchNextTensorRow(out_row));
+  if (out_row == nullptr) {
+    RETURN_STATUS_UNEXPECTED("Null output row in iterator!");
+  }
+  // clear the old tensor row
+  out_row->clear();
 
   bool isProfilingEnable = root_->Tree()->GetProfilingManager()->IsProfilingEnable();
 
@@ -149,41 +99,36 @@ Status DatasetIterator::FetchNextTensorRow(TensorRow *out_row) {
   }
 
   // Check if we need to get a new DataBuffer to iterate.
-  if (curr_buffer_ == nullptr || curr_buffer_->NumRows() == 0) {
-    if (tracing_ != nullptr) {
-      cur_connector_size_ = root_->ConnectorSize();
-      cur_connector_capacity_ = root_->ConnectorCapacity();
-    }
-    RETURN_IF_NOT_OK(root_->GetNextBuffer(&curr_buffer_));
 
-    // Since GetNextBuffer was used rather than GetNextInput(), it means we need to manually
-    // handle eoe and eof messages here.
-    //
-    // An eoe buffer means we have iterated an epoch.
-    // The next buffer in the pipeline might be an EOF or a databuffer for next epoch
-    if (curr_buffer_->eoe()) {
-      MS_LOG(INFO) << "End of data iteration.";
-      curr_buffer_.reset();  // explicitly free the eoe buffer
-      if (isProfilingEnable) {
-        root_->Tree()->SetEpochEnd();
-      }
-      return Status::OK();
+  if (tracing_ != nullptr) {
+    cur_connector_size_ = root_->ConnectorSize();
+    cur_connector_capacity_ = root_->ConnectorCapacity();
+  }
+  RETURN_IF_NOT_OK(root_->GetNextRow(out_row));
+
+  // Since GetNextBuffer was used rather than GetNextInput(), it means we need to manually
+  // handle eoe and eof messages here.
+  //
+  // An eoe buffer means we have iterated an epoch.
+  // The next buffer in the pipeline might be an EOF or a databuffer for next epoch
+  if (out_row->eoe()) {
+    MS_LOG(INFO) << "End of data iteration.";
+    if (isProfilingEnable) {
+      root_->Tree()->SetEpochEnd();
     }
+    return Status::OK();
+  }
 
-    // An eof buffer means it is the end of execution and all operators are shutting down.
-    // Because there is no more data to return to the caller, this will change `eof_handled_` state and
-    // returns status unexpected error.
-    if (curr_buffer_->eof()) {
-      eof_handled_ = true;
-      curr_buffer_.reset();  // explicitly free the eof buffer
-      root_->Tree()->SetFinished();
-      std::string err = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs.";
-      RETURN_STATUS_UNEXPECTED(err);
-    }
+  // An eof buffer means it is the end of execution and all operators are shutting down.
+  // Because there is no more data to return to the caller, this will change `eof_handled_` state and
+  // returns status unexpected error.
+  if (out_row->eof()) {
+    eof_handled_ = true;
+    root_->Tree()->SetFinished();
+    std::string err = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs.";
+    RETURN_STATUS_UNEXPECTED(err);
   }
 
-  // If we got this far, now it's time to pop that next row for return to caller
-  RETURN_IF_NOT_OK(curr_buffer_->PopRow(out_row));
   if (tracing_ != nullptr) {
     cur_batch_num_++;
     tracing_->Record(CONNECTOR_DEPTH, cur_connector_capacity_, cur_batch_num_, cur_connector_size_,
@@ -192,33 +137,6 @@ Status DatasetIterator::FetchNextTensorRow(TensorRow *out_row) {
   return Status::OK();
 }
 
-Status DatasetIterator::GetOutputShapes(std::vector<TensorShape> *out_shapes) {
-  if (out_shapes == nullptr) {
-    RETURN_STATUS_UNEXPECTED("Null output shape argument");
-  }
-  if (device_queue_row_.empty()) {
-    RETURN_IF_NOT_OK(FetchNextTensorRow(&device_queue_row_));
-  }
-  for (const auto ts : device_queue_row_) {
-    out_shapes->push_back(ts->shape());
-  }
-
-  return Status::OK();
-}
-
-Status DatasetIterator::GetOutputTypes(std::vector<DataType> *out_types) {
-  if (out_types == nullptr) {
-    RETURN_STATUS_UNEXPECTED("Null output type argument");
-  }
-  if (device_queue_row_.empty()) {
-    RETURN_IF_NOT_OK(FetchNextTensorRow(&device_queue_row_));
-  }
-  for (const auto ts : device_queue_row_) {
-    out_types->push_back(ts->type());
-  }
-  return Status::OK();
-}
-
 // Getter
 std::unordered_map<std::string, int32_t> DatasetIterator::GetColumnNameMap() const {
   return root_->column_name_id_map();
@@ -226,15 +144,16 @@ std::unordered_map<std::string, int32_t> DatasetIterator::GetColumnNameMap() con
 
 // Constructor of the ChildIterator
 ChildIterator::ChildIterator(DatasetOp *current_op, int32_t worker_id, int32_t child_idx)
-    : IteratorBase(), current_op_(current_op), child_idx_(child_idx), worker_id_(worker_id), end_epoch_(false) {}
+    : current_op_(current_op), child_idx_(child_idx), worker_id_(worker_id), end_epoch_(false), eof_handled_(false) {}
 
 ChildIterator::~ChildIterator() { current_op_ = nullptr; }
 
 // Fetches one row of data from the iterator.  Overrides the base class.  This one fetches
 // only from the child/worker id as given from the constructor.
 Status ChildIterator::FetchNextTensorRow(TensorRow *out_row) {
-  // Common code init and error checking in the base class.
-  RETURN_IF_NOT_OK(IteratorBase::FetchNextTensorRow(out_row));
+  RETURN_UNEXPECTED_IF_NULL(out_row);
+  // clear the old tensor row
+  out_row->clear();
 
   // Once eof is handled, always return empty row.  Class must be destroyed and recreated if you
   // want to iterate again.
@@ -243,32 +162,24 @@ Status ChildIterator::FetchNextTensorRow(TensorRow *out_row) {
     RETURN_STATUS_UNEXPECTED(err);
   }
 
-  // Check if we need to get a new DataBuffer to iterate.
-  if (curr_buffer_ == nullptr || curr_buffer_->NumRows() == 0) {
-    // GetNextInput() depends on current_op's EoeReceived. So, EOE buffer might be already be handled and
-    // this child iterator might not see EOE buffer.
-    RETURN_IF_NOT_OK(current_op_->GetNextInput(&curr_buffer_, worker_id_, child_idx_));
-
-    // If an eoe is picked up here, we simply return an empty vector and it's up to the
-    // caller to decide what it wants to do next.
-    if (curr_buffer_->eoe()) {
-      MS_LOG(DEBUG) << "Child iterator picked up EOE.";
-      end_epoch_ = true;
-      return Status::OK();
-    } else {
-      end_epoch_ = false;
-    }
-
-    if (curr_buffer_->eof()) {
-      MS_LOG(DEBUG) << "Child iterator picked up EOF.";
-      eof_handled_ = true;
-      return Status::OK();
-    }
+  RETURN_IF_NOT_OK(current_op_->child(child_idx_)->GetNextRow(out_row, worker_id_));
+  // If an eoe is picked up here, we simply return an empty vector and it's up to the
+  // caller to decide what it wants to do next.TensorRow
+  if (out_row->eoe()) {
+    MS_LOG(DEBUG) << "(" << current_op_->NameWithID() << ", " << child_idx_ << ")"
+                  << "Child iterator picked up EOE.";
+    end_epoch_ = true;
+    return Status::OK();
+  } else {
+    end_epoch_ = false;
   }
 
-  // If we got this far, now it's time to pop that next row for return to caller
-  RETURN_IF_NOT_OK(curr_buffer_->PopRow(out_row));
-
+  if (out_row->eof()) {
+    MS_LOG(DEBUG) << "(" << current_op_->NameWithID() << ", " << child_idx_ << ")"
+                  << "Child iterator picked up EOF.";
+    eof_handled_ = true;
+    *out_row = TensorRow(TensorRow::kFlagEOF);
+  }
   return Status::OK();
 }
 
@@ -285,11 +196,12 @@ Status ChildIterator::Drain() {
     return Status::OK();
   }
   MS_LOG(DEBUG) << "Child draining buffers until eoe.";
+  TensorRow row;
   // else we drain until eoe or eof, eof here is for sanity check
-  while (!curr_buffer_->eoe() && !curr_buffer_->eof()) {
-    RETURN_IF_NOT_OK(current_op_->GetNextInput(&curr_buffer_, worker_id_, child_idx_));
+  while (!row.eoe() && !row.eof()) {
+    RETURN_IF_NOT_OK(current_op_->child(child_idx_)->GetNextRow(&row, worker_id_));
   }
-  if (curr_buffer_->eof()) {
+  if (row.eof()) {
     return Status(StatusCode::kMDUnexpectedError, __LINE__, __FILE__, "Child iterator picked up EOF in drain.");
   }
   return Status::OK();

mindspore/ccsrc/minddata/dataset/engine/dataset_iterator.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2019 Huawei Technologies Co., Ltd
+ * Copyright 2019-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,18 +35,21 @@ using TensorMap = std::unordered_map<std::string, std::shared_ptr<Tensor>>;
 // forward declare
 class ExecutionTree;
 
-class DataBuffer;
-
-// IteratorBase class is used to iterate data from an executionTree one row at a time.
-// The base class provides the general interface, whereas derived classes provide slightly
-// different implementations.
-class IteratorBase {
+// The DatasetIterator derived class is for fetching rows off the end/root of the execution tree.
+class DatasetIterator {
  public:
-  // Constructor of IteratorBase
-  IteratorBase();
+  // Constructor of the DatasetIterator
+  // @param exe_tree The execution tree we want to pull/iterate the data from using it's root node.
+  explicit DatasetIterator(std::shared_ptr<ExecutionTree> exe_tree);
 
   // Destructor
-  virtual ~IteratorBase();
+  ~DatasetIterator();
+
+  // Getter
+  // @return The string to column id mapping.
+  std::unordered_map<std::string, int32_t> GetColumnNameMap() const;
+
+  bool eof_handled() const { return eof_handled_; }
 
   // Fetches one row of data from the iterator.
   // the base class version simply performs error handling and returns empty row. Actual
@@ -57,63 +60,12 @@ class IteratorBase {
   // @note The position of a Tensor/column might be different from the initial column order
   // in corresponding Dataset Op. User must be aware that MapOp, ZipOps, and others might change
   // the column ordering.
-  virtual Status FetchNextTensorRow(TensorRow *out_row);
+  Status FetchNextTensorRow(TensorRow *out_row);
 
   // Fetches one row of data from the iterator as a column map.
   // @return A unordered map from column name to shared pointer to Tensor.
   Status GetNextAsMap(TensorMap *out_map);
 
-  /// \brief return column_name, tensor pair in the order of its column id.
-  /// \param[out] vec
-  /// \return Error code
-  Status GetNextAsOrderedPair(std::vector<std::pair<std::string, std::shared_ptr<Tensor>>> *vec);
-
-  // Getter
-  // @return T/F if this iterator is completely done after getting an eof
-  bool eof_handled() const { return eof_handled_; }
-
-  // Getter
-  // @return The string to column id mapping.
-  virtual std::unordered_map<std::string, int32_t> GetColumnNameMap() const = 0;
-
- protected:
-  std::unique_ptr<DataBuffer> curr_buffer_;  // holds the current buffer
-  bool eof_handled_;                         // T/F if this op got an eof
-  std::unordered_map<std::string, int32_t> col_name_id_map_;
-  std::vector<std::pair<std::string, int32_t>> column_order_;  // key: column name, val: column id
-};
-
-// The DatasetIterator derived class is for fetching rows off the end/root of the execution tree.
-class DatasetIterator : public IteratorBase {
- public:
-  // Constructor of the DatasetIterator
-  // @param exe_tree The execution tree we want to pull/iterate the data from using it's root node.
-  explicit DatasetIterator(std::shared_ptr<ExecutionTree> exe_tree);
-
-  // Destructor
-  ~DatasetIterator();
-
-  // Fetches one row of data from the iterator.  Overrides the base class.  This one fetches
-  // from the tree root node directly.
-  // @param out_row - A TensorRow (vector of shared pointers to Tensors).  If any of the of data
-  // messages are encountered (such as eoe or eof), then an empty TensorRow is returned back.
-  // @return Status The status code returned
-  Status FetchNextTensorRow(TensorRow *out_row) override;
-
-  // Fetches the next tensor row into device row, and returns it's shape.
-  // @param out_shapes - A vector of tensor shapes (one shape per column)
-  // @return Status The status code returned
-  Status GetOutputShapes(std::vector<TensorShape> *out_shapes);
-
-  // Fetches the next tensor row into device row, and returns it's shape.
-  // @param outShapes - A vector of tensor shapes (one shape per column)
-  // @return Status The status code returned
-  Status GetOutputTypes(std::vector<DataType> *out_types);
-
-  // Getter
-  // @return The string to column id mapping.
-  std::unordered_map<std::string, int32_t> GetColumnNameMap() const override;
-
  private:
   std::shared_ptr<DatasetOp> root_;  // saves the root of the executionTree
   TensorRow device_queue_row_;
@@ -121,11 +73,14 @@ class DatasetIterator : public IteratorBase {
   int32_t cur_batch_num_;                            // current batch number,used for profiling
   int32_t cur_connector_size_;                       // current connector size of root op,used for profiling
   int32_t cur_connector_capacity_;                   // current connector capacity of root op, used for profiling
+  bool eof_handled_;                                 // T/F if this op got an eof
+  std::unordered_map<std::string, int32_t> col_name_id_map_;
+  std::vector<std::pair<std::string, int32_t>> column_order_;  // key: column name, val: column id
 };
 
 // The ChildIterator derived class is for fetching rows from intermediate nodes of execution tree.
 // This one should only be used by internal Dataset operators, rather than an end-user.
-class ChildIterator : public IteratorBase {
+class ChildIterator {
  public:
   // Constructor of the DatasetIterator
   // @param current_op - The parent op from which we'll fetch from it's children.
@@ -141,7 +96,7 @@ class ChildIterator : public IteratorBase {
   // @param out_row - A TensorRow (vector of shared pointers to Tensors).  If any of the of data
   // messages are encountered (such as eoe or eof), then an empty TensorRow is returned back.
   // @return Status The status code returned
-  Status FetchNextTensorRow(TensorRow *out_row) override;
+  Status FetchNextTensorRow(TensorRow *out_row);
 
   // This function drains buffer until next eoe has been received.
   // It will be a no-op if the previous row returned is empty.
@@ -150,16 +105,21 @@ class ChildIterator : public IteratorBase {
 
   // Getter
   // @return The string to column id mapping.
-  std::unordered_map<std::string, int32_t> GetColumnNameMap() const override;
+  std::unordered_map<std::string, int32_t> GetColumnNameMap() const;
 
   // Return T/F if end of epoch
   bool end_of_epoch() { return end_epoch_; }
 
+  // Getter
+  // @return T/F if this iterator is completely done after getting an eof
+  bool eof_handled() const { return eof_handled_; }
+
  private:
   DatasetOp *current_op_;  // The parent operator. We consume from it's children.
   int32_t child_idx_;      // The specific child this iterator will fetch from.
   int32_t worker_id_;      // The worker id uses for fetching the child data.
   bool end_epoch_;         // the flag used when an empty row has been returned.
+  bool eof_handled_;       // T/F if this op got an eof
 };
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/engine/datasetops/barrier_op.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2020 Huawei Technologies Co., Ltd
+ * Copyright 2020-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -71,9 +71,10 @@ Status BarrierOp::operator()() {
 
   // Loop until eof is true
   while (!eof_) {
-    // Create new table to put the new tensor rows
-    std::unique_ptr<TensorQTable> curr_table = std::make_unique<TensorQTable>();
-    RETURN_IF_NOT_OK(prepare(curr_table.get()));
+    RETURN_IF_NOT_OK(prepare());
+    // read the first row
+    TensorRow new_row;
+    RETURN_IF_NOT_OK(getNextTensorRow(&new_row));
 
     // If an eof got picked up during the above prepare, then we're done
     if (eof_) {
@@ -82,92 +83,36 @@ Status BarrierOp::operator()() {
 
     // we have to output new buffer with possibly different buffer size, possibly one row
     while (!clean_up_) {
-      // 1. If a previous loop iteration sent the current table out, then create a new one.
-
-      if (curr_table == nullptr) {
-        curr_table = std::make_unique<TensorQTable>();
-      }
+      // 2 Block
+      RETURN_IF_NOT_OK(blockCond());
 
-      // 2 fill the table.  Note: clean_up mode might get turned on if epoch is finished
-      RETURN_IF_NOT_OK(fillBuffer(curr_table.get()));
-
-      // 3 create and update buffer and send it to the out connector
-      if (!curr_table->empty()) {
-        std::unique_ptr<DataBuffer> curr_buffer = std::make_unique<DataBuffer>(buffer_id_, DataBuffer::kDeBFlagNone);
-        curr_buffer->set_tensor_table(std::move(curr_table));
-        MS_LOG(DEBUG) << "Barrier operator finished one buffer, pushing, rows " << curr_buffer->NumRows() << ", cols "
-                      << curr_buffer->NumCols() << ", map " << column_name_id_map_.size() << ".";
-        RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(curr_buffer)));
-        buffer_id_++;
-      }
+      MS_LOG(DEBUG) << "Barrier operator finished one row, pushing, cols " << new_row.size() << ", map "
+                    << column_name_id_map_.size() << ".";
+      RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row)));
+      RETURN_IF_NOT_OK(getNextTensorRow(&new_row));
     }
 
-    // 4 handle drain state.
     if (clean_up_) {
       MS_LOG(DEBUG) << "Barrier operator sending epoch ending signal.";
-      // Send the eoe up.
-      RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE))));
+      // 3 Send the eoe up.
+      RETURN_IF_NOT_OK(out_connector_->SendEOE());
     }
   }
-  // 5 handle eof
+  // 4 handle eof
   // propagate eof here.
   MS_LOG(INFO) << "Barrier operator got EOF, propagating.";
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF))));
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
   return Status::OK();
 }
 
 // Handles preprocessing of the main loop, used when starting new epoch
-Status BarrierOp::prepare(TensorQTable *const table) {
+Status BarrierOp::prepare() {
   MS_LOG(DEBUG) << "Barrier operator prepares for new epoch.";
   clean_up_ = false;
-  buffer_id_ = 0;
-  if (table == nullptr) {
-    return Status(StatusCode::kMDUnexpectedError, __LINE__, __FILE__,
-                  "BarrierOp prepare phase requires a tensor table.");
-  }
-  // fill initial row
-  TensorRow new_row = {};
-  // use iterator to get next row and invoke pyfunc wait
-  RETURN_IF_NOT_OK(getNextTensorRow(&new_row));
-
-  // If the first row fetching resulted in eof, then we are done.
-  if (eof_) {
-    return Status::OK();
-  }
-  if (new_row.empty()) {
-    // This epoch is empty
-    return Status::OK();
-  }
-  // Pack this first row into our tensor table
-  // first row we also have to check if we should block
-  RETURN_IF_NOT_OK(blockCond());
-
-  table->push_back(std::move(new_row));
-
   // the update code below shouldn't do anything bad if the column name already exists.
   return Status::OK();
 }
 
-// fillBuffer always expects a new table to fill
-Status BarrierOp::fillBuffer(TensorQTable *const table) {
-  if (table == nullptr) {
-    return Status(StatusCode::kMDUnexpectedError, __LINE__, __FILE__, "BarrierOp fillBuffer null table pointer.");
-  }
-  TensorRow new_row = {};
-  while (table->size() < static_cast<size_t>(rows_per_buffer_)) {
-    RETURN_IF_NOT_OK(getNextTensorRow(&new_row));
-    // Early exit the loop if we got empty row from any of our child iterations
-    if (new_row.empty()) {
-      return Status::OK();
-    }
-    // else we got a row so pack it into the tensor table.
-    RETURN_IF_NOT_OK(blockCond());
-
-    table->push_back(std::move(new_row));
-  }
-  return Status::OK();
-}
-
 // function executes a py_func and blocks until condition becomes true.
 Status BarrierOp::blockCond() {
   {

mindspore/ccsrc/minddata/dataset/engine/datasetops/barrier_op.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2020 Huawei Technologies Co., Ltd
+ * Copyright 2020-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -139,7 +139,7 @@ class BarrierOp : public PipelineOp {
 
   // Handles preprocessing of the main loop, used when starting new epoch
   // @param table - a table of tensors to be moved into a buffer
-  Status prepare(TensorQTable *const table);
+  Status prepare();
 
   // This function calls takes a table repeatedly adds rows to it.
   // @param table - a table of tensors to be moved into a buffer
@@ -152,7 +152,7 @@ class BarrierOp : public PipelineOp {
   Status blockCond();
 
  private:
-  // clean up variable to return imcomplete buffer
+  // clean up variable to return incomplete buffer
   bool clean_up_;
   // end of file state, we stop reading data and shut down
   bool eof_;

mindspore/ccsrc/minddata/dataset/engine/datasetops/batch_op.cc

@@ -182,24 +182,21 @@ void BatchOp::Print(std::ostream &out, bool show_all) const {
   }
 }
 
-Status BatchOp::BatchRows(const std::unique_ptr<TensorQTable> *src, const std::unique_ptr<TensorQTable> *dest,
-                          dsize_t batch_size) {
+Status BatchOp::BatchRows(const std::unique_ptr<TensorQTable> *src, TensorRow *dest, dsize_t batch_size) {
   if ((*src)->size() != batch_size) {
     RETURN_STATUS_UNEXPECTED("[Internal Batch ERROR] Source table size does not match the batch_size");
   }
 
   if (batch_size == 1) {
-    TensorRow row = std::move((*src)->front());
-    row.setPath({});
+    *dest = std::move((*src)->front());
     (*src)->pop_front();
-    (*dest)->push_back(row);
-    for (const auto &tensor : (*dest)->front()) {
+
+    for (const auto &tensor : (*dest)) {
       RETURN_IF_NOT_OK(tensor->ExpandDim(0));
     }
     return Status::OK();
   }
 
-  TensorRow batched_row;
   auto num_columns = (*src)->front().size();
   for (size_t i = 0; i < num_columns; i++) {
     std::shared_ptr<Tensor> first_tensor = (*src)->at(0).at(i);  // first row, column i
@@ -234,11 +231,9 @@ Status BatchOp::BatchRows(const std::unique_ptr<TensorQTable> *src, const std::u
       }
       RETURN_IF_NOT_OK(Tensor::CreateFromVector(strings, new_shape, &new_tensor));
     }
-    batched_row.emplace_back(new_tensor);
+    dest->emplace_back(new_tensor);
   }
 
-  (*dest)->emplace_back(batched_row);
-
   return Status::OK();
 }
 
@@ -248,30 +243,26 @@ Status BatchOp::WorkerEntry(int32_t workerId) {
   RETURN_IF_NOT_OK(worker_queues_[workerId]->PopFront(&table_pair));
   while (table_pair.second.ctrl_ != batchCtrl::kQuit) {
     if (table_pair.second.ctrl_ == batchCtrl::kEOE) {
-      RETURN_IF_NOT_OK(out_connector_->Add(workerId, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE)));
+      RETURN_IF_NOT_OK(out_connector_->SendEOE(workerId));
     } else if (table_pair.second.ctrl_ == batchCtrl::kEOF) {
-      RETURN_IF_NOT_OK(out_connector_->Add(workerId, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF)));
+      RETURN_IF_NOT_OK(out_connector_->SendEOF(workerId));
     } else if (table_pair.second.ctrl_ == batchCtrl::kNoCtrl) {
-      std::unique_ptr<DataBuffer> db = nullptr;
-      RETURN_IF_NOT_OK(MakeBatchedBuffer(std::move(table_pair), &db));
-      RETURN_IF_NOT_OK(out_connector_->Add(workerId, std::move(db)));
+      TensorRow new_row;
+      RETURN_IF_NOT_OK(MakeBatchedBuffer(std::move(table_pair), &new_row));
+      RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row), workerId));
     }
     RETURN_IF_NOT_OK(worker_queues_[workerId]->PopFront(&table_pair));
   }
   return Status::OK();
 }
 
-Status BatchOp::MakeBatchedBuffer(std::pair<std::unique_ptr<TensorQTable>, CBatchInfo> table_pair,
-                                  std::unique_ptr<DataBuffer> *db) {
+Status BatchOp::MakeBatchedBuffer(std::pair<std::unique_ptr<TensorQTable>, CBatchInfo> table_pair, TensorRow *new_row) {
   RETURN_UNEXPECTED_IF_NULL(table_pair.first);
 #ifdef ENABLE_PYTHON
   if (!in_col_names_.empty()) RETURN_IF_NOT_OK(MapColumns(&table_pair));  // pass it through pyfunc
 #endif
   if (pad_) RETURN_IF_NOT_OK(PadColumns(&table_pair.first, pad_info_, column_name_id_map_));  // do padding if needed
-  (*db) = std::make_unique<DataBuffer>(table_pair.second.batch_num_, DataBuffer::kDeBFlagNone);
-  std::unique_ptr<TensorQTable> dest_table = std::make_unique<TensorQTable>();
-  RETURN_IF_NOT_OK(BatchRows(&table_pair.first, &dest_table, table_pair.first->size()));
-  (*db)->set_tensor_table(std::move(dest_table));
+  RETURN_IF_NOT_OK(BatchRows(&table_pair.first, new_row, table_pair.first->size()));
   return Status::OK();
 }
 
@@ -575,14 +566,14 @@ int64_t BatchOp::GetTreeBatchSize() {
   return start_batch_size_;
 }
 
-Status BatchOp::GetNextRow(TensorRow *row) {
+Status BatchOp::GetNextRowPullMode(TensorRow *row) {
   std::unique_ptr<TensorQTable> table = std::make_unique<TensorQTable>();
   child_iterator_ = std::make_unique<ChildIterator>(this, 0, 0);
   int32_t cur_batch_size = 0;
   RETURN_IF_NOT_OK(GetBatchSize(&cur_batch_size, CBatchInfo(0, batch_num_, batch_cnt_)));
   for (int i = 0; i < cur_batch_size; i++) {
     TensorRow new_row;
-    RETURN_IF_NOT_OK(child_[0]->GetNextRow(&new_row));
+    RETURN_IF_NOT_OK(child_[0]->GetNextRowPullMode(&new_row));
     if (!new_row.empty()) {
       table->emplace_back(new_row);
       if (table->size() == static_cast<size_t>(cur_batch_size)) break;
@@ -592,13 +583,10 @@ Status BatchOp::GetNextRow(TensorRow *row) {
       }
     }
   }
-  std::unique_ptr<TensorQTable> out = std::make_unique<TensorQTable>();
   RETURN_UNEXPECTED_IF_NULL(table);
   if (pad_) RETURN_IF_NOT_OK(PadColumns(&table, pad_info_, column_name_id_map_));  // do padding if needed
   if (!table->empty()) {
-    RETURN_IF_NOT_OK(BatchRows(&table, &out, table->size()));
-    CHECK_FAIL_RETURN_UNEXPECTED(out->size() == 1, "Batch returned 2 rows while 1 row was expected.");
-    *row = out->back();
+    RETURN_IF_NOT_OK(BatchRows(&table, row, table->size()));
     batch_cnt_++;
     batch_num_++;
   }

mindspore/ccsrc/minddata/dataset/engine/datasetops/batch_op.h

@@ -203,8 +203,7 @@ class BatchOp : public ParallelOp {
   // @param int32_t size - batch_size
   // @param const std::unordered_map<std::string, int32_t>& column_name_id_map - column names to index mapping
   // @return Status The status code returned
-  static Status BatchRows(const std::unique_ptr<TensorQTable> *src, const std::unique_ptr<TensorQTable> *dest,
-                          dsize_t batch_size);
+  static Status BatchRows(const std::unique_ptr<TensorQTable> *src, TensorRow *dest, dsize_t batch_size);
 
   // @param table
   // @param const PadInfo &pad_info pad info
@@ -226,8 +225,7 @@ class BatchOp : public ParallelOp {
 
   // Generate buffer with batched tensors
   // @return Status The status code returned
-  Status MakeBatchedBuffer(std::pair<std::unique_ptr<TensorQTable>, CBatchInfo> table_pair,
-                           std::unique_ptr<DataBuffer> *db);
+  Status MakeBatchedBuffer(std::pair<std::unique_ptr<TensorQTable>, CBatchInfo> table_pair, TensorRow *new_row);
 
 #ifdef ENABLE_PYTHON
   // Function that calls pyfunc to perform map on batch
@@ -259,7 +257,7 @@ class BatchOp : public ParallelOp {
   // @return Status The status code returned
   Status LaunchThreadsAndInitOp();
 
-  Status GetNextRow(TensorRow *row) override;
+  Status GetNextRowPullMode(TensorRow *row) override;
 
 #ifdef ENABLE_PYTHON
   // Invoke batch size function with current BatchInfo to generate batch size.

mindspore/ccsrc/minddata/dataset/engine/datasetops/bucket_batch_by_length_op.cc

@@ -136,11 +136,11 @@ Status BucketBatchByLengthOp::operator()() {
     }
 
     // need to send EOE manually since we set state to idle in EoeRecieved()
-    std::unique_ptr<DataBuffer> eoe_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE);
-    RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(eoe_buffer)));
+    RETURN_IF_NOT_OK(out_connector_->SendEOE());
 
     RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&current_row));
   }
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
 
   return Status::OK();
 }
@@ -198,13 +198,11 @@ Status BucketBatchByLengthOp::PadAndBatchBucket(int32_t bucket_index, int32_t ba
   // PadColumns will change the data in bucket
   RETURN_IF_NOT_OK(BatchOp::PadColumns(bucket, pad_info_copy, column_name_id_map_));
 
-  std::unique_ptr<TensorQTable> batched_bucket = std::make_unique<TensorQTable>();
+  TensorRow batched_bucket;
   RETURN_IF_NOT_OK(BatchOp::BatchRows(bucket, &batched_bucket, batch_size));
   (*bucket)->clear();
 
-  std::unique_ptr<DataBuffer> batched_buffer = std::make_unique<DataBuffer>(batch_count_, DataBuffer::kDeBFlagNone);
-  batched_buffer->set_tensor_table(std::move(batched_bucket));
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(batched_buffer)));
+  RETURN_IF_NOT_OK(out_connector_->Add(std::move(batched_bucket), 0));
 
   batch_count_++;
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/build_sentence_piece_vocab_op.cc

@@ -57,6 +57,7 @@ Status BuildSentencePieceVocabOp::operator()() {
       RETURN_IF_NOT_OK(sentence_queue_->EmplaceBack(new_row));
       RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
     }
+    RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
     CHECK_FAIL_RETURN_UNEXPECTED(!eoe_warning, "no op should be after from_dataset (repeat detected)");
     eoe_warning = true;
   }
@@ -91,8 +92,8 @@ Status BuildSentencePieceVocabOp::SentenceThread() {
     }
     vocab_->set_model_proto(model_proto);
   }
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE)));
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF)));
+  RETURN_IF_NOT_OK(out_connector_->SendEOE());
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/build_vocab_op.cc

@@ -112,6 +112,7 @@ Status BuildVocabOp::operator()() {
       RETURN_IF_NOT_OK(distributor_queue_->EmplaceBack(new_row));
       RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
     }
+    RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
     CHECK_FAIL_RETURN_UNEXPECTED(!eoe_warning, "no op should be after from_dataset (repeat detected)");
     eoe_warning = true;
   }
@@ -184,8 +185,8 @@ Status BuildVocabOp::CollectorThread() {
     for (const std::string &sp_tk : special_tokens_) vocab_->append_word(sp_tk);
   }
 
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE)));
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF)));
+  RETURN_IF_NOT_OK(out_connector_->SendEOE());
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
   // then use std::nth_element to partial sort
   return Status::OK();
 }

mindspore/ccsrc/minddata/dataset/engine/datasetops/cache_base_op.cc

@@ -174,7 +174,6 @@ Status CacheBase::FetchSamplesToWorkers() {
 }
 
 Status CacheBase::FetchFromCache(int32_t worker_id) {
-  int64_t buffer_id = worker_id;
   std::unique_ptr<IOBlock> blk;
   do {
     RETURN_IF_NOT_OK(io_block_queues_[worker_id]->PopFront(&blk));
@@ -185,9 +184,9 @@ Status CacheBase::FetchFromCache(int32_t worker_id) {
         wait_for_workers_post_.Set();
       }
     } else if (blk->eof()) {
-      RETURN_IF_NOT_OK(out_connector_->Add(worker_id, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF)));
+      RETURN_IF_NOT_OK(out_connector_->SendEOF(worker_id));
     } else if (blk->eoe()) {
-      RETURN_IF_NOT_OK(out_connector_->Add(worker_id, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE)));
+      RETURN_IF_NOT_OK(out_connector_->SendEOE(worker_id));
     } else {
       std::vector<int64_t> keys;
       RETURN_IF_NOT_OK(blk->GetKeys(&keys));
@@ -195,8 +194,6 @@ Status CacheBase::FetchFromCache(int32_t worker_id) {
         // empty key is a quit signal for workers
         break;
       }
-      std::unique_ptr<DataBuffer> db = std::make_unique<DataBuffer>(buffer_id, DataBuffer::kDeBFlagNone);
-      std::unique_ptr<TensorQTable> que = std::make_unique<TensorQTable>();
       for (auto row_id : keys) {
         TensorRow row;
         // Block until the row shows up in the pool.
@@ -209,11 +206,8 @@ Status CacheBase::FetchFromCache(int32_t worker_id) {
             RETURN_STATUS_UNEXPECTED(errMsg);
           }
         }
-        que->push_back(std::move(row));
+        RETURN_IF_NOT_OK(out_connector_->Add(std::move(row), worker_id));
       }
-      db->set_tensor_table(std::move(que));
-      RETURN_IF_NOT_OK(out_connector_->Add(worker_id, std::move(db)));
-      buffer_id += num_workers_;
     }
   } while (true);
   return Status::OK();

mindspore/ccsrc/minddata/dataset/engine/datasetops/cache_merge_op.cc

@@ -76,30 +76,21 @@ Status CacheMergeOp::operator()() {
 // until it shows up in the pool.
 Status CacheMergeOp::WorkerEntry(int32_t worker_id) {
   TaskManager::FindMe()->Post();
-  std::shared_ptr<DatasetOp> cache_hit_stream = child_[kCacheHitChildIdx];
-  std::unique_ptr<DataBuffer> db_ptr;
-  RETURN_IF_NOT_OK(cache_hit_stream->GetNextBuffer(&db_ptr, worker_id));
-  while (!db_ptr->eof()) {
-    if (db_ptr->eoe()) {
+  TensorRow new_row;
+  auto child_iterator = std::make_unique<ChildIterator>(this, worker_id, kCacheHitChildIdx);
+  RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&new_row));
+  while (!new_row.eof()) {
+    if (new_row.eoe()) {
       RETURN_IF_NOT_OK(EoeReceived(worker_id));
-      db_ptr.reset();
-      RETURN_IF_NOT_OK(cache_hit_stream->GetNextBuffer(&db_ptr, worker_id));
+      RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&new_row));
     } else {
-      // See if there is any missing row
-      auto tbl = std::make_unique<TensorQTable>();
-      while (db_ptr->NumRows() > 0) {
-        TensorRow row;
-        RETURN_IF_NOT_OK(db_ptr->PopRow(&row));
-        if (row.empty()) {
-          auto row_id = row.getId();
-          // Block until the row shows up in the pool.
-          RETURN_IF_NOT_OK(cache_miss_.PopFront(row_id, &row));
-        }
-        tbl->push_back(std::move(row));
+      if (new_row.empty()) {
+        auto row_id = new_row.getId();
+        // Block until the row shows up in the pool.
+        RETURN_IF_NOT_OK(cache_miss_.PopFront(row_id, &new_row));
       }
-      db_ptr->set_tensor_table(std::move(tbl));
-      RETURN_IF_NOT_OK(out_connector_->Add(worker_id, std::move(db_ptr)));
-      RETURN_IF_NOT_OK(cache_hit_stream->GetNextBuffer(&db_ptr, worker_id));
+      RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row), worker_id));
+      RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&new_row));
     }
   }
   RETURN_IF_NOT_OK(EofReceived(worker_id));
@@ -111,16 +102,16 @@ Status CacheMergeOp::CacheMissWorkerEntry(int32_t workerId) {
   // We will simply pop TensorRow from the stream and insert them into the pool and
   // wake up any worker that is awaiting on the missing TensorRow.
   // If we see an eoe, ignore it. For eof, we exit.
-  std::shared_ptr<DatasetOp> cache_missing_stream = child_[kCacheMissChildIdx];
   // Before we start, cache the schema at the server. Pick one of the workers
   // do it. The schema should have been done at prepare time.
   if (workerId == 0) {
     RETURN_IF_NOT_OK(cache_client_->CacheSchema(column_name_id_map()));
   }
-  std::unique_ptr<DataBuffer> db_ptr;
-  RETURN_IF_NOT_OK(cache_missing_stream->GetNextBuffer(&db_ptr, workerId));
-  while (!db_ptr->eof()) {
-    if (db_ptr->eoe()) {
+  TensorRow new_row;
+  auto child_iterator = std::make_unique<ChildIterator>(this, workerId, kCacheMissChildIdx);
+  RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&new_row));
+  while (!new_row.eof()) {
+    if (new_row.eoe()) {
       // Ignore it.
       MS_LOG(DEBUG) << "Ignore eoe";
       // However we need to flush any left over from the async write buffer. But any error
@@ -135,36 +126,32 @@ Status CacheMergeOp::CacheMissWorkerEntry(int32_t workerId) {
         }
       }
     } else {
-      while (db_ptr->NumRows() > 0) {
-        TensorRow row;
-        RETURN_IF_NOT_OK(db_ptr->PopRow(&row));
-        row_id_type row_id = row.getId();
-        if (row_id < 0) {
-          std::string errMsg = "Expect positive row id: " + std::to_string(row_id);
-          RETURN_STATUS_UNEXPECTED(errMsg);
-        }
-        if (cache_missing_rows_) {
-          // Technically number of this row shows up in the cache miss stream is equal to the number
-          // of P() call. However the cleaner wants it too. So we need an extra copy.
-          TensorRowCacheRequest *rq;
-          RETURN_IF_NOT_OK(GetRq(row_id, &rq));
-          if (rq->GetState() == TensorRowCacheRequest::State::kEmpty) {
-            // We will send the request async. But any error we most
-            // likely ignore and continue.
-            Status rc;
-            rc = rq->AsyncSendCacheRequest(cache_client_, row);
-            if (rc.IsOk()) {
-              RETURN_IF_NOT_OK(io_que_->EmplaceBack(row_id));
-            } else if (rc == StatusCode::kMDOutOfMemory || rc == kMDNoSpace) {
-              cache_missing_rows_ = false;
-              cache_client_->ServerRunningOutOfResources();
-            }
+      row_id_type row_id = new_row.getId();
+      if (row_id < 0) {
+        std::string errMsg = "Expect positive row id: " + std::to_string(row_id);
+        RETURN_STATUS_UNEXPECTED(errMsg);
+      }
+      if (cache_missing_rows_) {
+        // Technically number of this row shows up in the cache miss stream is equal to the number
+        // of P() call. However the cleaner wants it too. So we need an extra copy.
+        TensorRowCacheRequest *rq;
+        RETURN_IF_NOT_OK(GetRq(row_id, &rq));
+        if (rq->GetState() == TensorRowCacheRequest::State::kEmpty) {
+          // We will send the request async. But any error we most
+          // likely ignore and continue.
+          Status rc;
+          rc = rq->AsyncSendCacheRequest(cache_client_, new_row);
+          if (rc.IsOk()) {
+            RETURN_IF_NOT_OK(io_que_->EmplaceBack(row_id));
+          } else if (rc == StatusCode::kMDOutOfMemory || rc == kMDNoSpace) {
+            cache_missing_rows_ = false;
+            cache_client_->ServerRunningOutOfResources();
           }
         }
-        RETURN_IF_NOT_OK(cache_miss_.Add(row_id, std::move(row)));
       }
+      RETURN_IF_NOT_OK(cache_miss_.Add(row_id, std::move(new_row)));
     }
-    RETURN_IF_NOT_OK(cache_missing_stream->GetNextBuffer(&db_ptr, workerId));
+    RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&new_row));
   }
   return Status::OK();
 }
@@ -265,14 +252,14 @@ Status CacheMergeOp::Builder::Build(std::shared_ptr<CacheMergeOp> *ptr) {
 Status CacheMergeOp::EoeReceived(int32_t worker_id) {
   // Send the eoe up.
   MS_LOG(DEBUG) << "Cache merge sending eoe";
-  return DatasetOp::EoeReceived(worker_id);
+  return out_connector_->SendEOE(worker_id);
 }
 
 // Base-class override for handling cases when an eof is received.
 Status CacheMergeOp::EofReceived(int32_t worker_id) {
   // Send the eof up.
   MS_LOG(DEBUG) << "Cache merge sending eof";
-  return DatasetOp::EofReceived(worker_id);
+  return out_connector_->SendEOF(worker_id);
 }
 
 Status CacheMergeOp::GetRq(row_id_type row_id, CacheMergeOp::TensorRowCacheRequest **out) {

mindspore/ccsrc/minddata/dataset/engine/datasetops/cache_op.cc

@@ -21,6 +21,7 @@
 #include "minddata/dataset/include/constants.h"
 #include "minddata/dataset/core/global_context.h"
 #include "minddata/dataset/engine/datasetops/repeat_op.h"
+#include "minddata/dataset/engine/dataset_iterator.h"
 #include "minddata/dataset/engine/data_buffer.h"
 #include "minddata/dataset/engine/execution_tree.h"
 #include "minddata/dataset/util/log_adapter.h"
@@ -104,15 +105,16 @@ Status CacheOp::CacheAllRows(int32_t worker_id) {
     }
     MS_LOG(INFO) << "CacheOp first epoch SAVE mode started. Worker: " << worker_id;
     // SAVE mode loop
-    std::unique_ptr<DataBuffer> db_ptr;
-    RETURN_IF_NOT_OK(this->GetNextInput(&db_ptr, worker_id, 0));
-    while (!db_ptr->eof()) {
-      if (!db_ptr->eoe()) {
+    TensorRow row;
+    auto child_iterator = std::make_unique<ChildIterator>(this, worker_id, 0);
+    RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&row));
+    while (!row.eof()) {
+      if (!row.eoe()) {
         Status rc;
         // Do the Async write if we attach to the shared memory.
-        rc = cache_client_->AsyncWriteBuffer(std::move(db_ptr));
+        rc = cache_client_->AsyncWriteRow(row);
         if (rc.StatusCode() == StatusCode::kMDNotImplementedYet) {
-          RETURN_IF_NOT_OK(cache_client_->WriteBuffer(std::move(db_ptr)));
+          RETURN_IF_NOT_OK(cache_client_->WriteRow(row));
         } else if (rc.IsError()) {
           return rc;
         }
@@ -122,12 +124,13 @@ Status CacheOp::CacheAllRows(int32_t worker_id) {
         // the eoe to indicate the end of the epoch, we should next expect to get the eof.
         // Drain this eof so that we don't leave it sitting there on a connector that we'll never fetch
         // from again.
-        RETURN_IF_NOT_OK(this->GetNextInput(&db_ptr, worker_id, 0));
-        if (!db_ptr->eof()) {
+        RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&row));
+        if (!row.eof()) {
           RETURN_STATUS_UNEXPECTED("Cache op expects to get an eof after eoe from child.");
         }
+        break;
       }
-      RETURN_IF_NOT_OK(this->GetNextInput(&db_ptr, worker_id, 0));
+      RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&row));
     }
   }
   // Let the main guy know we are done.

mindspore/ccsrc/minddata/dataset/engine/datasetops/concat_op.cc

@@ -78,9 +78,12 @@ void ConcatOp::Print(std::ostream &out, bool show_all) const {
 
 // Main entry point for Concat
 Status ConcatOp::operator()() {
-  children_num_ = static_cast<int32_t>(child_.size());
   TaskManager::FindMe()->Post();
-  std::unique_ptr<DataBuffer> buf;
+  children_num_ = static_cast<int32_t>(child_.size());
+  for (int32_t i = 0; i < children_num_; i++) {
+    children_iterators_.push_back(std::make_unique<ChildIterator>(this, 0, i));
+  }
+  TensorRow new_row;
   int eof_count = 0;
   int sample_number = 0;
   bool is_not_mappable = true;
@@ -95,26 +98,26 @@ Status ConcatOp::operator()() {
 
   while (eof_count == 0) {
     for (int i = 0; i < children_num_; i++) {
-      // 1. Read the first buffer
-      RETURN_IF_NOT_OK(child_[i]->GetNextBuffer(&buf));
-      if (buf->eof()) {
+      // 1. Read the first row
+      RETURN_IF_NOT_OK(children_iterators_[i]->FetchNextTensorRow(&new_row));
+      if (new_row.eof()) {
         eof_count++;
         continue;
       }
       // 2. Do verification as for column name, column data type and rank of column data
-      if (!buf->eoe()) {
-        RETURN_IF_NOT_OK(Verify(i, buf));
+      if (!new_row.eoe()) {
+        RETURN_IF_NOT_OK(Verify(i, new_row));
       }
       // 3. Put the data into output_connector
       if (!children_flag_and_nums_.empty()) {
         is_not_mappable = children_flag_and_nums_[i].first;
         is_not_mappable_or_second_ne_zero = is_not_mappable || (!children_flag_and_nums_[i].second);
       }
-      while (!buf->eoe() && !buf->eof()) {
+      while (!new_row.eoe() && !new_row.eof()) {
         // if dataset is not mappable or generator dataset which source is yield, cannot get the number of samples in
         // python layer), we use filtering to get data
         if (sample_number % num_shard == shard_index && is_not_mappable_or_second_ne_zero) {
-          RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(buf)));
+          RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row)));
         } else if (!is_not_mappable_or_second_ne_zero) {
           // if dataset is mappable or generator dataset which source is not yield,
           // get the start and end subscripts of valid values
@@ -122,7 +125,7 @@ Status ConcatOp::operator()() {
 
           // determine whether the data allocated to the current shard id is false data
           if (f(fv, sv, shard_index)) {
-            RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(buf)));
+            RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row)));
           }
         }
 
@@ -131,7 +134,7 @@ Status ConcatOp::operator()() {
           sample_number++;
         }
 
-        RETURN_IF_NOT_OK(child_[i]->GetNextBuffer(&buf));
+        RETURN_IF_NOT_OK(children_iterators_[i]->FetchNextTensorRow(&new_row));
       }
 
       // if dataset is mappable,We don't use filtering to pick data.
@@ -143,8 +146,7 @@ Status ConcatOp::operator()() {
 
     // 4. Add eoe buffer after get buffer from all child
     if (eof_count == 0) {
-      auto eoe_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE);
-      RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(eoe_buffer)));
+      RETURN_IF_NOT_OK(out_connector_->SendEOE());
     }
     UpdateRepeatAndEpochCounter();
   }
@@ -152,15 +154,11 @@ Status ConcatOp::operator()() {
                                "Something went wrong, eof count does not match the number of children.");
   // 5. Add eof buffer in the end manually
   MS_LOG(DEBUG) << "Add the eof buffer manually in the end.";
-  auto eof_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF);
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(eof_buffer)));
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
   return Status::OK();
 }
 
-Status ConcatOp::Verify(int32_t id, const std::unique_ptr<DataBuffer> &buf) {
-  TensorRow new_row;
-  RETURN_IF_NOT_OK(buf->GetRow(0, &new_row));
-
+Status ConcatOp::Verify(int32_t id, const TensorRow &new_row) {
   if (id == 0) {
     // Obtain the data type and data rank in child[0]
     for (auto item : new_row) {

mindspore/ccsrc/minddata/dataset/engine/datasetops/concat_op.h

@@ -21,6 +21,7 @@
 #include <unordered_map>
 #include <vector>
 #include <utility>
+#include "minddata/dataset/engine/dataset_iterator.h"
 #include "minddata/dataset/engine/datasetops/pipeline_op.h"
 #include "minddata/dataset/engine/datasetops/source/sampler/distributed_sampler.h"
 
@@ -111,7 +112,7 @@ class ConcatOp : public PipelineOp {
   Status GetNumClasses(int64_t *num_classes) override;
 
  private:
-  Status Verify(int32_t id, const std::unique_ptr<DataBuffer> &buf);
+  Status Verify(int32_t id, const TensorRow &tensor_row);
 
   int32_t children_num_;                                     // The num of child of parent node.
   std::unordered_map<std::string, int32_t> column_name_id_;  // Mapping between col index and col name
@@ -120,6 +121,8 @@ class ConcatOp : public PipelineOp {
   std::shared_ptr<SamplerRT> sampler_;
   std::vector<std::pair<int, int>> children_flag_and_nums_;
   std::vector<std::pair<int, int>> children_start_end_index_;
+
+  std::vector<std::unique_ptr<ChildIterator>> children_iterators_;  // Iterator for fetching.
 };
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/engine/datasetops/dataset_op.cc

@@ -252,45 +252,15 @@ void DatasetOp::Print(std::ostream &out, bool show_all) const {
   }
 }
 
-Status DatasetOp::GetNextRow(TensorRow *row) {
+Status DatasetOp::GetNextRowPullMode(TensorRow *row) {
   RETURN_UNEXPECTED_IF_NULL(child_[0]);
-  return child_[0]->GetNextRow(row);
+  return child_[0]->GetNextRowPullMode(row);
 }
 
 // Gets the next buffer from the given child
-Status DatasetOp::GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id, bool retry_if_eoe) {
+Status DatasetOp::GetNextRow(TensorRow *row, int32_t worker_id, bool retry_if_eoe) {
   // pop is a blocked call and will throw an interruption if the whole group shuts down.
-  RETURN_IF_NOT_OK(out_connector_->PopWithRetry(static_cast<int>(worker_id), p_buffer, retry_if_eoe));
-  return Status::OK();
-}
-
-// Gets the next buffer from the given child .  This function also has built-in eoe and eof
-// message handling so that child classes don't have to manually code pass-through logic when
-// those messages are received.
-Status DatasetOp::GetNextInput(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id, int32_t child_index) {
-  if (child_.size() == 0) {
-    return this->GetNextBuffer(p_buffer, worker_id);
-  }
-  CHECK_FAIL_RETURN_UNEXPECTED(child_index < child_.size(),
-                               "Invalid data, child index too big : " + std::to_string(child_index));
-  std::shared_ptr<DatasetOp> child = child_[child_index];
-  std::unique_ptr<DataBuffer> buf;
-  RETURN_IF_NOT_OK(child->GetNextBuffer(&buf, worker_id));
-  // Loop until non EOE is received
-  while (buf->eoe()) {
-    UpdateRepeatAndEpochCounter();
-    RETURN_IF_NOT_OK(EoeReceived(worker_id));
-    if (state_ == OpState::kDeOpIdle) {
-      *p_buffer = std::move(buf);
-      return Status::OK();
-    }
-    RETURN_IF_NOT_OK(child->GetNextBuffer(&buf, worker_id));
-  }
-  // Check if the last buf is next eof
-  if (buf->eof()) {
-    RETURN_IF_NOT_OK(EofReceived(worker_id));
-  }
-  *p_buffer = std::move(buf);
+  RETURN_IF_NOT_OK(out_connector_->PopWithRetry(static_cast<int>(worker_id), row, retry_if_eoe));
   return Status::OK();
 }
 
@@ -328,18 +298,12 @@ Status DatasetOp::GetClassIndexing(std::vector<std::pair<std::string, std::vecto
 // Performs handling for when an eoe message is received.
 // The base class implementation simply flows the eoe message to output. Derived classes
 // may override if they need to perform special eoe handling.
-Status DatasetOp::EoeReceived(int32_t worker_id) {
-  std::unique_ptr<DataBuffer> eoe_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE);
-  return (out_connector_->Add(static_cast<int>(worker_id), std::move(eoe_buffer)));
-}
+Status DatasetOp::EoeReceived(int32_t worker_id) { return out_connector_->SendEOE(worker_id); }
 
 // Performs handling for when an eof message is received.
 // The base class implementation simply flows the eof message to output. Derived classes
 // may override if they need to perform special eof handling.
-Status DatasetOp::EofReceived(int32_t worker_id) {
-  std::unique_ptr<DataBuffer> eof_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF);
-  return (out_connector_->Add(static_cast<int>(worker_id), std::move(eof_buffer)));
-}
+Status DatasetOp::EofReceived(int32_t worker_id) { return out_connector_->SendEOF(worker_id); }
 
 // During tree prepare phase, operators may have specific post-operations to perform depending on their role.
 Status DatasetOp::PrepareOperator() {

mindspore/ccsrc/minddata/dataset/engine/datasetops/dataset_op.h

@@ -129,7 +129,7 @@ class DatasetOp : public std::enable_shared_from_this<DatasetOp> {
   /// \param show_all - A bool to control if you want to show all info or just a summary
   virtual void Print(std::ostream &out, bool show_all) const;
 
-  virtual Status GetNextRow(TensorRow *row);
+  virtual Status GetNextRowPullMode(TensorRow *row);
 
   /// \brief << Stream output operator overload
   /// \notes This allows you to write the debug print info using stream operators
@@ -149,35 +149,17 @@ class DatasetOp : public std::enable_shared_from_this<DatasetOp> {
   virtual Status operator()() = 0;
 
   /// \brief Gets the next buffer from the given child
-  /// \notes See GetNextInput for similar function that has built-in message handling
-  /// \param p_buffer - The shared pointer for the fetched buffer to return (by reference)
-  /// \param worker_id - The worker id
-  /// \return Status The status code returned
-  virtual Status GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id) {
-    return GetNextBuffer(p_buffer, worker_id, false);
-  }
-
-  /// \brief Gets the next buffer from the given child
-  /// \notes See GetNextInput for similar function that has built-in message handling
-  /// \param p_buffer - The shared pointer for the fetched buffer to return (by reference)
+  /// \param row[out] - Fetched TensorRow
+  /// \param worker_id[in] - The worker id, default to 0.
   /// \return Status The status code returned
-  virtual Status GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer) { return GetNextBuffer(p_buffer, 0, false); }
+  virtual Status GetNextRow(TensorRow *row, int32_t worker_id = 0) { return GetNextRow(row, worker_id, false); }
 
   /// \brief Gets the next buffer from the given child
-  /// \notes See GetNextInput for similar function that has built-in message handling
-  /// \param p_buffer - The shared pointer for the fetched buffer to return (by reference)
-  /// \param worker_id - The worker id
+  /// \param row[out] - Fetched TensorRow
+  /// \param worker_id[in] - The worker id, default to 0.
   /// \param retry_if_eoe Set this flag to true to allow calling pop() again after the first pop() returns EOE.
   /// \return Status The status code returned
-  virtual Status GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id, bool retry_if_eoe);
-
-  /// \brief Gets the next buffer from the given child .  This function also has built-in eoe and eof
-  ///     message handling so that child classes don't have to manually code pass-through logic when
-  ///     those messages are received.
-  /// \param p_buffer - The shared pointer for the fetched buffer to return (by reference)
-  /// \param worker_id - The worker id
-  /// \return Status The status code returned
-  Status GetNextInput(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id = 0, int32_t child_index = 0);
+  virtual Status GetNextRow(TensorRow *row, int32_t worker_id, bool retry_if_eoe);
 
   /// \brief Gets the batch size
   /// \return Status - The status code return

mindspore/ccsrc/minddata/dataset/engine/datasetops/device_queue_op.cc

@@ -93,21 +93,18 @@ Status DeviceQueueOp::EoeReceived(int32_t worker_id) {
   return Status::OK();
 }
 
-Status DeviceQueueOp::CheckExceptions(const std::unique_ptr<DataBuffer> &buffer) const {
-  // this method checks if the buffer meets the conditions to be sent to TDT
-  if (buffer->NumRows() != 0) {
-    TensorRow row;
-    buffer->GetRow(0, &row);
-    for (const auto &item : row) {
-      CHECK_FAIL_RETURN_UNEXPECTED(item->type().IsNumeric(), "Invalid data, cannot send string tensor to device.");
-      CHECK_FAIL_RETURN_UNEXPECTED(item->HasData(), "Invalid data, cannot send tensor with no data to device.");
-    }
+Status DeviceQueueOp::CheckExceptions(const TensorRow &row) const {
+  // this method checks if the row meets the conditions to be sent to TDT
+  for (const auto &item : row) {
+    CHECK_FAIL_RETURN_UNEXPECTED(item->type().IsNumeric(), "Invalid data, cannot send string tensor to device.");
+    CHECK_FAIL_RETURN_UNEXPECTED(item->HasData(), "Invalid data, cannot send tensor with no data to device.");
   }
   return Status::OK();
 }
 
 Status DeviceQueueOp::operator()() {
   TaskManager::FindMe()->Post();
+  child_iterator_ = std::make_unique<ChildIterator>(this, 0, 0);
 
 #ifdef ENABLE_DUMP_IR
   if (md_channel_info_ == nullptr) {
@@ -163,43 +160,39 @@ Status DeviceQueueOp::SendDataToAscend() {
   md_channel_info_->RecordBatchQueue(ChildOpConnectorSize());
   md_channel_info_->RecordPreprocessBatch(0);
 #endif
-  std::unique_ptr<DataBuffer> current_buffer;
-  RETURN_IF_NOT_OK(GetNextInput(&current_buffer));
-
-  while (!current_buffer->eof() && !is_break_loop) {
-    while (!current_buffer->eoe() && !is_break_loop) {
-      RETURN_IF_NOT_OK(CheckExceptions(current_buffer));
-      TensorRow currRow;
-      for (int row_id = 0; row_id < current_buffer->NumRows(); row_id++) {
-        RETURN_IF_NOT_OK(current_buffer->GetRow(row_id, &currRow));
-        WaitContinueSignal();
+  TensorRow curr_row;
+  RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&curr_row));
+  while (!curr_row.eof() && !is_break_loop) {
+    while (!curr_row.eoe() && !is_break_loop) {
+      RETURN_IF_NOT_OK(CheckExceptions(curr_row));
+      WaitContinueSignal();
 #ifdef ENABLE_DUMP_IR
-        md_channel_info_->RecordBatchQueue(ChildOpConnectorSize());
-        md_channel_info_->RecordPreprocessBatch(send_batch);
-        md_channel_info_->RecordPushStartTime();
+      md_channel_info_->RecordBatchQueue(ChildOpConnectorSize());
+      md_channel_info_->RecordPreprocessBatch(send_batch);
+      md_channel_info_->RecordPushStartTime();
 #endif
-        RETURN_IF_NOT_OK(SendRowToTdt(currRow, isProfilingEnable, &tdt_cost));
-        ProfilingRecorder(isProfilingEnable, profiling_node, send_batch, tdt_cost, &batch_start_time, &end_time,
-                          connector_capacity, connector_size);
-        send_batch++;
+      RETURN_IF_NOT_OK(SendRowToTdt(curr_row, isProfilingEnable, &tdt_cost));
+      ProfilingRecorder(isProfilingEnable, profiling_node, send_batch, tdt_cost, &batch_start_time, &end_time,
+                        connector_capacity, connector_size);
+      send_batch++;
 #ifdef ENABLE_DUMP_IR
-        md_channel_info_->RecordBatchQueue(ChildOpConnectorSize());
-        md_channel_info_->RecordPreprocessBatch(send_batch);
-        md_channel_info_->RecordPushEndTime();
+      md_channel_info_->RecordBatchQueue(ChildOpConnectorSize());
+      md_channel_info_->RecordPreprocessBatch(send_batch);
+      md_channel_info_->RecordPushEndTime();
 #endif
 
-        if (total_batch_ > 0 && send_batch >= total_batch_) {
-          is_break_loop = true;
-          break;
-        }
+      if (total_batch_ > 0 && send_batch >= total_batch_) {
+        is_break_loop = true;
+        break;
       }
+
       if (isProfilingEnable) {
         connector_size = ChildOpConnectorSize();
         connector_capacity = ChildOpConnectorCapacity();
       }
-      RETURN_IF_NOT_OK(GetNextInput(&current_buffer));
+      RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&curr_row));
     }
-    if (current_buffer->eoe() && send_epoch_end_) {
+    if (curr_row.eoe() && send_epoch_end_) {
       TensorRow currRow;
       auto status = tdtInstancePtr->hostPush(currRow, true, channel_name_, isProfilingEnable, tdt_cost,
                                              ACL_TENSOR_DATA_END_OF_SEQUENCE);
@@ -219,7 +212,7 @@ Status DeviceQueueOp::SendDataToAscend() {
       connector_capacity = ChildOpConnectorCapacity();
       tree_->SetEpochEnd();
     }
-    RETURN_IF_NOT_OK(GetNextInput(&current_buffer));
+    RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&curr_row));
   }
 
   // now we use this flag to judge whether exception raised.
@@ -444,27 +437,23 @@ Status DeviceQueueOp::WorkerEntry(int32_t worker_id) {
   // Every thread use cuda api should SetThreadDevice
   RETURN_IF_NOT_OK(SetThreadDevice());
   TaskManager::FindMe()->Post();
-  std::unique_ptr<DataBuffer> current_buffer;
+  TensorRow current_row;
   uint32_t batch_num = 0;
-  RETURN_IF_NOT_OK(receive_queues_[worker_id]->PopFront(&current_buffer));
-  while (!current_buffer->quit() && !GpuBufferMgr::GetInstance().IsClosed()) {
-    TensorRow curr_row;
-    for (int row_id = 0; row_id < current_buffer->NumRows() && !GpuBufferMgr::GetInstance().IsClosed(); row_id++) {
-      RETURN_IF_NOT_OK(current_buffer->GetRow(row_id, &curr_row));
-      std::vector<device::DataItemGpu> items;
-      for (int i = 0; i < curr_row.size(); i++) {
-        device::DataItemGpu data_item;
-        data_item.data_len_ = static_cast<size_t>(curr_row[i]->SizeInBytes());
-        data_item.data_ptr_ = nullptr;
-        data_item.worker_id_ = worker_id;
-        items.push_back(data_item);
-      }
-      RETURN_IF_NOT_OK(MallocForGPUData(&items, curr_row, worker_id));
-      RETURN_IF_NOT_OK(gpu_item_connector_->Add(worker_id, std::move(items)));
-      batch_num++;
+  RETURN_IF_NOT_OK(receive_queues_[worker_id]->PopFront(&current_row));
+  while (!current_row.quit() && !GpuBufferMgr::GetInstance().IsClosed()) {
+    std::vector<device::DataItemGpu> items;
+    for (int i = 0; i < current_row.size(); i++) {
+      device::DataItemGpu data_item;
+      data_item.data_len_ = static_cast<size_t>(current_row[i]->SizeInBytes());
+      data_item.data_ptr_ = nullptr;
+      data_item.worker_id_ = worker_id;
+      items.push_back(data_item);
     }
+    RETURN_IF_NOT_OK(MallocForGPUData(&items, current_row, worker_id));
+    RETURN_IF_NOT_OK(gpu_item_connector_->Add(worker_id, std::move(items)));
+    batch_num++;
 
-    RETURN_IF_NOT_OK(receive_queues_[worker_id]->PopFront(&current_buffer));
+    RETURN_IF_NOT_OK(receive_queues_[worker_id]->PopFront(&current_row));
   }
 
   MS_LOG(INFO) << "Device queue worker id " << worker_id << "proc " << batch_num << "batch.";
@@ -477,31 +466,31 @@ Status DeviceQueueOp::WorkerEntry(int32_t worker_id) {
 Status DeviceQueueOp::SendDataToGPU() {
   RETURN_IF_NOT_OK(LaunchParallelCopyThread());
   MS_LOG(INFO) << "Device queue, sending data to GPU.";
-  std::unique_ptr<DataBuffer> current_buffer;
-  RETURN_IF_NOT_OK(GetNextInput(&current_buffer));
+  TensorRow current_row;
+  RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&current_row));
   int64_t num_buf = 0;
   bool is_break_loop = false;
-  while (!current_buffer->eof() && !is_break_loop && !GpuBufferMgr::GetInstance().IsClosed()) {
-    while (!current_buffer->eoe() && !is_break_loop && !GpuBufferMgr::GetInstance().IsClosed()) {
-      RETURN_IF_NOT_OK(CheckExceptions(current_buffer));
-      RETURN_IF_NOT_OK(receive_queues_[num_buf++ % num_workers_]->Add(std::move(current_buffer)));
+  while (!current_row.eof() && !is_break_loop && !GpuBufferMgr::GetInstance().IsClosed()) {
+    while (!current_row.eoe() && !is_break_loop && !GpuBufferMgr::GetInstance().IsClosed()) {
+      RETURN_IF_NOT_OK(CheckExceptions(current_row));
+      RETURN_IF_NOT_OK(receive_queues_[num_buf++ % num_workers_]->Add(std::move(current_row)));
       if (!TaskManager::FindMe()->Interrupted() && !GpuBufferMgr::GetInstance().IsClosed()) {
-        RETURN_IF_NOT_OK(GetNextInput(&current_buffer));
+        RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&current_row));
       } else {
         is_break_loop = true;
       }
     }
 
     if (!TaskManager::FindMe()->Interrupted() && !GpuBufferMgr::GetInstance().IsClosed()) {
-      RETURN_IF_NOT_OK(GetNextInput(&current_buffer));
+      RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&current_row));
     } else {
       is_break_loop = true;
     }
   }
 
   for (uint32_t index = 0; index < num_workers_; index++) {
-    auto quit = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagQuit);
-    RETURN_IF_NOT_OK(receive_queues_[num_buf++ % num_workers_]->Add(std::move(quit)));
+    TensorRow quit_flag(TensorRow::kFlagQuit);
+    RETURN_IF_NOT_OK(receive_queues_[num_buf++ % num_workers_]->Add(std::move(quit_flag)));
   }
 
   MS_LOG(INFO) << "Device queue receive " << num_buf - num_workers_ << " batch.";
@@ -537,10 +526,9 @@ Status DeviceQueueOp::SendDataToCPU() {
   MS_LOG(INFO) << "Device queue, sending data to CPU.";
   int64_t total_batch = 0;
 
-  std::unique_ptr<ChildIterator> child_iterator = std::make_unique<ChildIterator>(this, 0, 0);
-  while (!(child_iterator->eof_handled())) {
+  while (!(child_iterator_->eof_handled())) {
     TensorRow curr_row;
-    RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&curr_row));
+    RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&curr_row));
 
     if (!curr_row.empty()) {
       for (auto &tensor : curr_row) {

mindspore/ccsrc/minddata/dataset/engine/datasetops/device_queue_op.h

@@ -23,6 +23,8 @@
 
 #include "minddata/dataset/engine/datasetops/pipeline_op.h"
 #include "minddata/dataset/engine/datasetops/repeat_op.h"
+#include "minddata/dataset/engine/dataset_iterator.h"
+
 #include "minddata/dataset/engine/perf/device_queue_tracing.h"
 #include "minddata/dataset/util/status.h"
 #ifdef ENABLE_DUMP_IR
@@ -182,9 +184,9 @@ class DeviceQueueOp : public PipelineOp {
   std::string Name() const override { return kDeviceQueueOp; }
 
  private:
-  //  Name: checkExceptions(DataBuffer);
-  //  Description: Check whether the dataBuffer meets the condition for performing DeviceQueueOp
-  Status CheckExceptions(const std::unique_ptr<DataBuffer> &buffer) const;
+  //  Name: checkExceptions(TensorRow);
+  //  Description: Check whether the TensorRow meets the condition for performing DeviceQueueOp
+  Status CheckExceptions(const TensorRow &row) const;
 
  private:
 #ifdef ENABLE_TDTQUE
@@ -204,7 +206,7 @@ class DeviceQueueOp : public PipelineOp {
   Status WorkerEntry(int32_t worker_id);
   Status SetThreadDevice();
 
-  QueueList<std::unique_ptr<DataBuffer>> receive_queues_;
+  QueueList<TensorRow> receive_queues_;
   std::vector<std::shared_ptr<MemoryPool>> pool_;
   std::unique_ptr<GpuItemConnector> gpu_item_connector_;
   uint32_t num_workers_;
@@ -216,6 +218,8 @@ class DeviceQueueOp : public PipelineOp {
 #endif
 
   Status SendDataToCPU();
+
+  std::unique_ptr<ChildIterator> child_iterator_;
   std::string channel_name_;
   DeviceType device_type_;
   const int32_t device_id_;

mindspore/ccsrc/minddata/dataset/engine/datasetops/epoch_ctrl_op.cc

@@ -61,24 +61,21 @@ void EpochCtrlOp::Print(std::ostream &out, bool show_all) const {
   }
 }
 
-Status EpochCtrlOp::GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id, bool retry_if_eoe) {
+Status EpochCtrlOp::GetNextRow(TensorRow *row, int32_t worker_id, bool retry_if_eoe) {
   if (child_.empty()) {
     RETURN_STATUS_UNEXPECTED("EpochCtrlOp can't be the leaf node.");
   }
 
-  std::unique_ptr<DataBuffer> buf;
-
   // `retry_if_eoe` is false because EpochCtrlOp does not eat EOE.
-  RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buf, worker_id, false));
+  RETURN_IF_NOT_OK(child_[0]->GetNextRow(row, worker_id, false));
 
   // Only intercept EOE for EoeReceived processing, after that the EOE is forwarded to next op.
   // Other databuffers containing data or EOF will simply be forwarded.
   // EOF can simply be forwarded because this op does not spawn any thread, thus does not require clean up.
-  if (buf->eoe()) {
+  if (row->eoe()) {
     RETURN_IF_NOT_OK(EoeReceived(worker_id));
   }
 
-  *p_buffer = std::move(buf);
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/epoch_ctrl_op.h

@@ -59,7 +59,7 @@ class EpochCtrlOp : public RepeatOp {
   // Since EpochCtrlOp is derived from RepeatOp which is an inlined op, getting a buffer from us
   // will simply bounce you to get a buffer from our child.
   // Epoch Control Op does not eat the EOE, it will pass the EOE to the next op.
-  Status GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id, bool retry_if_eoe) override;
+  Status GetNextRow(TensorRow *row, int32_t worker_id, bool retry_if_eoe) override;
 
   // Base-class override for handling cases when an eoe is received.
   // @param worker_id - The worker id

mindspore/ccsrc/minddata/dataset/engine/datasetops/filter_op.cc

@@ -23,7 +23,6 @@
 #include "minddata/dataset/core/global_context.h"
 #include "minddata/dataset/core/tensor.h"
 #include "minddata/dataset/engine/data_buffer.h"
-#include "minddata/dataset/engine/execution_tree.h"
 #include "minddata/dataset/kernels/tensor_op.h"
 #include "minddata/dataset/util/log_adapter.h"
 #include "minddata/dataset/util/task_manager.h"
@@ -80,8 +79,8 @@ Status FilterOp::EofReceived(int32_t) { return Status::OK(); }
 Status FilterOp::EoeReceived(int32_t) { return Status::OK(); }
 
 // Validating if each of the input_columns exists in the DataBuffer.
-Status FilterOp::ValidateInColumns(const std::vector<std::string> *input_columns) {
-  for (const auto &inCol : *input_columns) {
+Status FilterOp::ValidateInColumns(const std::vector<std::string> &input_columns) {
+  for (const auto &inCol : input_columns) {
     bool found = column_name_id_map_.find(inCol) != column_name_id_map_.end() ? true : false;
     if (!found) {
       std::string err_msg = "Invalid parameter, column name: " + inCol + " does not exist in the dataset columns.";
@@ -111,68 +110,51 @@ void FilterOp::Print(std::ostream &out, bool show_all) const {
 }
 
 Status FilterOp::WorkerEntry(int32_t worker_id) {
+  std::unique_ptr<ChildIterator> child_iterator = std::make_unique<ChildIterator>(this, worker_id, 0);
+
   // Handshake with TaskManager that thread creation is successful.
   TaskManager::FindMe()->Post();
-  std::unique_ptr<DataBuffer> in_buffer;
   bool worker_stop = false;
   while (worker_stop == false) {
-    // Getting a databuffer to work on.
-    RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&in_buffer, worker_id));
-    if (in_buffer->eoe()) {
-      filter_queues_[worker_id]->EmplaceBack(std::make_pair(std::move(in_buffer), filterCtrl::kFilterEoe));
+    // Getting a TensorRow to work on.
+    TensorRow in_row;
+    RETURN_IF_NOT_OK(child_iterator->FetchNextTensorRow(&in_row));
+
+    if (in_row.eoe()) {
+      RETURN_IF_NOT_OK(filter_queues_[worker_id]->EmplaceBack(std::make_pair(in_row, filterCtrl::kFilterEoe)));
       continue;
-    } else if (in_buffer->eof()) {
-      filter_queues_[worker_id]->EmplaceBack(std::make_pair(std::move(in_buffer), filterCtrl::kFilterEof));
+    } else if (in_row.eof()) {
+      RETURN_IF_NOT_OK(filter_queues_[worker_id]->EmplaceBack(std::make_pair(in_row, filterCtrl::kFilterEof)));
       worker_stop = true;
       continue;
     }
 
-    RETURN_IF_NOT_OK(CheckColumns(in_buffer.get(), &in_columns_));
+    RETURN_IF_NOT_OK(ValidateInColumns(in_columns_));
 
-    // if the databuffer was all filtered, it is marked as kFilterEmpty.
-    // if the databuffer was partially filtered, it is marked as kFilterPartial.
-    // if the databuffer was not filtered, it is marked as kFilterFull.
-    int32_t num_rows = in_buffer->NumRows();
-    std::unique_ptr<TensorQTable> new_tensor_table;
-    RETURN_IF_NOT_OK(WorkerCompute(in_buffer.get(), &new_tensor_table));
+    bool result;
+    RETURN_IF_NOT_OK(WorkerCompute(in_row, &result));
 
-    if (new_tensor_table->empty()) {
-      RETURN_IF_NOT_OK(
-        filter_queues_[worker_id]->EmplaceBack(std::make_pair(std::move(in_buffer), filterCtrl::kFilterEmpty)));
-    } else if (new_tensor_table->size() == num_rows) {
-      in_buffer->set_tensor_table(std::move(new_tensor_table));
+    if (result)
       RETURN_IF_NOT_OK(
-        filter_queues_[worker_id]->EmplaceBack(std::make_pair(std::move(in_buffer), filterCtrl::kFilterFull)));
-    } else {  // kFilterPartial
-      in_buffer->set_tensor_table(std::move(new_tensor_table));
+        filter_queues_[worker_id]->EmplaceBack(std::make_pair(std::move(in_row), filterCtrl::kFilterFull)));
+    else
       RETURN_IF_NOT_OK(
-        filter_queues_[worker_id]->EmplaceBack(std::make_pair(std::move(in_buffer), filterCtrl::kFilterPartial)));
-    }
+        filter_queues_[worker_id]->EmplaceBack(std::make_pair(std::move(in_row), filterCtrl::kFilterEmpty)));
   }
   return Status::OK();
 }
 
-Status FilterOp::WorkerCompute(DataBuffer *in_buffer, std::unique_ptr<TensorQTable> *out) {
-  *out = std::make_unique<TensorQTable>();
-  int32_t num_rows = in_buffer->NumRows();
-  for (int32_t i = 0; i < num_rows; i++) {
-    TensorRow to_process;
-    TensorRow cur_row;
-    RETURN_IF_NOT_OK(in_buffer->PopRow(&cur_row));
-    if (in_columns_.empty() == true) {
-      MS_LOG(INFO) << "Input columns in filter operator is empty, will apply to the all column in the current table.";
-      to_process = cur_row;
-    } else {
-      (void)std::transform(
-        in_columns_.begin(), in_columns_.end(), std::back_inserter(to_process),
-        [&cur_row, this](const auto &it) -> std::shared_ptr<Tensor> { return cur_row[column_name_id_map_[it]]; });
-    }
-    bool predicate = true;
-    RETURN_IF_NOT_OK(InvokePredicateFunc(to_process, &predicate));
-    if (predicate) {
-      (*out)->push_back(std::move(cur_row));
-    }
+Status FilterOp::WorkerCompute(const TensorRow &in_row, bool *out_predicate) {
+  TensorRow to_process;
+  if (in_columns_.empty() == true) {
+    MS_LOG(INFO) << "Input columns in filter operator is empty, will apply to the all column in the current table.";
+    to_process = in_row;
+  } else {
+    (void)std::transform(
+      in_columns_.begin(), in_columns_.end(), std::back_inserter(to_process),
+      [&in_row, this](const auto &it) -> std::shared_ptr<Tensor> { return in_row[column_name_id_map_[it]]; });
   }
+  RETURN_IF_NOT_OK(InvokePredicateFunc(to_process, out_predicate));
   return Status::OK();
 }
 
@@ -190,20 +172,24 @@ Status FilterOp::Collector() {
   bool collector_stop = false;
   uint64_t task_id_cnt = 0;
   uint64_t out_id_cnt = 0;
-  std::pair<std::unique_ptr<DataBuffer>, filterCtrl> in_pair;
+  std::pair<TensorRow, filterCtrl> in_pair;
   while (collector_stop == false) {
     uint32_t w_id = task_id_cnt % num_workers_;
     RETURN_IF_NOT_OK(filter_queues_[w_id]->PopFront(&in_pair));
     if (in_pair.second == filterCtrl::kFilterFull || in_pair.second == filterCtrl::kFilterPartial ||
         in_pair.second == filterCtrl::kFilterEoe) {
-      if (in_pair.second == filterCtrl::kFilterEoe) UpdateRepeatAndEpochCounter();
       uint32_t out_task_id = out_id_cnt % num_workers_;
-      RETURN_IF_NOT_OK(out_connector_->Add(static_cast<int>(out_task_id), std::move(in_pair.first)));
+      if (in_pair.second == filterCtrl::kFilterEoe) {
+        UpdateRepeatAndEpochCounter();
+        RETURN_IF_NOT_OK(out_connector_->SendEOE(static_cast<int>(out_task_id)));
+      } else {
+        RETURN_IF_NOT_OK(out_connector_->Add(std::move(in_pair.first), static_cast<int>(out_task_id)));
+      }
       out_id_cnt++;
       task_id_cnt++;
     } else if (in_pair.second == filterCtrl::kFilterEof) {
       uint32_t out_task_id = out_id_cnt % num_workers_;
-      RETURN_IF_NOT_OK(out_connector_->Add(static_cast<int>(out_task_id), std::move(in_pair.first)));
+      RETURN_IF_NOT_OK(out_connector_->SendEOF(static_cast<int>(out_task_id)));
       collector_stop = true;
     } else {  // kFilterEmpty
       task_id_cnt++;
@@ -212,18 +198,6 @@ Status FilterOp::Collector() {
   return Status::OK();
 }
 
-// Private function for checking the column legality.
-Status FilterOp::CheckColumns(const DataBuffer *in_buf, const std::vector<std::string> *input_columns) {
-  int32_t num_rows = in_buf->NumRows();
-  int32_t num_cols = in_buf->NumCols();
-  if (num_rows == 0 || num_cols == 0) {
-    RETURN_STATUS_UNEXPECTED("FilterOp is getting an empty DataBuffer.");
-  }
-  // Check if there is invalid column name in the inColumns.
-  RETURN_IF_NOT_OK(ValidateInColumns(input_columns));
-  return Status::OK();
-}
-
 Status FilterOp::CheckInput(const TensorRow &input) const {
   for (auto &item : input) {
     if (item == nullptr) {

mindspore/ccsrc/minddata/dataset/engine/datasetops/filter_op.h

@@ -21,6 +21,7 @@
 #include <string>
 #include <utility>
 #include <vector>
+#include "minddata/dataset/engine/dataset_iterator.h"
 #include "minddata/dataset/engine/datasetops/parallel_op.h"
 #include "minddata/dataset/kernels/tensor_op.h"
 #include "minddata/dataset/util/queue.h"
@@ -133,7 +134,7 @@ class FilterOp : public ParallelOp {
   std::vector<std::string> in_columns_;
 
   // Internal queue for filter.
-  QueueList<std::pair<std::unique_ptr<DataBuffer>, filterCtrl>> filter_queues_;
+  QueueList<std::pair<TensorRow, filterCtrl>> filter_queues_;
 
   // Private function for worker/thread to loop continuously. It comprises the main
   // logic of FilterOp, getting the data from previous Op, validating user specified column names,
@@ -143,11 +144,10 @@ class FilterOp : public ParallelOp {
   Status WorkerEntry(int32_t worker_id) override;  //  In: workerId assigned by tree_
 
   // Filter the data by  predicate function .
-  // @param in_buffer input data buffer.
-  // @param to_proess_indices Indices of columns to be processed.
-  // @param out data buffer that are filtered by predicate.
+  // @param in_row input row.
+  // @param out_predicate result boolean to filter or not.
   // @return Status The status code returned
-  Status WorkerCompute(DataBuffer *in_buffer, std::unique_ptr<TensorQTable> *out);
+  Status WorkerCompute(const TensorRow &in_row, bool *out_predicate);
 
   // Collector databuffer.
   // @return Status The status code returned
@@ -167,14 +167,7 @@ class FilterOp : public ParallelOp {
   // exist in the DataBuffer.
   // @param input_columns The vector of input column names used in the current thread.
   // @return Status The status code returned
-  Status ValidateInColumns(const std::vector<std::string> *input_columns);
-
-  // Private function for checking the column legality
-  // @param in_buf A raw pointer to the DataBuffer. A raw pointer is fine because this function does not manage memory
-  //     and is not shared with other threads.
-  // @param[out] to_process_indices Indices of columns that will feed to predicate.
-  // @param input_columns The vector of input column names used in the current thread.
-  Status CheckColumns(const DataBuffer *in_buf, const std::vector<std::string> *input_columns);
+  Status ValidateInColumns(const std::vector<std::string> &input_columns);
 };
 
 }  // namespace dataset

mindspore/ccsrc/minddata/dataset/engine/datasetops/map_op/map_op.cc

@@ -101,13 +101,12 @@ void MapOp::Print(std::ostream &out, bool show_all) const {
 }
 
 // A helper function that fetch worker map job from local queues and extract the data and map job list
-Status MapOp::FetchNextWork(uint32_t worker_id, std::unique_ptr<DataBuffer> *db,
-                            std::vector<std::shared_ptr<MapJob>> *job_list) {
+Status MapOp::FetchNextWork(uint32_t worker_id, TensorRow *row, std::vector<std::shared_ptr<MapJob>> *job_list) {
   std::unique_ptr<MapWorkerJob> worker_job;
   // Fetch the next worker job and data buffer
   RETURN_IF_NOT_OK(local_queues_[worker_id]->PopFront(&worker_job));
   // Extract the databuffer and job list from the map worker job.
-  *db = std::move(worker_job->databuffer);
+  *row = std::move(worker_job->tensor_row);
   *job_list = std::move(worker_job->jobs);
 
   return Status::OK();
@@ -166,21 +165,22 @@ Status MapOp::operator()() {
 
   RETURN_IF_NOT_OK(callback_manager_.Begin(CallbackParam(0, ep_step, total_step)));
 
-  std::unique_ptr<DataBuffer> buff;
+  child_iterator_ = std::make_unique<ChildIterator>(this, 0, 0);
+  TensorRow new_row;
+  RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
 
-  RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buff, 0));
-  while (!buff->eof()) {
+  while (!new_row.eof()) {
     if (op_current_repeats_ % op_num_repeats_per_epoch() == 0) {
       RETURN_IF_NOT_OK(callback_manager_.EpochBegin(CallbackParam(op_current_epochs_ + 1, ep_step, total_step)));
     }
-    while (!buff->eoe()) {
+    while (!new_row.eoe()) {
       ep_step++;
       total_step++;
       // Create an empty map worker job to be populated by a databuffer and map jobs
 
       RETURN_IF_NOT_OK(callback_manager_.StepBegin(CallbackParam(op_current_epochs_ + 1, ep_step, total_step)));
 
-      std::unique_ptr<MapWorkerJob> worker_job = std::make_unique<MapWorkerJob>(std::move(buff));
+      std::unique_ptr<MapWorkerJob> worker_job = std::make_unique<MapWorkerJob>(std::move(new_row));
 
       // Populate map worker job for a worker to execute
       RETURN_IF_NOT_OK(GenerateWorkerJob(&worker_job));
@@ -190,7 +190,7 @@ Status MapOp::operator()() {
 
       RETURN_IF_NOT_OK(callback_manager_.StepEnd(CallbackParam(op_current_epochs_ + 1, ep_step, total_step)));
 
-      RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buff, 0));
+      RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
     }
 
     // check whether this is the end of a real epoch (not all eoe signals end of epoch)
@@ -200,19 +200,20 @@ Status MapOp::operator()() {
       ep_step = 0;
     }
     // Propagate the eoe buffer to worker
-    std::unique_ptr<MapWorkerJob> worker_job = std::make_unique<MapWorkerJob>(std::move(buff));
+    std::unique_ptr<MapWorkerJob> worker_job = std::make_unique<MapWorkerJob>(std::move(new_row));
     RETURN_IF_NOT_OK(local_queues_[num_buf++ % num_workers_]->Add(std::move(worker_job)));
     UpdateRepeatAndEpochCounter();
-    RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buff, 0));
+    RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
   }
   // End() is commented out because it might never be called due to the lack of EOF when EpochCtrl is -1
   // Handle eof logic, this code might never be reached if epoch_ctrl = -1.
-  std::unique_ptr<MapWorkerJob> worker_job = std::make_unique<MapWorkerJob>(std::move(buff));
+  std::unique_ptr<MapWorkerJob> worker_job = std::make_unique<MapWorkerJob>(std::move(new_row));
   RETURN_IF_NOT_OK(local_queues_[num_buf++ % num_workers_]->Add(std::move(worker_job)));
 
   // Quit all workers, this code might never be reached if EpochCtrl is -1.
   for (int32_t wkr_id = 0; wkr_id < num_workers_; wkr_id++) {
-    auto quit = std::make_unique<MapWorkerJob>(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagQuit));
+    TensorRow quit_flag(TensorRow::kFlagQuit);
+    auto quit = std::make_unique<MapWorkerJob>(quit_flag);
     RETURN_IF_NOT_OK(local_queues_[num_buf++ % num_workers_]->Add(std::move(quit)));
   }
 
@@ -227,78 +228,73 @@ Status MapOp::WorkerEntry(int32_t worker_id) {
   // Handshake with TaskManager that thread creation is successful.
   TaskManager::FindMe()->Post();
 
-  std::unique_ptr<DataBuffer> in_buffer;
+  TensorRow in_row;
   std::vector<std::shared_ptr<MapJob>> job_list;
   // Fetch next data buffer and map job list
-  RETURN_IF_NOT_OK(FetchNextWork(worker_id, &in_buffer, &job_list));
+  RETURN_IF_NOT_OK(FetchNextWork(worker_id, &in_row, &job_list));
 
   // Now that init work is done, drop into the main fetching loop.
   // Map op does not use child iterator, and it needs to manually handle eoe and eof's itself
   // rather than use the base-class defaults.
   while (true) {
     // Handle special logic where buffer carries a ctrl flag.
-    if (in_buffer->buffer_flags() != DataBuffer::kDeBFlagNone) {
-      if (in_buffer->wait()) {
+    if (in_row.Flags() != TensorRow::kFlagNone) {
+      if (in_row.wait()) {
         // When worker receives the signal from master thread, it increments a atomic int
         // The last guy who increments the counter, wakes up master thread
         if (++num_workers_paused_ == num_workers_) {
           wait_for_workers_post_.Set();
         }
         // This will block the worker until master thread gives it a new work
-      } else if (in_buffer->eoe()) {
+      } else if (in_row.eoe()) {
         // Calling base class EoeReceived to forward eoe buffer.
-        RETURN_IF_NOT_OK(EoeReceived(worker_id));
-      } else if (in_buffer->eof()) {
+        RETURN_IF_NOT_OK(out_connector_->SendEOE(worker_id));
+      } else if (in_row.eof()) {
         // Calling base class EofReceived to forward eof buffer.
-        RETURN_IF_NOT_OK(EofReceived(worker_id));
-      } else if (in_buffer->quit()) {
+        RETURN_IF_NOT_OK(out_connector_->SendEOF(worker_id));
+      } else if (in_row.quit()) {
         break;
       }
-      RETURN_IF_NOT_OK(FetchNextWork(worker_id, &in_buffer, &job_list));
+      RETURN_IF_NOT_OK(FetchNextWork(worker_id, &in_row, &job_list));
       continue;
     }
-    CHECK_FAIL_RETURN_UNEXPECTED(in_buffer->NumRows() * in_buffer->NumCols() != 0, "MapOp got an empty DataBuffer.");
-    std::unique_ptr<TensorQTable> new_tensor_table(std::make_unique<TensorQTable>());
+    CHECK_FAIL_RETURN_UNEXPECTED(in_row.size() != 0, "MapOp got an empty TensorRow.");
+    TensorRow out_row;
     // Perform the compute function of TensorOp(s) and store the result in new_tensor_table.
-    RETURN_IF_NOT_OK(WorkerCompute(in_buffer.get(), new_tensor_table.get(), job_list));
+    RETURN_IF_NOT_OK(WorkerCompute(in_row, &out_row, job_list));
     // Replace the TensorTable in DataBuffer with the new one.
-    in_buffer->set_tensor_table(std::move(new_tensor_table));
     // Push the buffer onto the connector for next operator to consume.
-    RETURN_IF_NOT_OK(out_connector_->Add(static_cast<int>(worker_id), std::move(in_buffer)));
+    RETURN_IF_NOT_OK(out_connector_->Add(std::move(out_row), static_cast<int>(worker_id)));
     // Fetch next data buffer and map job list
-    RETURN_IF_NOT_OK(FetchNextWork(worker_id, &in_buffer, &job_list));
+    RETURN_IF_NOT_OK(FetchNextWork(worker_id, &in_row, &job_list));
   }
   return Status::OK();
 }
 
-Status MapOp::WorkerCompute(DataBuffer *in_buffer, TensorQTable *new_tensor_table,
+Status MapOp::WorkerCompute(const TensorRow &in_row, TensorRow *out_row,
                             const std::vector<std::shared_ptr<MapJob>> &job_list) {
-  int32_t num_rows = in_buffer->NumRows();
-  int32_t num_cols = in_buffer->NumCols();
+  int32_t num_cols = in_row.size();
 
   std::vector<TensorRow> job_input_table;
   std::vector<TensorRow> original_table;
-
-  // Prepare the data that we need from in_buffer
-  for (int32_t r = 0; r < num_rows; r++) {
-    // to_process   : A vector of Tensors only holding cols in input_columns.
-    // cur_row      : A vector of Tensors holding all the cols from DataBuffer.
-    TensorRow to_process, cur_row;
-    RETURN_IF_NOT_OK(in_buffer->PopRow(&cur_row));
-    // From the current row, select the Tensor that need to be passed to TensorOp
-    (void)std::transform(to_process_indices_.begin(), to_process_indices_.end(), std::back_inserter(to_process),
-                         [&cur_row](const auto &it) { return std::move(cur_row[it]); });
-    to_process.setId(cur_row.getId());
-    std::vector<std::string> cur_row_path = cur_row.getPath();
-    if (cur_row_path.size() > 0) {
-      std::vector<std::string> to_process_path;
-      (void)std::transform(to_process_indices_.begin(), to_process_indices_.end(), std::back_inserter(to_process_path),
-                           [&cur_row_path](const auto &it) { return cur_row_path[it]; });
-      to_process.setPath(to_process_path);
-    }
-    job_input_table.push_back(std::move(to_process));
-    original_table.push_back(std::move(cur_row));
+  TensorRow to_process;
+  // Prepare the data that we need from in_row
+  // to_process   : A vector of Tensors only holding cols in input_columns.
+  // cur_row      : A vector of Tensors holding all the cols from DataBuffer.
+
+  // From the current row, select the Tensor that need to be passed to TensorOp
+  (void)std::transform(to_process_indices_.begin(), to_process_indices_.end(), std::back_inserter(to_process),
+                       [&in_row](const auto &it) { return std::move(in_row[it]); });
+  to_process.setId(in_row.getId());
+  std::vector<std::string> cur_row_path = in_row.getPath();
+  if (cur_row_path.size() > 0) {
+    std::vector<std::string> to_process_path;
+    (void)std::transform(to_process_indices_.begin(), to_process_indices_.end(), std::back_inserter(to_process_path),
+                         [&cur_row_path](const auto &it) { return cur_row_path[it]; });
+    to_process.setPath(to_process_path);
   }
+  job_input_table.push_back(std::move(to_process));
+  original_table.push_back(std::move(in_row));
 
   // Variable to keep the result after executing the job.
   std::vector<TensorRow> result_table;
@@ -319,26 +315,22 @@ Status MapOp::WorkerCompute(DataBuffer *in_buffer, TensorQTable *new_tensor_tabl
   }
 
   // Merging the data processed by job (result_table) with the data that are not used.
-  for (int32_t r = 0; r < num_rows; r++) {
-    TensorRow out_row;
-    if (in_columns_.size() == out_columns_.size()) {
-      // Place the processed tensor back into the original index of the input tensor
-      for (size_t i = 0; i < result_table[r].size(); i++) {
-        original_table[r][to_process_indices_[i]] = std::move(result_table[r][i]);
-      }
-      out_row = std::move(original_table[r]);
-    } else {
-      // Append the data in the original table that we did not use to the end of each row in result_table.
-      for (int32_t i = 0; i < num_cols; i++) {
-        if (keep_input_columns_[i]) {
-          result_table[r].push_back(std::move(original_table[r][i]));
-        }
+  if (in_columns_.size() == out_columns_.size()) {
+    // Place the processed tensor back into the original index of the input tensor
+    for (size_t i = 0; i < result_table[0].size(); i++) {
+      original_table[0][to_process_indices_[i]] = std::move(result_table[0][i]);
+    }
+    *out_row = std::move(original_table[0]);
+  } else {
+    // Append the data in the original table that we did not use to the end of each row in result_table.
+    for (int32_t i = 0; i < num_cols; i++) {
+      if (keep_input_columns_[i]) {
+        result_table[0].push_back(std::move(original_table[0][i]));
       }
-      out_row = std::move(result_table[r]);
     }
-    // Add this final out_row to our new TensorTable.
-    new_tensor_table->push_back(std::move(out_row));
+    *out_row = std::move(result_table[0]);
   }
+
   return Status::OK();
 }
 
@@ -451,8 +443,8 @@ Status MapOp::WaitForWorkers() {
   num_workers_paused_ = 0;
   for (int32_t wkr_id = 0; wkr_id < num_workers_; wkr_id++) {
     // a special buffer (id=-1, empty, none flag) is used to signal that worker needs to pause.
-    RETURN_IF_NOT_OK(local_queues_[wkr_id]->Add(
-      std::make_unique<MapWorkerJob>(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagWait))));
+    TensorRow waitRow(TensorRow::kFlagWait);
+    RETURN_IF_NOT_OK(local_queues_[wkr_id]->Add(std::make_unique<MapWorkerJob>(waitRow)));
   }
   // wait until all workers are done processing their work in local_queue_
   RETURN_IF_NOT_OK(wait_for_workers_post_.Wait());

mindspore/ccsrc/minddata/dataset/engine/datasetops/map_op/map_op.h

@@ -24,6 +24,7 @@
 #include <vector>
 
 #include "minddata/dataset/callback/ds_callback.h"
+#include "minddata/dataset/engine/dataset_iterator.h"
 #include "minddata/dataset/engine/datasetops/map_op/map_job.h"
 #include "minddata/dataset/engine/datasetops/parallel_op.h"
 #include "minddata/dataset/kernels/tensor_op.h"
@@ -192,17 +193,16 @@ class MapOp : public ParallelOp {
   // A unit of job for map worker thread.
   // MapWorkerJob holds a list of MapJob where each MapJob can be a CpuMapJob, GpuMapJob or DvppMapJob.
   struct MapWorkerJob {
-    explicit MapWorkerJob(std::unique_ptr<DataBuffer> db) : databuffer(std::move(db)) {}
+    explicit MapWorkerJob(TensorRow tr) : tensor_row(std::move(tr)) {}
     std::vector<std::shared_ptr<MapJob>> jobs;
-    std::unique_ptr<DataBuffer> databuffer;
+    TensorRow tensor_row;
   };
 
   // A helper function to create jobs for workers.
   Status GenerateWorkerJob(const std::unique_ptr<MapWorkerJob> *worker_job);
 
   // A helper function that fetch worker map job from local queues and extract the data and map job list
-  Status FetchNextWork(uint32_t worker_id, std::unique_ptr<DataBuffer> *db,
-                       std::vector<std::shared_ptr<MapJob>> *job_list);
+  Status FetchNextWork(uint32_t worker_id, TensorRow *row, std::vector<std::shared_ptr<MapJob>> *job_list);
 
   // Local queues where worker threads get a job from
   QueueList<std::unique_ptr<MapWorkerJob>> local_queues_;
@@ -222,6 +222,8 @@ class MapOp : public ParallelOp {
   // Indices of the columns to process.
   std::vector<size_t> to_process_indices_;
 
+  std::unique_ptr<ChildIterator> child_iterator_;  // An iterator for fetching.
+
   // Private function for worker/thread to loop continuously. It comprises the main
   // logic of MapOp: getting the data from previous Op, validating user specified column names,
   // applying a list of TensorOps to each of the data, process the results and then
@@ -234,7 +236,7 @@ class MapOp : public ParallelOp {
   // @param in_buffer A raw pointer to the DataBuffer. A raw pointer is fine because this function doesn't manage memory
   //     and is not shared with other threads.
   // @param[out] new_tensor_table A new Tensor Table to be populated in this function.
-  Status WorkerCompute(DataBuffer *in_buffer, TensorQTable *new_tensor_table,
+  Status WorkerCompute(const TensorRow &in_row, TensorRow *out_row,
                        const std::vector<std::shared_ptr<MapJob>> &job_list);
 
   // Private function that create the final column name to index mapping and

mindspore/ccsrc/minddata/dataset/engine/datasetops/project_op.cc

@@ -67,32 +67,25 @@ void ProjectOp::Print(std::ostream &out, bool show_all) const {
 }
 
 // Gets a buffer from the child operator and projects the buffer.
-Status ProjectOp::GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id, bool retry_if_eoe) {
-  RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(p_buffer, worker_id, retry_if_eoe));
-  if (!((*p_buffer)->eoe()) && !((*p_buffer)->eof())) {
-    RETURN_IF_NOT_OK(Project(p_buffer));
+Status ProjectOp::GetNextRow(TensorRow *row, int32_t worker_id, bool retry_if_eoe) {
+  RETURN_IF_NOT_OK(child_[0]->GetNextRow(row, worker_id, retry_if_eoe));
+  if (!row->eoe() && !row->eof()) {
+    *row = Project(*row);
   }
-  if ((*p_buffer)->eoe()) {
+  if (row->eoe()) {
     UpdateRepeatAndEpochCounter();
   }
   return Status::OK();
 }
 
-Status ProjectOp::Project(std::unique_ptr<DataBuffer> *data_buffer) {
-  std::unique_ptr<TensorQTable> new_tensor_table = std::make_unique<TensorQTable>();
-  while ((*data_buffer)->NumRows() > 0) {
-    TensorRow current_row;
-    RETURN_IF_NOT_OK((*data_buffer)->PopRow(&current_row));
-    TensorRow new_row;
-    (void)std::transform(projected_column_indices_.begin(), projected_column_indices_.end(),
-                         std::back_inserter(new_row), [&current_row](uint32_t x) { return current_row[x]; });
-    // Now if columns changed after map, we don't know which column we should keep,
-    // so temporarily we don't support print file_path after ProjectOp.
-    new_row.setPath({});
-    new_tensor_table->push_back(new_row);
-  }
-  (*data_buffer)->set_tensor_table(std::move(new_tensor_table));
-  return Status::OK();
+TensorRow ProjectOp::Project(const TensorRow &row) {
+  TensorRow new_row;
+  (void)std::transform(projected_column_indices_.begin(), projected_column_indices_.end(), std::back_inserter(new_row),
+                       [&row](uint32_t x) { return row[x]; });
+  // Now if columns changed after map, we don't know which column we should keep,
+  // so temporarily we don't support print file_path after ProjectOp.
+  new_row.setPath({});
+  return new_row;
 }
 
 // Class functor operator () override.
@@ -152,10 +145,10 @@ Status ProjectOp::ComputeColMap() {
   return Status::OK();
 }
 
-Status ProjectOp::GetNextRow(TensorRow *row) {
+Status ProjectOp::GetNextRowPullMode(TensorRow *row) {
   ComputeColMap();
   TensorRow new_row;
-  RETURN_IF_NOT_OK(child_[0]->GetNextRow(&new_row));
+  RETURN_IF_NOT_OK(child_[0]->GetNextRowPullMode(&new_row));
   (void)std::transform(projected_column_indices_.begin(), projected_column_indices_.end(), std::back_inserter(*row),
                        [&new_row](uint32_t x) { return new_row[x]; });
   // Now if columns changed after map, we don't know which column we should keep,

mindspore/ccsrc/minddata/dataset/engine/datasetops/project_op.h

@@ -81,7 +81,7 @@ class ProjectOp : public PipelineOp {
   // Gets a buffer from the child node and projects that buffer. The caller is typically our parent node.
   // @param p_buffer - output pointer to the projected buffer.
   // @param worker_id - The worker id
-  Status GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id, bool retry_if_eoe) override;
+  Status GetNextRow(TensorRow *row, int32_t worker_id, bool retry_if_eoe) override;
 
   // Base-class override. Return the number of workers in the first parent.
   // @param workerId - The worker id
@@ -101,7 +101,7 @@ class ProjectOp : public PipelineOp {
   // @return Status The status code returned
   Status EofReceived(int32_t worker_id) override;
 
-  Status GetNextRow(TensorRow *row) override;
+  Status GetNextRowPullMode(TensorRow *row) override;
 
   // Op name getter
   // @return Name of the current Op
@@ -111,7 +111,7 @@ class ProjectOp : public PipelineOp {
   std::vector<std::string> columns_to_project_;
   std::vector<int32_t> projected_column_indices_;
 
-  Status Project(std::unique_ptr<DataBuffer> *data_buffer);
+  TensorRow Project(const TensorRow &row);
 
   // Computing the assignment of the column name map.
   // @return - Status

mindspore/ccsrc/minddata/dataset/engine/datasetops/rename_op.cc

@@ -59,32 +59,24 @@ RenameOp::~RenameOp() {}
 // main entry point for rename
 Status RenameOp::operator()() {
   TaskManager::FindMe()->Post();
-  std::unique_ptr<DataBuffer> curr_buffer;
-  RETURN_IF_NOT_OK(GetNextInput(&curr_buffer));
-  if (curr_buffer->buffer_flags() != DataBuffer::kDeBFlagNone) {
-    RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(curr_buffer)));
-    std::string err_msg = "Rename first buffer got was control signal";
-    // if 1st eoe or eof, pass it on then return
-    RETURN_STATUS_UNEXPECTED(err_msg);
-  }
+  child_iterator_ = std::make_unique<ChildIterator>(this, 0, 0);
 
-  while (curr_buffer->eof() == false) {
-    while (curr_buffer->eoe() == false) {
-      // push the renamed input buffer
-      MS_LOG(DEBUG) << "Rename operator pushing next buffer.";
-      RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(curr_buffer)));
-      RETURN_IF_NOT_OK(GetNextInput(&curr_buffer));
-    }  // end of while eoe loop
+  TensorRow new_row;
+  RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
 
-    // we got eoe, now try again until we get eof
+  while (!new_row.eof()) {
+    while (!new_row.eoe()) {
+      MS_LOG(DEBUG) << "Rename operator pushing next buffer.";
+      RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row)));
+      RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
+    }
+    RETURN_IF_NOT_OK(out_connector_->SendEOE());
     MS_LOG(DEBUG) << "Rename operator EOE Received.";
-    RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE))));
+    RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
     MS_LOG(DEBUG) << "Rename operator fetching buffer after EOE.";
-    RETURN_IF_NOT_OK(GetNextInput(&curr_buffer));
-  }  // end of while eof loop
-
-  MS_LOG(DEBUG) << "Rename opeerator EOF Received.";
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF))));
+  }
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
+  MS_LOG(DEBUG) << "Rename operator EOF Received.";
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/rename_op.h

@@ -21,6 +21,7 @@
 #include <string>
 #include <vector>
 #include "minddata/dataset/core/tensor.h"
+#include "minddata/dataset/engine/dataset_iterator.h"
 #include "minddata/dataset/engine/datasetops/pipeline_op.h"
 #include "minddata/dataset/util/status.h"
 
@@ -125,6 +126,8 @@ class RenameOp : public PipelineOp {
 
   // Variable to store the output column names
   std::vector<std::string> out_columns_;
+
+  std::unique_ptr<ChildIterator> child_iterator_;  // An iterator for fetching.
 };
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/engine/datasetops/repeat_op.cc

@@ -78,27 +78,24 @@ void RepeatOp::Print(std::ostream &out, bool show_all) const {
 // a buffer from our child.
 // This function sets the `retryIfEoe` flag when popping from the child connector. This way,
 // this function will retry to pop the connector again and will get the non-EOE buffer if any.
-Status RepeatOp::GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id, bool retry_if_eoe) {
+Status RepeatOp::GetNextRow(TensorRow *row, int32_t worker_id, bool retry_if_eoe) {
   if (child_.empty()) {
     RETURN_STATUS_UNEXPECTED("Pipeline init failed, RepeatOp can't be the first op in pipeline.");
   }
 
-  std::unique_ptr<DataBuffer> buf;
-  RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buf, worker_id, true));
+  RETURN_IF_NOT_OK(child_[0]->GetNextRow(row, worker_id, true));
   // Loop until non EOE is received
-  while (buf->eoe()) {
+  while (row->eoe()) {
     RETURN_IF_NOT_OK(EoeReceived(worker_id));
     if (state_ == OpState::kDeOpIdle) {
-      *p_buffer = std::move(buf);
       return Status::OK();
     }
-    RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buf, worker_id, true));
+    RETURN_IF_NOT_OK(child_[0]->GetNextRow(row, worker_id, true));
   }
   // Check if the last buf is next eof
-  if (buf->eof()) {
+  if (row->eof()) {
     RETURN_IF_NOT_OK(EofReceived(worker_id));
   }
-  *p_buffer = std::move(buf);
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/repeat_op.h

@@ -91,7 +91,7 @@ class RepeatOp : public PipelineOp {
   // @param worker_id - The worker id
   // @param retry_if_eoe Set this flag to true to allow calling pop() again after the first pop() returns EOE.
   // @return Status The status code returned
-  Status GetNextBuffer(std::unique_ptr<DataBuffer> *p_buffer, int32_t worker_id, bool retry_if_eoe) override;
+  Status GetNextRow(TensorRow *row, int32_t worker_id, bool retry_if_eoe) override;
 
   // Base-class override for handling cases when an eoe is received.
   // @param worker_id - The worker id

mindspore/ccsrc/minddata/dataset/engine/datasetops/shuffle_op.cc

@@ -152,6 +152,7 @@ Status ShuffleOp::operator()() {
 
     // This is our main loop exit condition, when the iterator has no more data completely.
     if (child_iterator_->eof_handled()) {
+      RETURN_IF_NOT_OK(out_connector_->SendEOF());
       break;
     }
 
@@ -170,21 +171,11 @@ Status ShuffleOp::operator()() {
       // tensor table. We remove the data from the shuffle buffer, leaving that slot
       // in the table as an empty vector
       int64_t random_slot = rng_() % (shuffle_last_row_idx_ + 1);
-      new_buffer_table->push_back(std::move((*shuffle_buffer_)[random_slot]));
+      TensorRow random_row = std::move((*shuffle_buffer_)[random_slot]);
+      MS_LOG(DEBUG) << "Shuffle operator sending a row to output.";
+      RETURN_IF_NOT_OK(out_connector_->Add(std::move(random_row)));
 
       // Step 3)
-      // If the output tensor table is at the requested size, then create a buffer for it
-      // and send this buffer on it's way up the pipeline. Special case is if this is the
-      // last row then we also send it.
-      if (new_buffer_table->size() == rows_per_buffer_ || shuffle_last_row_idx_ == 0) {
-        auto new_buffer = std::make_unique<DataBuffer>(buffer_counter_, DataBuffer::kDeBFlagNone);
-        new_buffer->set_tensor_table(std::move(new_buffer_table));
-        buffer_counter_++;
-        MS_LOG(DEBUG) << "Shuffle operator sending a buffer to output.";
-        RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(new_buffer)));
-      }
-
-      // Step 4)
       // Take the last row from shuffle buffer, and swap it into the row position that was
       // just vacated.  This makes the shuffle buffer contiguous, with an empty slot at the
       // tail of the shuffle buffer.
@@ -192,7 +183,7 @@ Status ShuffleOp::operator()() {
         (*shuffle_buffer_)[random_slot] = std::move((*shuffle_buffer_)[shuffle_last_row_idx_]);
       }
 
-      // Step 5)
+      // Step 4)
       // Refill the last slot of the shuffle buffer with the next row from input if we are in the
       // active state.
       // If we are in the draining state, we do not need to fetch another row to replace the one we
@@ -218,14 +209,14 @@ Status ShuffleOp::operator()() {
     // Since we overloaded eoeReceived function, we are responsible to flow the EOE up the
     // pipeline manually now that we are done draining the shuffle buffer
     MS_LOG(DEBUG) << "Shuffle operator sending EOE.";
-    auto eoe_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE);
-    RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(eoe_buffer)));
+    RETURN_IF_NOT_OK(out_connector_->SendEOE());
 
     // Do not wait for any reset to be flown down from operators above us.
     // Instead, manually update ourselves and then go reloop to start fetching from child operator
     // right away.  Any Reset() from the parent will still perform common reset actions.
     RETURN_IF_NOT_OK(this->SelfReset());
   }
+
   return Status::OK();
 }
 
@@ -252,6 +243,7 @@ Status ShuffleOp::InitShuffleBuffer() {
 
   if (child_iterator_->eof_handled()) {
     MS_LOG(DEBUG) << "Shuffle operator init picked up EOF. No more epochs.";
+    RETURN_IF_NOT_OK(out_connector_->SendEOF());
     return Status::OK();
   }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/skip_op.cc

@@ -19,9 +19,9 @@
 
 #include "minddata/dataset/core/config_manager.h"
 #include "minddata/dataset/engine/data_buffer.h"
+#include "minddata/dataset/engine/dataset_iterator.h"
 #include "minddata/dataset/engine/datasetops/skip_op.h"
 #include "minddata/dataset/engine/db_connector.h"
-#include "minddata/dataset/engine/execution_tree.h"
 #include "minddata/dataset/util/log_adapter.h"
 
 namespace mindspore {
@@ -69,57 +69,32 @@ void SkipOp::Print(std::ostream &out, bool show_all) const {
   }
 }
 
-// Base-class override for handling cases when an eoe is received.
-Status SkipOp::EoeReceived(int32_t worker_id) {
-  skip_count_ = 0;
-  state_ = OpState::kDeOpIdle;
-  return Status::OK();
-}
-
 // main entry point for skip
 Status SkipOp::operator()() {
   TaskManager::FindMe()->Post();
-  std::unique_ptr<DataBuffer> curr_buffer;
-  RETURN_IF_NOT_OK(GetNextInput(&curr_buffer));
+  child_iterator_ = std::make_unique<ChildIterator>(this, 0, 0);
 
-  while (curr_buffer->eof() == false) {
+  TensorRow new_row;
+  RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
+  while (!new_row.eof()) {
     // Reset count
     skip_count_ = 0;
-    while (curr_buffer->eoe() == false) {
+    while (!new_row.eoe()) {
       // Drop first count rows
-      while (skip_count_ < max_skips_) {
-        if (curr_buffer->eoe() || curr_buffer->eof()) {
-          break;
-        }
-        // Consider the rows of buffer more than one
-        TensorRow drop_row;
-        int row_num = curr_buffer->NumRows();
-        int drop_num = row_num + skip_count_ < max_skips_ ? row_num : max_skips_ - skip_count_;
-        skip_count_ += drop_num;
-        for (int i = 0; i < drop_num; i++) {
-          RETURN_IF_NOT_OK(curr_buffer->PopRow(&drop_row));
-        }
-        if (curr_buffer->NumRows() == 0) {
-          RETURN_IF_NOT_OK(GetNextInput(&curr_buffer));
-        }
+      if (skip_count_ < max_skips_) {
+        skip_count_++;
+      } else {
+        RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row)));
       }
-      RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(curr_buffer)));
-      RETURN_IF_NOT_OK(GetNextInput(&curr_buffer));
+      RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
     }
     // we got eoe, now try again until we got eof
     MS_LOG(DEBUG) << "Skip operator EOE Received.";
-    RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE))));
-    RETURN_IF_NOT_OK(GetNextInput(&curr_buffer));
+    RETURN_IF_NOT_OK(out_connector_->SendEOE());
+    RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
   }
-
   MS_LOG(DEBUG) << "Skip operator EOF Received.";
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF))));
-  return Status::OK();
-}
-
-// Base-class override for handling cases when an eof is received.
-Status SkipOp::EofReceived(int32_t worker_id) {
-  MS_LOG(DEBUG) << "Skip operator EOF received, do nothing now.";
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/skip_op.h

@@ -66,14 +66,6 @@ class SkipOp : public PipelineOp {
   // @return Status The status code returned
   Status operator()() override;
 
-  // Base-class override for handling cases when an eoe is received.
-  // @param worker_id - The worker id
-  Status EoeReceived(int32_t worker_id) override;
-
-  // Base-class override for handling cases when an eof is received.
-  // @param worker_id - The worker id
-  Status EofReceived(int32_t worker_id) override;
-
   // Op name getter
   // @return Name of the current Op
   std::string Name() const override { return kSkipOp; }
@@ -81,6 +73,8 @@ class SkipOp : public PipelineOp {
  private:
   int32_t max_skips_;   // The number of skips that the user requested
   int32_t skip_count_;  // A counter for the current number of executed skips
+
+  std::unique_ptr<ChildIterator> child_iterator_;  // An iterator for fetching.
 };
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/album_op.cc

@@ -485,7 +485,7 @@ Status AlbumOp::ComputeColMap() {
   return Status::OK();
 }
 
-Status AlbumOp::GetNextRow(TensorRow *row) {
+Status AlbumOp::GetNextRowPullMode(TensorRow *row) {
   if (image_rows_.empty()) PrescanEntry();
   if (sample_ids_ == nullptr) {
     RETURN_IF_NOT_OK(this->InitSampler());

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/album_op.h

@@ -267,7 +267,7 @@ class AlbumOp : public MappableLeafOp {
   /// \return Status The status code returned
   Status LaunchThreadsAndInitOp() override;
 
-  Status GetNextRow(TensorRow *row) override;
+  Status GetNextRowPullMode(TensorRow *row) override;
 
   /// Private function for computing the assignment of the column name map.
   /// \return Status The status code returned

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/clue_op.cc

@@ -145,11 +145,8 @@ Status ClueOp::LoadFile(const std::string &file, int64_t start_offset, int64_t e
     RETURN_STATUS_UNEXPECTED("Invalid file, failed to open file: " + file);
   }
 
-  int64_t rows_each_buffer = 0;
   int64_t rows_total = 0;
   std::string line;
-  std::unique_ptr<DataBuffer> cur_buffer = std::make_unique<DataBuffer>(0, DataBuffer::BufferFlags::kDeBFlagNone);
-  std::unique_ptr<TensorQTable> tensor_table = std::make_unique<TensorQTable>();
 
   while (getline(handle, line)) {
     if (line.empty()) {
@@ -177,31 +174,18 @@ Status ClueOp::LoadFile(const std::string &file, int64_t start_offset, int64_t e
     // Add file path info
     std::vector<std::string> file_path(cols_count, file);
     tRow.setPath(file_path);
-    tensor_table->push_back(std::move(tRow));
     int cout = 0;
     for (auto &p : cols_to_keyword_) {
       std::shared_ptr<Tensor> tensor;
       RETURN_IF_NOT_OK(GetValue(js, p.second, &tensor));
-      (*tensor_table)[rows_each_buffer][cout] = std::move(tensor);
+      tRow[cout] = std::move(tensor);
       cout++;
     }
 
-    rows_each_buffer++;
     rows_total++;
-    if (rows_each_buffer == rows_per_buffer_) {
-      cur_buffer->set_tensor_table(std::move(tensor_table));
-      RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(cur_buffer)));
-
-      cur_buffer = std::make_unique<DataBuffer>(0, DataBuffer::BufferFlags::kDeBFlagNone);
-      tensor_table = std::make_unique<TensorQTable>();
-      rows_each_buffer = 0;
-    }
+    RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(tRow)));
   }
 
-  if (rows_each_buffer > 0) {
-    cur_buffer->set_tensor_table(std::move(tensor_table));
-    RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(cur_buffer)));
-  }
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/csv_op.cc

@@ -101,20 +101,17 @@ CsvOp::CsvParser::CsvParser(int32_t worker_id, JaggedConnector *connector, int64
       file_path_(file_path),
       cur_state_(START_OF_FILE),
       pos_(0),
-      cur_row_(0),
       cur_col_(0),
       total_rows_(0),
       start_offset_(0),
       end_offset_(std::numeric_limits<int64_t>::max()),
       err_message_("unknown") {
-  cur_buffer_ = std::make_unique<DataBuffer>(0, DataBuffer::BufferFlags::kDeBFlagNone);
   InitCsvParser();
 }
 
 void CsvOp::CsvParser::Reset() {
   cur_state_ = START_OF_FILE;
   pos_ = 0;
-  cur_row_ = 0;
   cur_col_ = 0;
 }
 
@@ -170,11 +167,11 @@ int CsvOp::CsvParser::PutRecord(int c) {
       Tensor::CreateScalar(s, &t);
       break;
   }
-  if (cur_col_ >= (*tensor_table_)[cur_row_].size()) {
+  if (cur_col_ >= cur_row_.size()) {
     err_message_ = "Number of file columns does not match the tensor table";
     return -1;
   }
-  (*tensor_table_)[cur_row_][cur_col_] = std::move(t);
+  cur_row_[cur_col_] = std::move(t);
   pos_ = 0;
   cur_col_++;
   return 0;
@@ -203,18 +200,10 @@ int CsvOp::CsvParser::PutRow(int c) {
   }
 
   total_rows_++;
-  cur_row_++;
   cur_col_ = 0;
 
-  if (cur_row_ == csv_rows_per_buffer_) {
-    cur_buffer_->set_tensor_table(std::move(tensor_table_));
+  buffer_connector_->Add(worker_id_, std::move(cur_row_));
 
-    buffer_connector_->Add(worker_id_, std::move(cur_buffer_));
-
-    cur_buffer_ = std::make_unique<DataBuffer>(0, DataBuffer::BufferFlags::kDeBFlagNone);
-    tensor_table_ = std::make_unique<TensorQTable>();
-    cur_row_ = 0;
-  }
   return 0;
 }
 
@@ -230,11 +219,6 @@ int CsvOp::CsvParser::EndFile(int c) {
       return ret;
     }
   }
-
-  if (cur_row_ > 0) {
-    cur_buffer_->set_tensor_table(std::move(tensor_table_));
-    buffer_connector_->Add(worker_id_, std::move(cur_buffer_));
-  }
   return 0;
 }
 
@@ -345,8 +329,7 @@ Status CsvOp::CsvParser::InitCsvParser() {
             TensorRow row(column_default_.size(), nullptr);
             std::vector<std::string> file_path(column_default_.size(), file_path_);
             row.setPath(file_path);
-            this->tensor_table_ = std::make_unique<TensorQTable>();
-            this->tensor_table_->push_back(row);
+            this->cur_row_ = std::move(row);
             this->str_buf_[0] = c;
             this->pos_ = 1;
             return 0;
@@ -357,8 +340,7 @@ Status CsvOp::CsvParser::InitCsvParser() {
             TensorRow row(column_default_.size(), nullptr);
             std::vector<std::string> file_path(column_default_.size(), file_path_);
             row.setPath(file_path);
-            this->tensor_table_ = std::make_unique<TensorQTable>();
-            this->tensor_table_->push_back(row);
+            this->cur_row_ = std::move(row);
             return this->PutRecord(c);
           }}},
         {{State::START_OF_FILE, Message::MS_QUOTE},
@@ -367,8 +349,7 @@ Status CsvOp::CsvParser::InitCsvParser() {
             TensorRow row(column_default_.size(), nullptr);
             std::vector<std::string> file_path(column_default_.size(), file_path_);
             row.setPath(file_path);
-            this->tensor_table_ = std::make_unique<TensorQTable>();
-            this->tensor_table_->push_back(row);
+            this->cur_row_ = std::move(row);
             this->pos_ = 0;
             return 0;
           }}},
@@ -454,7 +435,7 @@ Status CsvOp::CsvParser::InitCsvParser() {
               TensorRow row(column_default_.size(), nullptr);
               std::vector<std::string> file_path(column_default_.size(), file_path_);
               row.setPath(file_path);
-              this->tensor_table_->push_back(row);
+              this->cur_row_ = std::move(row);
             }
             this->str_buf_[0] = c;
             this->pos_ = 1;
@@ -467,7 +448,7 @@ Status CsvOp::CsvParser::InitCsvParser() {
               TensorRow row(column_default_.size(), nullptr);
               std::vector<std::string> file_path(column_default_.size(), file_path_);
               row.setPath(file_path);
-              this->tensor_table_->push_back(row);
+              this->cur_row_ = std::move(row);
             }
             return this->PutRecord(c);
           }}},
@@ -478,7 +459,7 @@ Status CsvOp::CsvParser::InitCsvParser() {
               TensorRow row(column_default_.size(), nullptr);
               std::vector<std::string> file_path(column_default_.size(), file_path_);
               row.setPath(file_path);
-              this->tensor_table_->push_back(row);
+              this->cur_row_ = std::move(row);
             }
             return 0;
           }}},

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/csv_op.h

@@ -133,7 +133,6 @@ class CsvOp : public NonMappableLeafOp {
     std::vector<std::shared_ptr<CsvOp::BaseRecord>> column_default_;
     State cur_state_;
     size_t pos_;
-    int cur_row_;
     int cur_col_;
     int64_t total_rows_;
     int64_t start_offset_;
@@ -141,8 +140,7 @@ class CsvOp : public NonMappableLeafOp {
     StateDiagram sd;
     StateDiagram sdl;
     std::vector<char> str_buf_;
-    std::unique_ptr<TensorQTable> tensor_table_;
-    std::unique_ptr<DataBuffer> cur_buffer_;
+    TensorRow cur_row_;
     std::string err_message_;
     std::string file_path_;
   };

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/generator_op.cc

@@ -41,19 +41,18 @@ Status GeneratorOp::Builder::SanityCheck() {
 Status GeneratorOp::Builder::Build(std::shared_ptr<GeneratorOp> *ptr) {
   RETURN_IF_NOT_OK(SanityCheck());
   *ptr = std::make_shared<GeneratorOp>(build_generator_function_, build_column_names_, build_column_types_,
-                                       build_prefetch_size_, build_buffer_size_, build_op_connector_size_, nullptr);
+                                       build_prefetch_size_, build_op_connector_size_, nullptr);
   return (*ptr)->Init();
 }
 
 GeneratorOp::GeneratorOp(py::function generator_function, std::vector<std::string> column_names,
-                         std::vector<DataType> column_types, int32_t prefetch_size, int32_t buffer_size,
-                         int32_t connector_size, std::shared_ptr<SamplerRT> sampler)
+                         std::vector<DataType> column_types, int32_t prefetch_size, int32_t connector_size,
+                         std::shared_ptr<SamplerRT> sampler)
     : PipelineOp(connector_size, std::move(sampler)),
       generator_function_(generator_function),
       column_names_(column_names),
       column_types_(column_types),
       prefetch_size_(prefetch_size),
-      buffer_size_(buffer_size),
       buffer_id_(0),
       generator_counter_(0) {}
 
@@ -145,16 +144,6 @@ Status GeneratorOp::PyRowToTensorRow(py::object py_data, TensorRow *tensor_row)
   return Status(StatusCode::kSuccess, "");
 }
 
-Status GeneratorOp::FillBuffer(TensorQTable *tt) {
-  for (int i = 0; i < buffer_size_; i++) {
-    TensorRow row;
-    RETURN_IF_NOT_OK(PyRowToTensorRow(generator_.attr("__next__")(), &row));
-    tt->push_back(std::move(row));
-    generator_counter_++;
-  }
-  return Status::OK();
-}
-
 // Entry point for Generator, called by launch()
 // Note that this function is very easy to break because of the Python GIL mechanism
 // The master thread has the following workflow
@@ -192,23 +181,22 @@ Status GeneratorOp::operator()() {
   // Handshake with TaskManager to synchronize thread creation
   TaskManager::FindMe()->Post();
   RETURN_IF_NOT_OK(wp_.Register(tree_->AllTasks()));
-  std::unique_ptr<DataBuffer> fetched_buffer;
   int64_t num_rows_sampled = sampler_ ? sampler_->CalculateNumSamples(num_rows_) : num_rows_;
   RETURN_IF_NOT_OK(Init());
 
   bool eof = false;
   while (!eof) {
-    // Create new buffer each iteration
-    fetched_buffer = std::make_unique<DataBuffer>(buffer_id_++, DataBuffer::kDeBFlagNone);
-    std::unique_ptr<TensorQTable> fetched_table = std::make_unique<TensorQTable>();
+    // Create new row each iteration
     bool eoe = false;
+    TensorRow new_row;
     {
       py::gil_scoped_acquire gil_acquire;
       if (Py_IsInitialized() == 0) {
         return Status(StatusCode::kMDPythonInterpreterFailure, "Python Interpreter is finalized");
       }
       try {
-        RETURN_IF_NOT_OK(FillBuffer(fetched_table.get()));
+        RETURN_IF_NOT_OK(PyRowToTensorRow(generator_.attr("__next__")(), &new_row));
+        generator_counter_++;
       } catch (py::error_already_set &e) {
         eoe = e.matches(PyExc_StopIteration);
         // Restore exception to python
@@ -226,20 +214,18 @@ Status GeneratorOp::operator()() {
         }
       }
     }
-    if (fetched_table->size() > 0) {
-      fetched_buffer->set_tensor_table(std::move(fetched_table));
-      RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(fetched_buffer)));
-    }
+    if (!new_row.empty()) RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row)));
+
     if (eoe) {
       // Push out EOE upon StopIteration exception from generator
       MS_LOG(DEBUG) << "Generator operator sends out EOE.";
       std::unique_ptr<DataBuffer> eoe_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE);
-      RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(eoe_buffer)));
+      RETURN_IF_NOT_OK(out_connector_->SendEOE());
       if (IsLastIteration()) {
         // If last repeat or not repeated, push out EOF and exit master loop
         MS_LOG(DEBUG) << "Generator operator sends out EOF.";
         std::unique_ptr<DataBuffer> eof_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF);
-        RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(eof_buffer)));
+        RETURN_IF_NOT_OK(out_connector_->SendEOF());
         MS_LOG(DEBUG) << "Generator operator main execution loop complete.";
         eof = true;
       } else {

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/generator_op.h

@@ -94,7 +94,7 @@ class GeneratorOp : public PipelineOp, public RandomAccessOp {
   };
 
   GeneratorOp(py::function generator_function, std::vector<std::string> column_names,
-              std::vector<DataType> column_types, int32_t prefetch_size, int32_t buffer_size, int32_t connector_size,
+              std::vector<DataType> column_types, int32_t prefetch_size, int32_t connector_size,
               std::shared_ptr<SamplerRT> sampler);
 
   ~GeneratorOp() = default;
@@ -135,7 +135,6 @@ class GeneratorOp : public PipelineOp, public RandomAccessOp {
   std::vector<std::string> column_names_;
   std::vector<DataType> column_types_;
   int32_t prefetch_size_;
-  int32_t buffer_size_;
   int64_t generator_counter_;
 
   py::object generator_;

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/mappable_leaf_op.cc

@@ -14,11 +14,9 @@
  * limitations under the License.
  */
 #include "minddata/dataset/engine/datasetops/source/mappable_leaf_op.h"
-#include <fstream>
 #include <unordered_set>
 #include "utils/ms_utils.h"
 #include "minddata/dataset/core/config_manager.h"
-#include "minddata/dataset/core/tensor_shape.h"
 #include "minddata/dataset/engine/datasetops/source/sampler/sequential_sampler.h"
 #include "minddata/dataset/engine/db_connector.h"
 #include "minddata/dataset/engine/execution_tree.h"
@@ -28,44 +26,34 @@ namespace dataset {
 
 MappableLeafOp::MappableLeafOp(int32_t num_wkrs, int32_t queue_size, std::shared_ptr<SamplerRT> sampler,
                                int32_t rows_per_buffer)
-    : ParallelOp(num_wkrs, queue_size, std::move(sampler)),
-      row_cnt_(0),
-      buf_cnt_(0),
-      rows_per_buffer_(rows_per_buffer) {}
+    : ParallelOp(num_wkrs, queue_size, std::move(sampler)), rows_per_buffer_(rows_per_buffer) {}
 
 // Main logic, Register Queue with TaskGroup, launch all threads and do the functor's work
 Status MappableLeafOp::operator()() {
   RETURN_IF_NOT_OK(LaunchThreadsAndInitOp());
   std::unique_ptr<DataBuffer> sampler_buffer;
   RETURN_IF_NOT_OK(sampler_->GetNextSample(&sampler_buffer));
-  while (true) {  // each iterator is 1 epoch
-    std::vector<int64_t> keys;
-    keys.reserve(rows_per_buffer_);
+  int64_t row_cnt = 0;
+  while (true) {  // each iteration is 1 epoch, breaks when IsLastIteration() is true
     while (sampler_buffer->eoe() == false) {
       TensorRow sample_row;
       RETURN_IF_NOT_OK(sampler_buffer->PopRow(&sample_row));
       std::shared_ptr<Tensor> sample_ids = sample_row[0];
       for (auto itr = sample_ids->begin<int64_t>(); itr != sample_ids->end<int64_t>(); ++itr) {
-        if ((*itr) >= num_rows_) continue;  // index out of bound, skipping
-        keys.push_back(*itr);
-        row_cnt_++;
-        if (row_cnt_ % rows_per_buffer_ == 0) {
-          RETURN_IF_NOT_OK(
-            io_block_queues_[buf_cnt_++ % num_workers_]->Add(std::make_unique<IOBlock>(keys, IOBlock::kDeIoBlockNone)));
-          keys.clear();
+        if ((*itr) >= num_rows_) {
+          MS_LOG(WARNING) << "Skipping sample with ID: " << *itr << " since it is out of bound: " << num_rows_;
+          continue;  // index out of bound, skipping
         }
+        RETURN_IF_NOT_OK(
+          io_block_queues_[row_cnt++ % num_workers_]->Add(std::make_unique<IOBlock>(*itr, IOBlock::kDeIoBlockNone)));
       }
       RETURN_IF_NOT_OK(sampler_->GetNextSample(&sampler_buffer));
     }
-    if (keys.empty() == false) {
-      RETURN_IF_NOT_OK(
-        io_block_queues_[(buf_cnt_++) % num_workers_]->Add(std::make_unique<IOBlock>(keys, IOBlock::kDeIoBlockNone)));
-    }
     if (IsLastIteration()) {
       std::unique_ptr<IOBlock> eoe_block = std::make_unique<IOBlock>(IOBlock::kDeIoBlockFlagEoe);
       std::unique_ptr<IOBlock> eof_block = std::make_unique<IOBlock>(IOBlock::kDeIoBlockFlagEof);
-      RETURN_IF_NOT_OK(io_block_queues_[(buf_cnt_++) % num_workers_]->Add(std::move(eoe_block)));
-      RETURN_IF_NOT_OK(io_block_queues_[(buf_cnt_++) % num_workers_]->Add(std::move(eof_block)));
+      RETURN_IF_NOT_OK(io_block_queues_[(row_cnt++) % num_workers_]->Add(std::move(eoe_block)));
+      RETURN_IF_NOT_OK(io_block_queues_[(row_cnt++) % num_workers_]->Add(std::move(eof_block)));
       for (int32_t i = 0; i < num_workers_; ++i) {
         RETURN_IF_NOT_OK(
           io_block_queues_[i]->Add(std::make_unique<IOBlock>(std::vector<int64_t>(), IOBlock::kDeIoBlockNone)));
@@ -73,7 +61,7 @@ Status MappableLeafOp::operator()() {
       return Status::OK();
     } else {  // not the last repeat.
       RETURN_IF_NOT_OK(
-        io_block_queues_[(buf_cnt_++) % num_workers_]->Add(std::make_unique<IOBlock>(IOBlock::kDeIoBlockFlagEoe)));
+        io_block_queues_[(row_cnt++) % num_workers_]->Add(std::make_unique<IOBlock>(IOBlock::kDeIoBlockFlagEoe)));
     }
 
     if (epoch_sync_flag_) {
@@ -104,49 +92,34 @@ Status MappableLeafOp::InitSampler() {
 }
 
 // contains the main logic of pulling a IOBlock from IOBlockQueue, load a buffer and push the buffer to out_connector_
-// IMPORTANT: 1 IOBlock produces 1 DataBuffer
+// IMPORTANT: 1 IOBlock produces 1 row
 Status MappableLeafOp::WorkerEntry(int32_t worker_id) {
   TaskManager::FindMe()->Post();
-  int64_t buffer_id = worker_id;
   std::unique_ptr<IOBlock> io_block;
   RETURN_IF_NOT_OK(io_block_queues_[worker_id]->PopFront(&io_block));
   while (io_block != nullptr) {
-    if (io_block->wait() == true) {
+    if (io_block->wait()) {
       // Sync io_block is a signal that master thread wants us to pause and sync with other workers.
       // The last guy who comes to this sync point should reset the counter and wake up the master thread.
       if (++num_workers_paused_ == num_workers_) {
         wait_for_workers_post_.Set();
       }
-    } else if (io_block->eoe() == true) {
-      RETURN_IF_NOT_OK(out_connector_->Add(worker_id, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE)));
-      buffer_id = worker_id;
-    } else if (io_block->eof() == true) {
-      RETURN_IF_NOT_OK(out_connector_->Add(worker_id, std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF)));
+    } else if (io_block->eoe()) {
+      RETURN_IF_NOT_OK(out_connector_->SendEOE(worker_id));
+    } else if (io_block->eof()) {
+      RETURN_IF_NOT_OK(out_connector_->SendEOF(worker_id));
     } else {
       std::vector<int64_t> keys;
       RETURN_IF_NOT_OK(io_block->GetKeys(&keys));
-      if (keys.empty() == true) return Status::OK();  // empty key is a quit signal for workers
-      std::unique_ptr<DataBuffer> db = std::make_unique<DataBuffer>(buffer_id, DataBuffer::kDeBFlagNone);
-      RETURN_IF_NOT_OK(LoadBuffer(keys, &db));
-      RETURN_IF_NOT_OK(out_connector_->Add(worker_id, std::move(db)));
-      buffer_id += num_workers_;
+      if (keys.empty()) return Status::OK();  // empty key is a quit signal for workers
+      TensorRow trow;
+      RETURN_IF_NOT_OK(this->LoadTensorRow(keys[0], &trow));
+      RETURN_IF_NOT_OK(out_connector_->Add(std::move(trow), worker_id));
     }
     RETURN_IF_NOT_OK(io_block_queues_[worker_id]->PopFront(&io_block));
   }
   RETURN_STATUS_UNEXPECTED("Unexpected nullptr received in worker");
 }
 
-// Looping over LoadTensorRow to make 1 DataBuffer. 1 function call produces 1 buffer
-Status MappableLeafOp::LoadBuffer(const std::vector<int64_t> &keys, std::unique_ptr<DataBuffer> *db) {
-  std::unique_ptr<TensorQTable> deq = std::make_unique<TensorQTable>();
-  TensorRow trow;
-  for (const int64_t &key : keys) {
-    RETURN_IF_NOT_OK(this->LoadTensorRow(key, &trow));
-    deq->push_back(std::move(trow));
-  }
-  (*db)->set_tensor_table(std::move(deq));
-  return Status::OK();
-}
-
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/mappable_leaf_op.h

@@ -52,53 +52,47 @@ using FolderImagesPair = std::shared_ptr<std::pair<std::string, std::queue<Image
 
 class MappableLeafOp : public ParallelOp, public RandomAccessOp {
  public:
-  // Constructor
-  // @param int32_t num_wkrs - Num of workers reading images in parallel
-  // @param int32_t - rows_per_buffer Number of images (rows) in each buffer
-  // @param std::string - dir directory of ImageNetFolder
-  // @param int32_t queue_size - connector queue size
-  // @param std::set<std::string> exts - set of file extensions to read, if empty, read everything under the dir
-  // @param td::unique_ptr<Sampler> sampler - sampler tells the source what to read
+  /// Constructor
+  /// \param int32_t num_wkrs - Num of workers reading images in parallel
+  /// \param int32_t queue_size - connector queue size
+  /// \param td::unique_ptr<Sampler> sampler - sampler tells the source  what to read
   MappableLeafOp(int32_t num_wkrs, int32_t queue_size, std::shared_ptr<SamplerRT> sampler, int32_t rows_per_buffer);
 
-  // Destructor.
+  /// Destructor.
   ~MappableLeafOp() = default;
 
-  // Main Loop of MappableLeaf
-  // Master thread: Fill IOBlockQueue, then goes to sleep
-  // Worker thread: pulls IOBlock from IOBlockQueue, work on it then put buffer to mOutConnector
-  // @return Status The status code returned
+  /// Main Loop of MappableLeaf
+  /// Master thread: Fill IOBlockQueue, then goes to sleep
+  /// Worker thread: pulls IOBlock from IOBlockQueue, work on it then put row to out_connector_
+  /// \return Status The status code returned
   Status operator()() override;
 
-  // Op name getter
-  // @return Name of the current Op
+  /// Op name getter
+  /// @return Name of the current Op
   std::string Name() const override { return "MappableLeafPp"; }
 
  protected:
-  // Initialize Sampler, calls sampler->Init() within
-  // @return Status The status code returned
+  /// Initialize Sampler, calls sampler->Init() within
+  /// @return Status The status code returned
   Status InitSampler();
 
-  //  // Called first when function is called
-  //  // @return
+  /// Called first when function is called
+  /// \return Status The status code returned
   virtual Status LaunchThreadsAndInitOp() = 0;
 
+  /// Worker thread pulls a number of IOBlock from IOBlock Queue, make a row and push it to Connector
+  /// \param int32_t workerId - id of each worker
+  /// \return Status The status code returned
   Status WorkerEntry(int32_t workerId) override;
 
-  // @param const std::vector<int64_t> &keys - keys in ioblock
-  // @param std::unique_ptr<DataBuffer> db
-  // @return Status The status code returned
-  Status LoadBuffer(const std::vector<int64_t> &keys, std::unique_ptr<DataBuffer> *db);
-
-  // Load a tensor row according to a pair
-  // @param row_id_type row_id - id for this tensor row
-  // @param ImageLabelPair pair - <imagefile,label>
-  // @param TensorRow row - loaded row
-  // @return Status The status code returned
+  /// Virtual function to Load a tensor row at location row_id
+  /// \param row_id_type row_id - id for this tensor row
+  /// \param TensorRow row - loaded row
+  /// \return Status The status code returned
   virtual Status LoadTensorRow(row_id_type row_id, TensorRow *row) = 0;
 
-  // reset Op
-  // @return Status The status code returned
+  /// Reset function to be called after every epoch to reset the source op after
+  /// \return Status The status code returned
   Status Reset() override;
 
   int32_t rows_per_buffer_;

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/mindrecord_op.cc

@@ -70,10 +70,9 @@ Status MindRecordOp::Builder::Build(std::shared_ptr<MindRecordOp> *ptr) {
   if (build_num_padded_ > 0) {
     sample_json = ToJson(build_sample_);
   }
-  new_mind_record_op =
-    std::make_shared<MindRecordOp>(build_num_mind_record_workers_, build_rows_per_buffer_, build_dataset_file_,
-                                   build_load_dataset_, build_op_connector_queue_size_, build_columns_to_load_,
-                                   build_operators_, build_num_padded_, sample_json, build_sample_bytes_);
+  new_mind_record_op = std::make_shared<MindRecordOp>(
+    build_num_mind_record_workers_, build_dataset_file_, build_load_dataset_, build_op_connector_queue_size_,
+    build_columns_to_load_, build_operators_, build_num_padded_, sample_json, build_sample_bytes_);
 
   RETURN_IF_NOT_OK(new_mind_record_op->Init());
   *ptr = std::move(new_mind_record_op);
@@ -111,13 +110,11 @@ mindrecord::json MindRecordOp::Builder::ToJson(const py::handle &obj) {
 }
 
 // Constructor of the MindRecordOp.
-MindRecordOp::MindRecordOp(int32_t num_mind_record_workers, int32_t rows_per_buffer,
-                           std::vector<std::string> dataset_file, bool load_dataset, int32_t op_connector_queue_size,
-                           const std::vector<std::string> &columns_to_load,
+MindRecordOp::MindRecordOp(int32_t num_mind_record_workers, std::vector<std::string> dataset_file, bool load_dataset,
+                           int32_t op_connector_queue_size, const std::vector<std::string> &columns_to_load,
                            const std::vector<std::shared_ptr<ShardOperator>> &operators, int64_t num_padded,
                            const mindrecord::json &sample_json, const std::map<std::string, std::string> &sample_bytes)
-    : MappableLeafOp(num_mind_record_workers, op_connector_queue_size, std::make_shared<SequentialSamplerRT>(0, 0),
-                     rows_per_buffer),
+    : MappableLeafOp(num_mind_record_workers, op_connector_queue_size, std::make_shared<SequentialSamplerRT>(0, 0), 1),
       dataset_file_(dataset_file),
       load_dataset_(load_dataset),
       columns_to_load_(columns_to_load),
@@ -211,8 +208,7 @@ void MindRecordOp::Print(std::ostream &out, bool show_all) const {
     for (auto &file : dataset_file_) {
       out << file << " ";
     }
-    out << "\nNumber of rows : " << num_rows_ << "\nRows per buffer : " << rows_per_buffer_
-        << "\nNumber of buffers : " << buffers_needed_
+    out << "\nNumber of rows : " << num_rows_ << "\nNumber of buffers : " << buffers_needed_
         << "\nNumber of ShardReader workers : " << num_mind_record_workers_ << "\n\n";
   }
 }
@@ -232,14 +228,12 @@ Status MindRecordOp::WorkerEntry(int32_t worker_id) {
       continue;
     }
     if (io_block->eoe()) {
-      RETURN_IF_NOT_OK(
-        out_connector_->Add(worker_id, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE))));
+      RETURN_IF_NOT_OK(out_connector_->SendEOE(worker_id));
       RETURN_IF_NOT_OK(io_block_queues_[worker_id]->PopFront(&io_block));
       continue;
     }
     if (io_block->eof()) {
-      RETURN_IF_NOT_OK(
-        out_connector_->Add(worker_id, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF))));
+      RETURN_IF_NOT_OK(out_connector_->SendEOF(worker_id));
       RETURN_IF_NOT_OK(io_block_queues_[worker_id]->PopFront(&io_block));
       continue;
     }
@@ -256,52 +250,41 @@ Status MindRecordOp::WorkerEntry(int32_t worker_id) {
       return Status::OK();  // empty key is a quit signal for workers
     }
 
-    const uint64_t buffer_id = keys[0];
-    std::unique_ptr<DataBuffer> fetched_buffer;
+    const uint64_t row_id = keys[0];
+    TensorRow fetched_row;
 
     // Get the next buffer. Push it up to the output connector.
-    if (buffer_id % LOG_INTERVAL == 0) {
-      MS_LOG(DEBUG) << "MindRecord operator consumed buffer " << buffer_id << " by worker " << worker_id << ".";
+    if (row_id % LOG_INTERVAL == 0) {
+      MS_LOG(DEBUG) << "MindRecord operator consumed row " << row_id << " by worker " << worker_id << ".";
     }
-    RETURN_IF_NOT_OK(GetBufferFromReader(&fetched_buffer, buffer_id, worker_id));
-    RETURN_IF_NOT_OK(out_connector_->Add(worker_id, std::move(fetched_buffer)));
+    RETURN_IF_NOT_OK(GetRowFromReader(&fetched_row, row_id, worker_id));
+    RETURN_IF_NOT_OK(out_connector_->Add(std::move(fetched_row), worker_id));
     RETURN_IF_NOT_OK(io_block_queues_[worker_id]->PopFront(&io_block));
   }
   RETURN_STATUS_UNEXPECTED("Unexpected nullptr received in worker.");
 }
 
-Status MindRecordOp::GetBufferFromReader(std::unique_ptr<DataBuffer> *fetched_buffer, int64_t buffer_id,
-                                         int32_t worker_id) {
-  *fetched_buffer = std::make_unique<DataBuffer>(buffer_id, DataBuffer::kDeBFlagNone);
-  std::unique_ptr<TensorQTable> tensor_table = std::make_unique<TensorQTable>();
-  for (int32_t i = 0; i < rows_per_buffer_; ++i) {
-    int32_t row_id = buffer_id * rows_per_buffer_ + i;
-    auto rc = shard_reader_->GetNextById(row_id, worker_id);
-    auto task_type = rc.first;
-    auto tupled_buffer = rc.second;
-    if (task_type == mindrecord::TaskType::kPaddedTask) {
-      TensorRow tensor_row;
-      RETURN_IF_NOT_OK(LoadTensorRow(&tensor_row, {}, mindrecord::json(), task_type));
-      std::vector<std::string> file_path(tensor_row.size(), dataset_file_[0]);
-      tensor_row.setPath(file_path);
-      tensor_table->push_back(std::move(tensor_row));
-    }
-    if (tupled_buffer.empty()) break;
-    if (task_type == mindrecord::TaskType::kCommonTask) {
-      for (const auto &tupled_row : tupled_buffer) {
-        std::vector<uint8_t> columns_blob = std::get<0>(tupled_row);
-        mindrecord::json columns_json = std::get<1>(tupled_row);
-        TensorRow tensor_row;
-        RETURN_IF_NOT_OK(LoadTensorRow(&tensor_row, columns_blob, columns_json, task_type));
-        std::vector<std::string> file_path(tensor_row.size(), dataset_file_[0]);
-        tensor_row.setPath(file_path);
-        tensor_table->push_back(std::move(tensor_row));
-      }
+Status MindRecordOp::GetRowFromReader(TensorRow *fetched_row, int64_t row_id, int32_t worker_id) {
+  *fetched_row = {};
+  auto rc = shard_reader_->GetNextById(row_id, worker_id);
+  auto task_type = rc.first;
+  auto tupled_buffer = rc.second;
+  if (task_type == mindrecord::TaskType::kPaddedTask) {
+    RETURN_IF_NOT_OK(LoadTensorRow(fetched_row, {}, mindrecord::json(), task_type));
+    std::vector<std::string> file_path(fetched_row->size(), dataset_file_[0]);
+    fetched_row->setPath(file_path);
+  }
+  if (tupled_buffer.empty()) return Status::OK();
+  if (task_type == mindrecord::TaskType::kCommonTask) {
+    for (const auto &tupled_row : tupled_buffer) {
+      std::vector<uint8_t> columns_blob = std::get<0>(tupled_row);
+      mindrecord::json columns_json = std::get<1>(tupled_row);
+      RETURN_IF_NOT_OK(LoadTensorRow(fetched_row, columns_blob, columns_json, task_type));
+      std::vector<std::string> file_path(fetched_row->size(), dataset_file_[0]);
+      fetched_row->setPath(file_path);
     }
   }
 
-  // Replace the TensorTable in DataBuffer with the new one.
-  (*fetched_buffer)->set_tensor_table(std::move(tensor_table));
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/mindrecord_op.h

@@ -134,13 +134,12 @@ class MindRecordOp : public MappableLeafOp {
   // Constructor of the MindRecordOp.
   // @note The builder class should be used to call it
   // @param num_mind_record_workers - The number of workers for the op (run by ShardReader)
-  // @param rows_per_buffer - The requested number of rows per buffer
   // @param dataset_file - dataset files
   // @param op_connector_queue_size - The output connector queue size
   // @param columns_to_load - The list of columns to use (column name)
   // @param operators - ShardOperators for Shuffle, Category, Sample
-  MindRecordOp(int32_t num_mind_record_workers, int32_t rows_per_buffer, std::vector<std::string> dataset_file,
-               bool load_dataset, int32_t op_connector_queue_size, const std::vector<std::string> &columns_to_load,
+  MindRecordOp(int32_t num_mind_record_workers, std::vector<std::string> dataset_file, bool load_dataset,
+               int32_t op_connector_queue_size, const std::vector<std::string> &columns_to_load,
                const std::vector<std::shared_ptr<ShardOperator>> &operators, int64_t num_padded_,
                const mindrecord::json &sample_json, const std::map<std::string, std::string> &sample_bytes_);
 
@@ -195,7 +194,7 @@ class MindRecordOp : public MappableLeafOp {
   std::string Name() const override { return "MindRecordOp"; }
 
  private:
-  Status GetBufferFromReader(std::unique_ptr<DataBuffer> *fetched_buffer, int64_t buffer_id, int32_t worker_id);
+  Status GetRowFromReader(TensorRow *fetched_row, int64_t row_id, int32_t worker_id);
 
   // Parses a single cell and puts the data into a tensor
   // @param tensor_row - the tensor row to put the parsed data in

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/nonmappable_leaf_op.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2019-2021 Huawei Technologies Co., Ltd
+ * Copyright 2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -77,7 +77,6 @@ Status NonMappableLeafOp::operator()() {
 
   NotifyToFillIOBlockQueue();
   while (!finished_reading_dataset_) {
-    int64_t buffer_id = 0;
     int32_t workers_done = 0;
     int64_t rows_read = 0;
     {
@@ -86,22 +85,14 @@ Status NonMappableLeafOp::operator()() {
     }
 
     while (workers_done < num_workers_) {
-      std::unique_ptr<DataBuffer> fetched_buffer;
-      RETURN_IF_NOT_OK(jagged_buffer_connector_->Pop(0, &fetched_buffer));
-      if (fetched_buffer->eoe()) {
+      TensorRow fetched_row;
+      RETURN_IF_NOT_OK(jagged_buffer_connector_->Pop(0, &fetched_row));
+      if (fetched_row.eoe()) {
         workers_done++;
       } else if (total_rows_ == 0 || rows_read < total_rows_) {
-        // we need to push a buffer
-        if (total_rows_ > 0 && rows_read + fetched_buffer->NumRows() > total_rows_) {
-          // this is last buffer we need, and we only need a part of it
-          int64_t rowsToRemove = fetched_buffer->NumRows() - (total_rows_ - rows_read);
-          RETURN_IF_NOT_OK(fetched_buffer->SliceOff(rowsToRemove));
-        }
-
-        rows_read += fetched_buffer->NumRows();
-        fetched_buffer->set_id(buffer_id);
-        buffer_id++;
-        RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(fetched_buffer)));
+        // we need to push a row
+        RETURN_IF_NOT_OK(out_connector_->Add(std::move(fetched_row), 0));
+        rows_read++;
       } else {
         // IOBlockQueue thread needs to:
         // -stop pushing stuff to IOBlockQueue
@@ -126,23 +117,20 @@ Status NonMappableLeafOp::operator()() {
     }
 
     // all workers finished reading for this epoch, and we have read all the data from all workers
-    std::unique_ptr<DataBuffer> eoe_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE);
-    RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(eoe_buffer)));
+    RETURN_IF_NOT_OK(out_connector_->SendEOE());
 
     if (IsLastIteration()) {
       finished_reading_dataset_ = true;
       NotifyToFillIOBlockQueue();
     } else {
       jagged_buffer_connector_->DoReset();
-      buffer_id = 0;
       // Self-reset to start a new iteration
       RETURN_IF_NOT_OK(Reset());
     }
     UpdateRepeatAndEpochCounter();
   }
 
-  std::unique_ptr<DataBuffer> eof_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF);
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(eof_buffer)));
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
 
   RETURN_IF_NOT_OK(PostEndOfData());
 
@@ -168,8 +156,8 @@ Status NonMappableLeafOp::WorkerEntry(int32_t worker_id) {
         MS_LOG(DEBUG) << Name() << " operator worker " << worker_id << " loaded file " << filename << ".";
       }
     } else {
-      std::unique_ptr<DataBuffer> eoe_buffer = std::make_unique<DataBuffer>(1, DataBuffer::kDeBFlagEOE);
-      RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(eoe_buffer)));
+      TensorRow eoe = TensorRow(TensorRow::kFlagEOE);
+      RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(eoe)));
     }
 
     RETURN_IF_NOT_OK(PopIoBlockQueue(worker_id, &io_block));

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/nonmappable_leaf_op.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2019-2021 Huawei Technologies Co., Ltd
+ * Copyright 2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,12 +30,6 @@
 #include "minddata/dataset/core/tensor.h"
 #include "minddata/dataset/engine/datasetops/parallel_op.h"
 
-namespace dataengine {
-class Example;
-class Feature;
-class BytesList;
-}  // namespace dataengine
-
 namespace mindspore {
 namespace dataset {
 template <typename T>

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/random_data_op.cc

@@ -46,8 +46,8 @@ RandomDataOp::Builder::Builder()
 Status RandomDataOp::Builder::Build(std::shared_ptr<RandomDataOp> *out_op) {
   RETURN_IF_NOT_OK(SanityCheck());
 
-  *out_op = std::make_shared<RandomDataOp>(builder_num_workers_, builder_op_connector_size_, builder_rows_per_buffer_,
-                                           builder_total_rows_, std::move(builder_data_schema_));
+  *out_op = std::make_shared<RandomDataOp>(builder_num_workers_, builder_op_connector_size_, builder_total_rows_,
+                                           std::move(builder_data_schema_));
 
   return Status::OK();
 }
@@ -61,13 +61,11 @@ Status RandomDataOp::Builder::SanityCheck() const {
 }
 
 // Constructor for RandomDataOp
-RandomDataOp::RandomDataOp(int32_t num_workers, int32_t op_connector_size, int64_t rows_per_buffer, int64_t total_rows,
+RandomDataOp::RandomDataOp(int32_t num_workers, int32_t op_connector_size, int64_t total_rows,
                            std::unique_ptr<DataSchema> data_schema)
     : ParallelOp(num_workers, op_connector_size),
-      buffer_id_(0),
-      rows_per_buffer_(rows_per_buffer),
       total_rows_(total_rows),
-      epoch_buffers_sent_(0),
+      epoch_rows_sent_(0),
       guys_in_(0),
       guys_out_(num_workers_),
       eoe_worker_id_(0),
@@ -97,8 +95,7 @@ void RandomDataOp::Print(std::ostream &out, bool show_all) const {
     // Call the super class for displaying any common detailed info
     ParallelOp::Print(out, show_all);
     // Then show any custom derived-internal stuff
-    out << "\nTotal_rows: " << total_rows_ << "\nRows per buffer: " << rows_per_buffer_ << "\nSchema:\n"
-        << *data_schema_ << "\n\n";
+    out << "\nTotal_rows: " << total_rows_ << " \nSchema:\n" << *data_schema_ << "\n\n";
   }
 }
 
@@ -147,18 +144,11 @@ Status RandomDataOp::operator()() {
                                "RandomDataOp expects total_rows < num_workers. total_row=" +
                                  std::to_string(total_rows_) + ", num_workers=" + std::to_string(num_workers_) + " .");
 
-  // First, compute how many buffers we'll need to satisfy the total row count.
-  // The only reason we do this is for the purpose of throttling worker count if needed.
-  int64_t buffers_needed = total_rows_ / rows_per_buffer_;
-  if (total_rows_ % rows_per_buffer_ != 0) {
-    buffers_needed++;
-  }
-
-  // If the amount of workers we have exceeds the number of buffers to produce, then we'll have
+  // If the amount of workers we have exceeds the number of rows to produce, then we'll have
   // idle workers doing nothing.  In that case, let's throttle the worker count.
-  if (num_workers_ > buffers_needed) {
-    MS_LOG(INFO) << "RandomDataOp throttling worker count from " << num_workers_ << "to " << buffers_needed;
-    num_workers_ = buffers_needed;
+  if (num_workers_ > total_rows_) {
+    MS_LOG(INFO) << "RandomDataOp throttling worker count from " << num_workers_ << "to " << total_rows_;
+    num_workers_ = total_rows_;
     num_producers_ = num_workers_;
     guys_out_ = num_workers_;
     // The output connector was already created with a different worker count.  We have to drop and recreate
@@ -181,18 +171,15 @@ Status RandomDataOp::operator()() {
     currentWorker = (currentWorker + 1) % num_workers_;
   }
 
-  // Next, compute the total buffer count.  This stat is needed during reset logic
+  // Next, compute the total rows count.  This stat is needed during reset logic
   for (int32_t w = 0; w < num_workers_; w++) {
-    int64_t worker_buffers = 0;
-    worker_buffers = worker_max_rows_[w] / rows_per_buffer_;
-    if (worker_max_rows_[w] % rows_per_buffer_ != 0) worker_buffers++;
-    epoch_buffers_sent_ += worker_buffers;
+    epoch_rows_sent_ += worker_max_rows_[w];
   }
 
   // For the connector to work, we need to target the correct worker channel for the eoe.
   // This will initialize it for the first one.  reset() handles for the rest of the epochs.
-  eoe_worker_id_ = epoch_buffers_sent_ % num_workers_;
-  epoch_buffers_sent_++;  // Add the eoe buffer to the count for subsequent epochs
+  eoe_worker_id_ = epoch_rows_sent_ % num_workers_;
+  epoch_rows_sent_++;  // Add the eoe row to the count for subsequent epochs
 
   // RandomDataOp doesn't need the master thread to stay around.  Kick off the workers and then master exits.
   RETURN_IF_NOT_OK(
@@ -228,16 +215,14 @@ Status RandomDataOp::EpochSync(int32_t worker_id, bool *quitting) {
     // Prepare for sync
     all_out_.Clear();
     // Always flow eoe at the end
-    std::unique_ptr<DataBuffer> eoe_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE);
-    RETURN_IF_NOT_OK(out_connector_->Add(eoe_worker_id_, std::move(eoe_buffer)));
+    RETURN_IF_NOT_OK(out_connector_->SendEOE(eoe_worker_id_));
     // If we're done then also flow the eof
     if (*quitting) {
       // The eof needs to be sent from the next sender in the round robin, so +1
       int32_t eof_worker_id = (eoe_worker_id_ + 1) % num_workers_;
       MS_LOG(INFO) << "RandomDataOp worker " << worker_id << " has no more epochs.  sending eof as worker "
                    << eof_worker_id;
-      std::unique_ptr<DataBuffer> eof_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF);
-      RETURN_IF_NOT_OK(out_connector_->Add(eof_worker_id, std::move(eof_buffer)));
+      RETURN_IF_NOT_OK(out_connector_->SendEOF(eof_worker_id));
     }
   }
 
@@ -290,21 +275,12 @@ Status RandomDataOp::WorkerEntry(int32_t worker_id) {
       RETURN_IF_NOT_OK(CreateRandomRow(worker_id, &new_row));
 
       // Add the row to our table
-      new_tensor_table->push_back(std::move(new_row));
       worker_rows_packed_[worker_id]++;
 
-      // If the tensor table is at capacity then it's time to send it to output
-      if (new_tensor_table->size() == rows_per_buffer_) {
-        RETURN_IF_NOT_OK(PackAndSend(worker_id, std::move(new_tensor_table)));
-      }
-    } else {
-      // We've reached the total row count for this worker, so it's time for epoch sync.
-      // There is likely some records built but not sent yet, so take care of those first
-      // (this buffer will be smaller than rows_per_buffer)
-      if (new_tensor_table != nullptr && new_tensor_table->size() > 0) {
-        RETURN_IF_NOT_OK(PackAndSend(worker_id, std::move(new_tensor_table)));
-      }
+      // Send new_row out
+      RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row), worker_id));
 
+    } else {
       // Now, let's enter the epoch sync
       RETURN_IF_NOT_OK(EpochSync(worker_id, &quitting));
     }
@@ -315,14 +291,6 @@ Status RandomDataOp::WorkerEntry(int32_t worker_id) {
   return Status::OK();
 }
 
-// A helper function to stuff the tensor table into a buffer and send it to output connector
-Status RandomDataOp::PackAndSend(int32_t worker_id, std::unique_ptr<TensorQTable> in_table) {
-  auto new_buffer = std::make_unique<DataBuffer>(GetNextBufferId(), DataBuffer::kDeBFlagNone);
-  new_buffer->set_tensor_table(std::move(in_table));
-  RETURN_IF_NOT_OK(out_connector_->Add(worker_id, std::move(new_buffer)));
-  return Status::OK();
-}
-
 // A helper function to create random data for the row
 Status RandomDataOp::CreateRandomRow(int32_t worker_id, TensorRow *new_row) {
   if (new_row == nullptr) {
@@ -385,7 +353,6 @@ Status RandomDataOp::Reset() {
     worker_rows_packed_[w] = 0;
     worker_max_rows_[w] = 0;
   }
-  buffer_id_ = 0;
 
   // Re-assign round robin row counts, starting from the worker after the one that gave
   // the eoe last time
@@ -396,7 +363,7 @@ Status RandomDataOp::Reset() {
   }
 
   // Compute which worker should get the eoe for the next epoch
-  eoe_worker_id_ = ((epoch_buffers_sent_ % num_workers_) + eoe_worker_id_) % num_workers_;
+  eoe_worker_id_ = ((epoch_rows_sent_ % num_workers_) + eoe_worker_id_) % num_workers_;
 
   // Wake up the workers to get them going again in a new epoch
   guys_out_ = 0;

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/random_data_op.h

@@ -136,12 +136,11 @@ class RandomDataOp : public ParallelOp {
    * @note Private constructor.  Must use builder to construct.
    * @param num_workers - The number of workers
    * @param op_connector_size - The size of the output connector
-   * @param rows_per_buffer - The number of rows in each DataBuffer
    * @param data_schema - A user-provided schema
    * @param total_rows - The total number of rows in the dataset
    * @return Builder - The modified builder by reference
    */
-  RandomDataOp(int32_t num_workers, int32_t op_connector_size, int64_t rows_per_buffer, int64_t total_rows,
+  RandomDataOp(int32_t num_workers, int32_t op_connector_size, int64_t total_rows,
                std::unique_ptr<DataSchema> data_schema);
 
   /**
@@ -213,14 +212,6 @@ class RandomDataOp : public ParallelOp {
    */
   Status EpochSync(int32_t worker_id, bool *quitting);
 
-  /**
-   * A helper function to stuff the tensor table into a buffer and send it to output connector
-   * @param worker_id - The worker id
-   * @param in_table - The tensor table to pack and send
-   * @return Status The status code returned
-   */
-  Status PackAndSend(int32_t worker_id, std::unique_ptr<TensorQTable> in_table);
-
   /**
    * A helper function to create random data for the row
    * @param worker_id - The worker id
@@ -240,23 +231,12 @@ class RandomDataOp : public ParallelOp {
     return uniDist(rand_gen_);
   }
 
-  /**
-   * A quick inline for producing the next buffer id in sequence, threadsafe
-   * @return - The next buffer id.
-   */
-  inline int32_t GetNextBufferId() {
-    std::unique_lock<std::mutex> lock(buffer_id_mutex_);
-    return ++buffer_id_;
-  }
-
   // Private function for computing the assignment of the column name map.
   // @return - Status
   Status ComputeColMap() override;
 
-  int32_t buffer_id_;
-  int64_t rows_per_buffer_;
   int64_t total_rows_;
-  int64_t epoch_buffers_sent_;
+  int64_t epoch_rows_sent_;
   std::atomic<int32_t> guys_in_;
   std::atomic<int32_t> guys_out_;
   int32_t eoe_worker_id_;
@@ -266,7 +246,6 @@ class RandomDataOp : public ParallelOp {
   std::mt19937 rand_gen_;
   WaitPost epoch_sync_wait_post_;
   WaitPost all_out_;
-  std::mutex buffer_id_mutex_;
 };  // class RandomDataOp
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/text_file_op.cc

@@ -117,10 +117,10 @@ Status TextFileOp::Init() {
   return Status::OK();
 }
 
-Status TextFileOp::LoadTensor(const std::string &line, std::unique_ptr<TensorQTable> *tensor_table, int64_t row) {
+Status TextFileOp::LoadTensor(const std::string &line, TensorRow *out_row) {
   std::shared_ptr<Tensor> tensor;
   RETURN_IF_NOT_OK(Tensor::CreateScalar(line, &tensor));
-  (**tensor_table)[row][0] = std::move(tensor);
+  (*out_row)[0] = std::move(tensor);
   return Status::OK();
 }
 
@@ -130,11 +130,8 @@ Status TextFileOp::LoadFile(const std::string &file, int64_t start_offset, int64
     RETURN_STATUS_UNEXPECTED("Invalid file, failed to open file: " + file);
   }
 
-  int64_t rows_each_buffer = 0;
   int64_t rows_total = 0;
   std::string line;
-  std::unique_ptr<DataBuffer> cur_buffer = std::make_unique<DataBuffer>(0, DataBuffer::BufferFlags::kDeBFlagNone);
-  std::unique_ptr<TensorQTable> tensor_table = std::make_unique<TensorQTable>();
 
   while (getline(handle, line)) {
     if (line.empty()) {
@@ -152,23 +149,10 @@ Status TextFileOp::LoadFile(const std::string &file, int64_t start_offset, int64
 
     TensorRow tRow(1, nullptr);
     tRow.setPath({file});
-    tensor_table->push_back(std::move(tRow));
-    RETURN_IF_NOT_OK(LoadTensor(line, &tensor_table, rows_each_buffer));
-    rows_each_buffer++;
-    rows_total++;
-    if (rows_each_buffer == rows_per_buffer_) {
-      cur_buffer->set_tensor_table(std::move(tensor_table));
-      RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(cur_buffer)));
+    RETURN_IF_NOT_OK(LoadTensor(line, &tRow));
+    RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(tRow)));
 
-      cur_buffer = std::make_unique<DataBuffer>(0, DataBuffer::BufferFlags::kDeBFlagNone);
-      tensor_table = std::make_unique<TensorQTable>();
-      rows_each_buffer = 0;
-    }
-  }
-
-  if (rows_each_buffer > 0) {
-    cur_buffer->set_tensor_table(std::move(tensor_table));
-    RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(cur_buffer)));
+    rows_total++;
   }
 
   return Status::OK();

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/text_file_op.h

@@ -173,7 +173,7 @@ class TextFileOp : public NonMappableLeafOp {
   // @param tensor_table - the tensor table to put the parsed data in.
   // @param row - the id of the row filled in the tensor table.
   // @return Status - the error code returned.
-  Status LoadTensor(const std::string &line, std::unique_ptr<TensorQTable> *tensor_table, int64_t row);
+  Status LoadTensor(const std::string &line, TensorRow *out_row);
 
   // Reads a text file and loads the data into multiple buffers.
   // @param file - the file to read.

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/tf_reader_op.cc

@@ -316,8 +316,6 @@ Status TFReaderOp::LoadFile(const std::string &filename, int64_t start_offset, i
 
   int64_t rows_read = 0;
   int64_t rows_total = 0;
-  std::unique_ptr<DataBuffer> current_buffer = std::make_unique<DataBuffer>(0, DataBuffer::BufferFlags::kDeBFlagNone);
-  std::unique_ptr<TensorQTable> new_tensor_table = std::make_unique<TensorQTable>();
 
   while (reader.peek() != EOF) {
     if (!load_jagged_connector_) {
@@ -336,6 +334,10 @@ Status TFReaderOp::LoadFile(const std::string &filename, int64_t start_offset, i
     std::string serialized_example;
     serialized_example.resize(record_length);
     (void)reader.read(&serialized_example[0], static_cast<std::streamsize>(record_length));
+
+    int32_t num_columns = data_schema_->NumColumns();
+    TensorRow newRow(num_columns, nullptr);
+
     if (start_offset == kInvalidOffset || (rows_total >= start_offset && rows_total < end_offset)) {
       dataengine::Example tf_file;
       if (!tf_file.ParseFromString(serialized_example)) {
@@ -343,40 +345,24 @@ Status TFReaderOp::LoadFile(const std::string &filename, int64_t start_offset, i
         MS_LOG(DEBUG) << errMsg + ", details of string: " << serialized_example;
         RETURN_STATUS_UNEXPECTED(errMsg);
       }
-      int32_t num_columns = data_schema_->NumColumns();
-      TensorRow newRow(num_columns, nullptr);
+
       std::vector<std::string> file_path(num_columns, filename);
       newRow.setPath(file_path);
-      new_tensor_table->push_back(std::move(newRow));
-      RETURN_IF_NOT_OK(LoadExample(&tf_file, &new_tensor_table, rows_read));
+      RETURN_IF_NOT_OK(LoadExample(&tf_file, &newRow));
       rows_read++;
+      RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(newRow)));
     }
 
     // ignore crc footer
     (void)reader.ignore(static_cast<std::streamsize>(sizeof(int32_t)));
     rows_total++;
-
-    if (rows_read == rows_per_buffer_) {
-      current_buffer->set_tensor_table(std::move(new_tensor_table));
-      RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(current_buffer)));
-
-      current_buffer = std::make_unique<DataBuffer>(0, DataBuffer::BufferFlags::kDeBFlagNone);
-      new_tensor_table = std::make_unique<TensorQTable>();
-      rows_read = 0;
-    }
-  }
-
-  if (rows_read > 0) {
-    current_buffer->set_tensor_table(std::move(new_tensor_table));
-    RETURN_IF_NOT_OK(jagged_buffer_connector_->Add(worker_id, std::move(current_buffer)));
   }
 
   return Status::OK();
 }
 
 // Parses a single row and puts the data into a tensor table.
-Status TFReaderOp::LoadExample(const dataengine::Example *tf_file, std::unique_ptr<TensorQTable> *tensor_table,
-                               int64_t row) {
+Status TFReaderOp::LoadExample(const dataengine::Example *tf_file, TensorRow *out_row) {
   int32_t num_columns = data_schema_->NumColumns();
   for (int32_t col = 0; col < num_columns; ++col) {
     const ColDescriptor current_col = data_schema_->column(col);
@@ -387,16 +373,15 @@ Status TFReaderOp::LoadExample(const dataengine::Example *tf_file, std::unique_p
       RETURN_STATUS_UNEXPECTED("Invalid parameter, column name: " + current_col.name() + " does not exist.");
     }
     const dataengine::Feature &column_values_list = iter_column->second;
-    RETURN_IF_NOT_OK(LoadFeature(tensor_table, column_values_list, current_col, row, col));
+    RETURN_IF_NOT_OK(LoadFeature(out_row, column_values_list, current_col, col));
   }
 
   return Status::OK();
 }
 
 // Parses a single cell and puts the data into a tensor table.
-Status TFReaderOp::LoadFeature(const std::unique_ptr<TensorQTable> *tensor_table,
-                               const dataengine::Feature &column_values_list, const ColDescriptor &current_col,
-                               int64_t row, int32_t col) {
+Status TFReaderOp::LoadFeature(TensorRow *tensor_row, const dataengine::Feature &column_values_list,
+                               const ColDescriptor &current_col, int32_t col) {
   const dataengine::Feature::KindCase column_list_type = column_values_list.kind_case();
   std::unique_ptr<float[]> float_array;     // For staging data from protobuf deserialization
   const unsigned char *data_ptr = nullptr;  // Generic pointer used for populating the Tensor
@@ -444,7 +429,7 @@ Status TFReaderOp::LoadFeature(const std::unique_ptr<TensorQTable> *tensor_table
     }
   }
 
-  (**tensor_table)[row][col] = std::move(ts);
+  (*tensor_row)[col] = std::move(ts);
 
   return Status::OK();
 }

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/tf_reader_op.h

@@ -233,15 +233,15 @@ class TFReaderOp : public NonMappableLeafOp {
   // @param tensor_table - the tensor table to put the parsed data in.
   // @param row - the id of the row filled in the tensor table.
   // @return Status - the error code returned.
-  Status LoadExample(const dataengine::Example *tf_file, std::unique_ptr<TensorQTable> *tensor_table, int64_t row);
+  Status LoadExample(const dataengine::Example *tf_file, TensorRow *out_row);
 
   // Parses a single cell and puts the data into a tensor table.
   // @param tensor_table - the tensor table to put the parsed data in.
   // @param column_values_list - the cell to parse.
   // @param current_col - the column descriptor containing the expected shape and type of the data.
   // @return Status - the error code returned.
-  Status LoadFeature(const std::unique_ptr<TensorQTable> *tensor_table, const dataengine::Feature &column_values_list,
-                     const ColDescriptor &current_col, int64_t row, int32_t col);
+  Status LoadFeature(TensorRow *tensor_row, const dataengine::Feature &column_values_list,
+                     const ColDescriptor &current_col, int32_t col);
 
   // Reads values from a bytes list
   // @param current_col - the column descriptor containing the expected shape and type of the data.

mindspore/ccsrc/minddata/dataset/engine/datasetops/take_op.cc

@@ -20,6 +20,7 @@
 #include "utils/ms_utils.h"
 #include "minddata/dataset/core/config_manager.h"
 #include "minddata/dataset/engine/data_buffer.h"
+#include "minddata/dataset/engine/dataset_iterator.h"
 #include "minddata/dataset/engine/datasetops/take_op.h"
 #include "minddata/dataset/engine/db_connector.h"
 #include "minddata/dataset/engine/execution_tree.h"
@@ -69,60 +70,32 @@ void TakeOp::Print(std::ostream &out, bool show_all) const {
 // Main entry point for Take
 Status TakeOp::operator()() {
   TaskManager::FindMe()->Post();
-  std::unique_ptr<DataBuffer> buf;
-  RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buf));
+  child_iterator_ = std::make_unique<ChildIterator>(this, 0, 0);
 
-  while (buf->eof() == false) {
-    if (take_count_ == max_takes_) {
-      // Do drain Operation
-      while (!buf->eoe() && !buf->eof()) {
-        RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buf));
-      }
-    }
-
-    // Loop until non EOE is received
-    if (buf->eoe()) {
-      UpdateRepeatAndEpochCounter();
-      take_count_ = 0;
-      RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(buf)));
-      RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buf));
-      continue;
-    }
+  TensorRow new_row;
+  RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
 
-    // Get buffer and push back when take_count is still small
-    if (take_count_ < max_takes_) {
-      std::unique_ptr<DataBuffer> p_buffer;
-      RETURN_IF_NOT_OK(FillBuffer(&buf, &p_buffer));
-      RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(p_buffer)));
+  while (!new_row.eof()) {
+    while (!new_row.eoe()) {
+      if (take_count_ < max_takes_) {
+        RETURN_IF_NOT_OK(out_connector_->Add(std::move(new_row)));
+        take_count_++;
+        RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
+      }
+      if (take_count_ == max_takes_) {
+        RETURN_IF_NOT_OK(child_iterator_->Drain());
+        break;
+      }
     }
-    RETURN_IF_NOT_OK(child_[0]->GetNextBuffer(&buf));
+    UpdateRepeatAndEpochCounter();
+    take_count_ = 0;
+    RETURN_IF_NOT_OK(out_connector_->SendEOE());
+    RETURN_IF_NOT_OK(child_iterator_->FetchNextTensorRow(&new_row));
   }
 
   take_count_ = 0;
   MS_LOG(DEBUG) << "Meet the end and push-back eof buffer.";
-  auto eof_buffer = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF);
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(eof_buffer)));
-  return Status::OK();
-}
-
-// Function FillBuffer mainly prepare the buffer for returning
-Status TakeOp::FillBuffer(std::unique_ptr<DataBuffer> *buffer, std::unique_ptr<DataBuffer> *data_buffer) {
-  int32_t buffer_size = (*buffer)->NumRows();
-  if (take_count_ + buffer_size < max_takes_) {
-    *data_buffer = std::move(*buffer);
-    take_count_ = take_count_ + buffer_size;
-  } else {
-    MS_LOG(DEBUG) << "In last buffer: Push one buffer.";
-    std::unique_ptr<TensorQTable> new_tensor_table = std::make_unique<TensorQTable>();
-    while (take_count_ < max_takes_) {
-      TensorRow new_row;
-      RETURN_IF_NOT_OK((*buffer)->PopRow(&new_row));
-      take_count_++;
-      new_tensor_table->push_back(new_row);
-    }
-    (*buffer)->set_tensor_table(std::move(new_tensor_table));
-    *data_buffer = std::move(*buffer);
-  }
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/take_op.h

@@ -86,7 +86,7 @@ class TakeOp : public PipelineOp {
   int32_t max_takes_;   // The number of takes that the user requested
   int32_t take_count_;  // A counter for the current number of executed takes
 
-  Status FillBuffer(std::unique_ptr<DataBuffer> *buffer, std::unique_ptr<DataBuffer> *data_buffer);
+  std::unique_ptr<ChildIterator> child_iterator_;  // An iterator for fetching.
 };
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/engine/datasetops/zip_op.cc

@@ -72,96 +72,43 @@ Status ZipOp::operator()() {
 
   // Loop until eof is true
   while (!eof_) {
-    // Create tensor table and prepare it by fetching and packing the first zipped row into it.
-    std::unique_ptr<TensorQTable> curr_table = std::make_unique<TensorQTable>();
-    RETURN_IF_NOT_OK(prepare(curr_table.get()));
+    // 1 Prepare new epoch
+    RETURN_IF_NOT_OK(prepare());
+    // 2 fetch first row
+    TensorRow row;
+    RETURN_IF_NOT_OK(getNextTensorRow(&row));
 
-    // If an eof got picked up during the above prepare, then we're done
+    // If an eof got picked up, then we're done
     if (eof_) {
       break;
     }
     while (!draining_) {
-      // 1. If a previous loop iteration sent the current table out, then create a new one.
-      if (curr_table == nullptr) {
-        curr_table = std::make_unique<TensorQTable>();
-      }
-
-      // 2 fill the table.  Note: draining mode might get turned on if any of the child inputs were done
-      RETURN_IF_NOT_OK(fillBuffer(curr_table.get()));
-
-      // 3 create and update buffer and send it to the out connector
-      if (!curr_table->empty()) {
-        std::unique_ptr<DataBuffer> curr_buffer = std::make_unique<DataBuffer>(buffer_id_, DataBuffer::kDeBFlagNone);
-        curr_buffer->set_tensor_table(std::move(curr_table));
-        MS_LOG(DEBUG) << "Zip operator finished one buffer, pushing, rows " << curr_buffer->NumRows() << ", cols "
-                      << curr_buffer->NumCols() << ", map " << column_name_id_map_.size() << ".";
-        RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(curr_buffer)));
-        buffer_id_++;
-      }
+      // 3 send new row to the out connector
+      MS_LOG(DEBUG) << "Zip operator finished one row, pushing, cols " << row.size() << ", map "
+                    << column_name_id_map_.size() << ".";
+      RETURN_IF_NOT_OK(out_connector_->Add(std::move(row)));
+      // 4 fetch one more row
+      RETURN_IF_NOT_OK(getNextTensorRow(&row));
     }
-
-    // 4 handle drain state.
+    // 5 handle drain state.
     if (draining_) {
       MS_LOG(DEBUG) << "Zip operator is now draining child inputs.";
       RETURN_IF_NOT_OK(drainPipeline());
       // Now that we have drained child inputs, send the eoe up.
-      RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOE))));
+      RETURN_IF_NOT_OK(out_connector_->SendEOE());
     }
   }
 
-  // 5 handle eof
-  // propagate eof here.
+  // 6 handle eof
   MS_LOG(DEBUG) << "Zip operator got EOF, propagating.";
-  RETURN_IF_NOT_OK(out_connector_->Add(0, std::move(std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF))));
+  RETURN_IF_NOT_OK(out_connector_->SendEOF());
   return Status::OK();
 }
 
 // Handles preprocessing of the main loop, used when starting new epoch
-Status ZipOp::prepare(TensorQTable *const table) {
+Status ZipOp::prepare() {
   MS_LOG(DEBUG) << "Zip operator prepares for new epoch.";
   draining_ = false;
-  buffer_id_ = 0;
-  if (table == nullptr) {
-    return Status(StatusCode::kMDUnexpectedError, __LINE__, __FILE__,
-                  "Invalid data, ZipOp prepare phase requires a tensor table, but got nullptr.");
-  }
-  // fill initial row
-  TensorRow new_row;
-  RETURN_IF_NOT_OK(getNextTensorRow(&new_row));
-
-  // If the first row fetching resulted in eof, then we are done.
-  if (eof_) {
-    return Status::OK();
-  }
-  // One of our child iterators encounter EOE. Returns and proceed with draining phase.
-  if (new_row.empty()) {
-    return Status::OK();
-  }
-
-  // Pack this first row into our tensor table
-  table->push_back(std::move(new_row));
-
-  return Status::OK();
-}
-
-// fillBuffer always expects a new table to fill
-Status ZipOp::fillBuffer(TensorQTable *const table) {
-  if (table == nullptr) {
-    return Status(StatusCode::kMDUnexpectedError, __LINE__, __FILE__,
-                  "Invalid data, ZipOp fillBuffer null table pointer.");
-  }
-  TensorRow new_row;
-  while (table->size() < static_cast<size_t>(rows_per_buffer_)) {
-    RETURN_IF_NOT_OK(getNextTensorRow(&new_row));
-    // Early exit the loop if we got empty row from any of our child iterations
-    if (new_row.empty()) {
-      return Status::OK();
-    }
-    // else we got a row so pack it into the tensor table.
-    // Currently we don't support printing error info after zip
-    new_row.setPath({});
-    table->push_back(std::move(new_row));
-  }
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/zip_op.h

@@ -110,11 +110,7 @@ class ZipOp : public PipelineOp {
 
  private:
   // Handles preprocessing of the main loop, used when starting new epoch
-  Status prepare(TensorQTable *const table);
-
-  // This function calls takes a table repeatedly adds rows to it.
-  // @param table a table of tensors to be moved into a buffer
-  Status fillBuffer(TensorQTable *const table);
+  Status prepare();
 
   // Special handle case where an empty row has been received from child iterator
   // @note - we need to drain eoe signals from all children connectors.

mindspore/ccsrc/minddata/dataset/engine/db_connector.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2019 Huawei Technologies Co., Ltd
+ * Copyright 2019-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,7 +26,7 @@ namespace mindspore {
 namespace dataset {
 // DbConnector is a derived class from Connector with added logic to handle EOE and EOF.
 // The Connector class itself is responsible to ensure deterministic order on every run.
-class DbConnector : public Connector<std::unique_ptr<DataBuffer>> {
+class DbConnector : public Connector<TensorRow> {
  public:
   // Constructor of DbConnector
   // @note DbConnector will create internal N number of blocking queues, where N = nProducers.
@@ -35,7 +35,7 @@ class DbConnector : public Connector<std::unique_ptr<DataBuffer>> {
   // @param n_consumers The number of thread consuming data from this DbConnector.
   // @param queue_capacity The number of element (DataBuffer) for each internal queue.
   DbConnector(int32_t n_producers, int32_t n_consumers, int32_t queue_capacity)
-      : Connector<std::unique_ptr<DataBuffer>>(n_producers, n_consumers, queue_capacity), end_of_file_(false) {}
+      : Connector<TensorRow>(n_producers, n_consumers, queue_capacity), end_of_file_(false) {}
 
   // Destructor of DbConnector
   ~DbConnector() = default;
@@ -44,10 +44,19 @@ class DbConnector : public Connector<std::unique_ptr<DataBuffer>> {
   // @note The caller of this add method should use std::move to pass the ownership to DbConnector.
   // @param worker_id The id of a worker thread calling this method.
   // @param el A rvalue reference to an element to be passed/added/pushed.
-  Status Add(int32_t worker_id, std::unique_ptr<DataBuffer> &&el) noexcept {
-    return (Connector<std::unique_ptr<DataBuffer>>::Push(worker_id, std::move(el)));
+  Status Add(TensorRow &&el, int32_t worker_id = 0) noexcept {
+    return (Connector<TensorRow>::Push(worker_id, std::move(el)));
   }
 
+  Status SendEOE(int32_t worker_id = 0) noexcept {
+    TensorRow eoe = TensorRow(TensorRow::kFlagEOE);
+    return Add(std::move(eoe), worker_id);
+  }
+
+  Status SendEOF(int32_t worker_id = 0) noexcept {
+    TensorRow eof = TensorRow(TensorRow::kFlagEOF);
+    return Add(std::move(eof), worker_id);
+  }
   // Get a unique_ptr<DataBuffer> from the DbConnector.
   // @note After the first EOF Buffer is encountered, subsequent pop()s will return EOF Buffer.
   // This will provide/propagate the EOF to all consumer threads of this Connector.
@@ -56,7 +65,7 @@ class DbConnector : public Connector<std::unique_ptr<DataBuffer>> {
   // @param worker_id The id of a worker thread calling this method.
   // @param result The address of a unique_ptr<DataBuffer> where the popped element will be placed.
   // @param retry_if_eoe A flag to allow the same thread invoke pop() again if the current pop returns eoe buffer.
-  Status PopWithRetry(int32_t worker_id, std::unique_ptr<DataBuffer> *result, bool retry_if_eoe = false) noexcept {
+  Status PopWithRetry(int32_t worker_id, TensorRow *result, bool retry_if_eoe = false) noexcept {
     if (result == nullptr) {
       return Status(StatusCode::kMDUnexpectedError, __LINE__, __FILE__,
                     "[ERROR] nullptr detected when getting data from db connector");
@@ -65,21 +74,17 @@ class DbConnector : public Connector<std::unique_ptr<DataBuffer>> {
       RETURN_IF_NOT_OK(cv_.Wait(&lk, [this, worker_id]() { return (expect_consumer_ == worker_id) || end_of_file_; }));
       // Once an EOF message is encountered this flag will be set and we can return early.
       if (end_of_file_) {
-        *result = std::make_unique<DataBuffer>(0, DataBuffer::kDeBFlagEOF);
+        *result = TensorRow(TensorRow::kFlagEOF);
       } else {
         RETURN_IF_NOT_OK(queues_[pop_from_]->PopFront(result));
-        if (*result == nullptr) {
-          return Status(StatusCode::kMDUnexpectedError, __LINE__, __FILE__,
-                        "[ERROR] nullptr detected when getting data from db connector");
-        }
         // Setting the internal flag once the first EOF is encountered.
-        if ((*result)->eof()) {
+        if (result->eof()) {
           end_of_file_ = true;
         }
         pop_from_ = (pop_from_ + 1) % num_producers_;
       }
       // Do not increment expect_consumer_ when result is eoe and retry_if_eoe is set.
-      if (!((*result)->eoe() && retry_if_eoe)) {
+      if (!(result->eoe() && retry_if_eoe)) {
         expect_consumer_ = (expect_consumer_ + 1) % num_consumers_;
       }
     }

mindspore/ccsrc/minddata/dataset/engine/ir/datasetops/source/generator_node.cc

@@ -84,7 +84,7 @@ Status GeneratorNode::Build(std::vector<std::shared_ptr<DatasetOp>> *const node_
   // GeneratorOp's constructor takes in a prefetch_size, which isn't being set by user nor is it being used by
   // GeneratorOp internally. Here it is given a zero which is the default in generator builder
   std::shared_ptr<GeneratorOp> op = std::make_shared<GeneratorOp>(generator_function_, column_names_, column_types_, 0,
-                                                                  rows_per_buffer_, connector_que_size_, sampler_rt);
+                                                                  connector_que_size_, sampler_rt);
   // set the number of rows from source length
   op->SetNumRows(source_len_);
 

mindspore/ccsrc/minddata/dataset/engine/ir/datasetops/source/minddata_node.cc

@@ -159,13 +159,13 @@ Status MindDataNode::Build(std::vector<std::shared_ptr<DatasetOp>> *const node_o
   // else if pass a vector to MindData(), it will be treated as specified files to be read
   if (search_for_pattern_) {
     std::vector<std::string> dataset_file_vec_ = {dataset_file_};
-    mindrecord_op = std::make_shared<MindRecordOp>(num_workers_, rows_per_buffer_, dataset_file_vec_,
-                                                   search_for_pattern_, connector_que_size_, columns_list_, operators_,
-                                                   num_padded_, padded_sample_, sample_bytes_);
+    mindrecord_op =
+      std::make_shared<MindRecordOp>(num_workers_, dataset_file_vec_, search_for_pattern_, connector_que_size_,
+                                     columns_list_, operators_, num_padded_, padded_sample_, sample_bytes_);
   } else {
-    mindrecord_op = std::make_shared<MindRecordOp>(num_workers_, rows_per_buffer_, dataset_files_, search_for_pattern_,
-                                                   connector_que_size_, columns_list_, operators_, num_padded_,
-                                                   padded_sample_, sample_bytes_);
+    mindrecord_op =
+      std::make_shared<MindRecordOp>(num_workers_, dataset_files_, search_for_pattern_, connector_que_size_,
+                                     columns_list_, operators_, num_padded_, padded_sample_, sample_bytes_);
   }
 
   RETURN_IF_NOT_OK(mindrecord_op->Init());

mindspore/ccsrc/minddata/dataset/engine/ir/datasetops/source/random_node.cc

@@ -107,8 +107,7 @@ Status RandomNode::Build(std::vector<std::shared_ptr<DatasetOp>> *const node_ops
   }
 
   std::shared_ptr<RandomDataOp> op;
-  op = std::make_shared<RandomDataOp>(num_workers_, connector_que_size_, rows_per_buffer_, total_rows_,
-                                      std::move(data_schema_));
+  op = std::make_shared<RandomDataOp>(num_workers_, connector_que_size_, total_rows_, std::move(data_schema_));
   op->set_total_repeats(GetTotalRepeats());
   op->set_num_repeats_per_epoch(GetNumRepeatsPerEpoch());
   node_ops->push_back(op);

mindspore/ccsrc/minddata/dataset/engine/jagged_connector.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2019 Huawei Technologies Co., Ltd
+ * Copyright 2019-2021 Huawei Technologies Co., Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,10 +27,10 @@
 
 namespace mindspore {
 namespace dataset {
-class JaggedConnector : public Connector<std::unique_ptr<DataBuffer>> {
+class JaggedConnector : public Connector<TensorRow> {
  public:
   JaggedConnector(int32_t num_producers, int32_t num_consumers, int32_t queue_capacity)
-      : Connector<std::unique_ptr<DataBuffer>>(num_producers, num_consumers, queue_capacity) {
+      : Connector<TensorRow>(num_producers, num_consumers, queue_capacity) {
     for (int i = 0; i < num_producers; i++) {
       is_queue_finished_.push_back(false);
     }
@@ -38,11 +38,11 @@ class JaggedConnector : public Connector<std::unique_ptr<DataBuffer>> {
 
   ~JaggedConnector() = default;
 
-  Status Add(int32_t worker_d, std::unique_ptr<DataBuffer> &&element) noexcept {
-    return Connector<std::unique_ptr<DataBuffer>>::Push(worker_d, std::move(element));
+  Status Add(int32_t worker_d, TensorRow &&element) noexcept {
+    return Connector<TensorRow>::Push(worker_d, std::move(element));
   }
 
-  Status Pop(int32_t worker_id, std::unique_ptr<DataBuffer> *result) noexcept override {
+  Status Pop(int32_t worker_id, TensorRow *result) noexcept override {
     {
       MS_ASSERT(worker_id < num_consumers_);
       std::unique_lock<std::mutex> lock(m_);
@@ -53,7 +53,7 @@ class JaggedConnector : public Connector<std::unique_ptr<DataBuffer>> {
       }
 
       RETURN_IF_NOT_OK(queues_[pop_from_]->PopFront(result));
-      if ((*result)->eoe()) {
+      if (result->eoe()) {
         is_queue_finished_[pop_from_] = true;
       }
 
@@ -77,7 +77,7 @@ class JaggedConnector : public Connector<std::unique_ptr<DataBuffer>> {
       is_queue_finished_[i] = false;
     }
 
-    Connector<std::unique_ptr<DataBuffer>>::Reset();
+    Connector<TensorRow>::Reset();
   }
 
  private:

mindspore/ccsrc/minddata/dataset/engine/tree_adapter.cc

@@ -38,7 +38,7 @@
 namespace mindspore {
 namespace dataset {
 
-TreeAdapter::TreeAdapter(UsageFlag usage) : usage_(usage), tree_state_(kCompileStateInit) {
+TreeAdapter::TreeAdapter(UsageFlag usage) : usage_(usage), tree_state_(kCompileStateInit), launched_(false) {
   optimize_ = common::GetEnv("OPTIMIZE") == "true";
 
   // Initialize profiling parameters
@@ -215,44 +215,24 @@ Status TreeAdapter::GetNext(TensorRow *row) {
   bool isProfilingEnable = tree_->GetProfilingManager()->IsProfilingEnable();
 
   // When cur_db_ is a nullptr, it means this is the first call to get_next, launch ExecutionTree
-  if (cur_db_ == nullptr) {
-    RETURN_IF_NOT_OK(tree_->Launch());
-    // Profiling
-    std::shared_ptr<Tracing> node;
-    Status s = tree_->GetProfilingManager()->GetTracingNode(kDatasetIteratorTracingName, &node);
-    if (s.IsOk()) {
-      tracing_ = std::dynamic_pointer_cast<DatasetIteratorTracing>(node);
-      cur_connector_size_ = tree_->root()->ConnectorSize();
-      cur_connector_capacity_ = tree_->root()->ConnectorCapacity();
-    }
-    RETURN_IF_NOT_OK(tree_->root()->GetNextBuffer(&cur_db_));  // first buf can't be eof or empty buf with none flag
-    if (cur_db_->eoe()) {                                      // return empty tensor if 1st buf is a ctrl buf (no rows)
-      MS_LOG(INFO) << "End of data iteration.";
-      if (isProfilingEnable) {
-        tree_->SetEpochEnd();
-      }
-      return Status::OK();
-    }
+  if (!launched_) {
+    RETURN_IF_NOT_OK(Launch());
   }
 
-  CHECK_FAIL_RETURN_UNEXPECTED(!cur_db_->eof(), "EOF has already been reached.");
-
-  if (cur_db_->NumRows() == 0) {  // a new row is fetched if cur buf is empty or a ctrl buf
-    RETURN_IF_NOT_OK(tree_->root()->GetNextBuffer(&cur_db_));
-    if (cur_db_->eoe()) {  // return empty if this new buffer is a ctrl flag
-      MS_LOG(INFO) << "End of data iteration.";
-      if (isProfilingEnable) {
-        tree_->SetEpochEnd();
-      }
-      return Status::OK();
-    }
-    if (cur_db_->eof()) {
-      tree_->SetFinished();
-      std::string err = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs.";
-      RETURN_STATUS_UNEXPECTED(err);
+  RETURN_IF_NOT_OK(tree_->root()->GetNextRow(row));  // first buf can't be eof or empty buf with none flag
+  if (row->eoe()) {                                  // return empty tensor if 1st buf is a ctrl buf (no rows)
+    MS_LOG(INFO) << "End of data iteration.";
+    if (isProfilingEnable) {
+      tree_->SetEpochEnd();
     }
+    return Status::OK();
   }
-  RETURN_IF_NOT_OK(cur_db_->PopRow(row));
+  if (row->eof()) {
+    tree_->SetFinished();
+    std::string err = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs.";
+    RETURN_STATUS_UNEXPECTED(err);
+  }
+
   // Record profiling info
   if (tracing_ != nullptr) {
     uint64_t end_time = ProfilingTime::GetCurMilliSecond();
@@ -263,9 +243,19 @@ Status TreeAdapter::GetNext(TensorRow *row) {
   return Status::OK();
 }
 
-Status TreeAdapter::Launch() const {
+Status TreeAdapter::Launch() {
   CHECK_FAIL_RETURN_UNEXPECTED(tree_ != nullptr, "Tree is a nullptr.");
-  return tree_->Launch();
+  RETURN_IF_NOT_OK(tree_->Launch());
+  launched_ = true;
+  // Profiling
+  std::shared_ptr<Tracing> node;
+  Status s = tree_->GetProfilingManager()->GetTracingNode(kDatasetIteratorTracingName, &node);
+  if (s.IsOk()) {
+    tracing_ = std::dynamic_pointer_cast<DatasetIteratorTracing>(node);
+    cur_connector_size_ = tree_->root()->ConnectorSize();
+    cur_connector_capacity_ = tree_->root()->ConnectorCapacity();
+  }
+  return Status::OK();
 }
 
 }  // namespace dataset

mindspore/ccsrc/minddata/dataset/engine/tree_adapter.h

@@ -64,7 +64,7 @@ class TreeAdapter {
   // to be able to launch a thread. BuildAndPrepare needs to be called before this function
   TaskGroup *const AllTasks() const { return tree_ ? tree_->AllTasks() : nullptr; }
 
-  Status Launch() const;
+  Status Launch();
 
   // Set optional optimization pass
   void SetOptimize(bool value) { optimize_ = value; }
@@ -88,7 +88,6 @@ class TreeAdapter {
   // This RECURSIVE function walks the (optimized) IR tree in DFS to build its corresponding Execution tree.
   Status BuildExecutionTreeRecur(std::shared_ptr<DatasetNode> ir, std::shared_ptr<DatasetOp> *op);
 
-  std::unique_ptr<DataBuffer> cur_db_;
   std::unordered_map<std::string, int32_t> column_name_map_;
   std::shared_ptr<DatasetNode> root_ir_;
   std::unique_ptr<ExecutionTree> tree_;              // current connector capacity of root op, used for profiling
@@ -98,6 +97,7 @@ class TreeAdapter {
   int32_t cur_connector_size_;                       // current connector size of root op, used for profiling
   int32_t cur_connector_capacity_;                   // current connector capacity of root op, used for profiling
   UsageFlag usage_;                                  // usage of this tree adapter (type of consumer)
+  bool launched_;
   // State flags for the lifecycle of the tree
   enum CompileState {
     kCompileStateInit = 0,      // The freshly initialized state

mindspore/ccsrc/minddata/dataset/engine/tree_adapter_lite.cc

@@ -56,7 +56,7 @@ Status TreeAdapterLite::BuildTree(std::shared_ptr<DatasetNode> root_ir) {
 
 Status TreeAdapterLite::GetNextRow(TensorRow *row) {
   RETURN_UNEXPECTED_IF_NULL(root_);
-  RETURN_IF_NOT_OK(root_->GetNextRow(row));
+  RETURN_IF_NOT_OK(root_->GetNextRowPullMode(row));
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/include/iterator.h

@@ -31,7 +31,6 @@ namespace dataset {
 
 // Forward declare
 class ExecutionTree;
-class DatasetIterator;
 class DatasetOp;
 class Tensor;
 

tests/ut/cpp/dataset/cache_op_test.cc

@@ -277,7 +277,7 @@ TEST_F(MindDataTestCacheOp, DISABLED_TestRandomDataCache1) {
   rc = CacheOp::Builder()
          .SetNumWorkers(5)
          .SetClient(myClient)
-         .SetRowsPerBuffer(4)
+         .SetRowsPerBuffer(1)
          .SetSampler(std::move(seq_sampler))
          .Build(&myCacheOp);
   ASSERT_TRUE(rc.IsOk());

tests/ut/python/dataset/test_epoch_ctrl.py

@@ -1,4 +1,4 @@
-# Copyright 2020 Huawei Technologies Co., Ltd
+# Copyright 2020-2021 Huawei Technologies Co., Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -111,7 +111,7 @@ def test_decode_op():
 
     with pytest.raises(RuntimeError) as info:
         iter2.__next__()
-    err_msg = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs."
+    err_msg = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs."
     assert err_msg in str(info.value)
 
 
@@ -227,7 +227,7 @@ def test_generator_dict_4():
 
     with pytest.raises(RuntimeError) as info:
         iter1.__next__()
-    err_msg = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs."
+    err_msg = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs."
     assert err_msg in str(info.value)
 
 
@@ -251,7 +251,7 @@ def test_generator_dict_4_1():
 
     with pytest.raises(RuntimeError) as info:
         iter1.__next__()
-    err_msg = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs."
+    err_msg = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs."
     assert err_msg in str(info.value)
 
 
@@ -277,7 +277,7 @@ def test_generator_dict_4_2():
 
     with pytest.raises(RuntimeError) as info:
         iter1.__next__()
-    err_msg = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs."
+    err_msg = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs."
     assert err_msg in str(info.value)
 
 
@@ -309,7 +309,7 @@ def test_generator_dict_5():
     # now iter1 has been exhausted, c++ pipeline has been shut down.
     with pytest.raises(RuntimeError) as info:
         iter1.__next__()
-    err_msg = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs."
+    err_msg = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs."
     assert err_msg in str(info.value)
 
 
@@ -418,7 +418,7 @@ def test_generator_tuple_4():
 
     with pytest.raises(RuntimeError) as info:
         iter1.__next__()
-    err_msg = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs."
+    err_msg = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs."
     assert err_msg in str(info.value)
 
 
@@ -450,7 +450,7 @@ def test_generator_tuple_5():
     # now iter1 has been exhausted, c++ pipeline has been shut down.
     with pytest.raises(RuntimeError) as info:
         iter1.__next__()
-    err_msg = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs."
+    err_msg = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs."
     assert err_msg in str(info.value)
 
 
@@ -484,7 +484,7 @@ def test_generator_tuple_repeat_1():
     # now iter1 has been exhausted, c++ pipeline has been shut down.
     with pytest.raises(RuntimeError) as info:
         iter1.__next__()
-    err_msg = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs."
+    err_msg = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs."
     assert err_msg in str(info.value)
 
 
@@ -519,7 +519,7 @@ def test_generator_tuple_repeat_repeat_1():
     # now iter1 has been exhausted, c++ pipeline has been shut down.
     with pytest.raises(RuntimeError) as info:
         iter1.__next__()
-    err_msg = "EOF buffer encountered. Users try to fetch data beyond the specified number of epochs."
+    err_msg = "EOF buffer encountered. User tries to fetch data beyond the specified number of epochs."
     assert err_msg in str(info.value)