diff --git a/paddle/fluid/framework/data_set.cc b/paddle/fluid/framework/data_set.cc
index e59c176344c202892c7264559ee9eeeccd292842..f185bf505f31c8cd1e69dacfd07490e73798a20d 100644
--- a/paddle/fluid/framework/data_set.cc
+++ b/paddle/fluid/framework/data_set.cc
@@ -50,6 +50,7 @@ DatasetImpl<T>::DatasetImpl() {
   min_merge_size_ = 2;
   parse_ins_id_ = false;
   parse_content_ = false;
+  preload_thread_num_ = 0;
 }
 
 // set filelist, file_idx_ will reset to zero.
@@ -120,6 +121,7 @@ void DatasetImpl<T>::SetMergeByInsId(
     const std::vector<std::string>& merge_slot_list, bool erase_duplicate_feas,
     int min_merge_size, bool keep_unmerged_ins) {
   merge_by_insid_ = true;
+  parse_ins_id_ = true;
   merge_slots_list_ = merge_slot_list;
   erase_duplicate_feas_ = erase_duplicate_feas;
   min_merge_size_ = min_merge_size;
@@ -202,10 +204,21 @@ void DatasetImpl<T>::LoadIntoMemory() {
 template <typename T>
 void DatasetImpl<T>::PreLoadIntoMemory() {
   VLOG(3) << "DatasetImpl<T>::PreLoadIntoMemory() begin";
-  preload_threads_.clear();
-  for (int64_t i = 0; i < thread_num_; ++i) {
-    preload_threads_.push_back(std::thread(
-        &paddle::framework::DataFeed::LoadIntoMemory, readers_[i].get()));
+  if (preload_thread_num_ != 0) {
+    CHECK(preload_thread_num_ == preload_readers_.size());
+    preload_threads_.clear();
+    for (int64_t i = 0; i < preload_thread_num_; ++i) {
+      preload_threads_.push_back(
+          std::thread(&paddle::framework::DataFeed::LoadIntoMemory,
+                      preload_readers_[i].get()));
+    }
+  } else {
+    CHECK(thread_num_ == readers_.size());
+    preload_threads_.clear();
+    for (int64_t i = 0; i < thread_num_; ++i) {
+      preload_threads_.push_back(std::thread(
+          &paddle::framework::DataFeed::LoadIntoMemory, readers_[i].get()));
+    }
   }
   VLOG(3) << "DatasetImpl<T>::PreLoadIntoMemory() end";
 }
@@ -420,6 +433,47 @@ void DatasetImpl<T>::DestroyReaders() {
   cur_channel_ = 1 - cur_channel_;
 }
 
+template <typename T>
+void DatasetImpl<T>::SetPreLoadThreadNum(int thread_num) {
+  preload_thread_num_ = thread_num;
+}
+
+template <typename T>
+void DatasetImpl<T>::CreatePreLoadReaders() {
+  VLOG(3) << "Begin CreatePreLoadReaders";
+  if (preload_thread_num_ == 0) {
+    preload_thread_num_ = thread_num_;
+  }
+  CHECK(preload_thread_num_ > 0) << "thread num should > 0";
+  CHECK(input_channel_ != nullptr);
+  preload_readers_.clear();
+  for (int i = 0; i < preload_thread_num_; ++i) {
+    preload_readers_.push_back(
+        DataFeedFactory::CreateDataFeed(data_feed_desc_.name()));
+    preload_readers_[i]->Init(data_feed_desc_);
+    preload_readers_[i]->SetThreadId(i);
+    preload_readers_[i]->SetThreadNum(preload_thread_num_);
+    preload_readers_[i]->SetFileListMutex(&mutex_for_pick_file_);
+    preload_readers_[i]->SetFileListIndex(&file_idx_);
+    preload_readers_[i]->SetFileList(filelist_);
+    preload_readers_[i]->SetParseInsId(parse_ins_id_);
+    preload_readers_[i]->SetInputChannel(input_channel_.get());
+    preload_readers_[i]->SetOutputChannel(nullptr);
+    preload_readers_[i]->SetConsumeChannel(nullptr);
+  }
+  VLOG(3) << "End CreatePreLoadReaders";
+}
+
+template <typename T>
+void DatasetImpl<T>::DestroyPreLoadReaders() {
+  VLOG(3) << "Begin DestroyPreLoadReaders";
+  preload_readers_.clear();
+  std::vector<std::shared_ptr<paddle::framework::DataFeed>>().swap(
+      preload_readers_);
+  file_idx_ = 0;
+  VLOG(3) << "End DestroyPreLoadReaders";
+}
+
 template <typename T>
 int64_t DatasetImpl<T>::GetMemoryDataSize() {
   return input_channel_->Size();
diff --git a/paddle/fluid/framework/data_set.h b/paddle/fluid/framework/data_set.h
index 8471616cd76cfbae82b1e5691b43d022e68cea9b..176a53f8f3dd595c5085e71693533a1129beba68 100644
--- a/paddle/fluid/framework/data_set.h
+++ b/paddle/fluid/framework/data_set.h
@@ -114,6 +114,12 @@ class Dataset {
   virtual int64_t GetShuffleDataSize() = 0;
   // merge by ins id
   virtual void MergeByInsId() = 0;
+  // create preload readers
+  virtual void CreatePreLoadReaders() = 0;
+  // destroy preload readers after prelaod done
+  virtual void DestroyPreLoadReaders() = 0;
+  // set preload thread num
+  virtual void SetPreLoadThreadNum(int thread_num) = 0;
 
  protected:
   virtual int ReceiveFromClient(int msg_type, int client_id,
@@ -172,11 +178,15 @@ class DatasetImpl : public Dataset {
   virtual int64_t GetMemoryDataSize();
   virtual int64_t GetShuffleDataSize();
   virtual void MergeByInsId() {}
+  virtual void CreatePreLoadReaders();
+  virtual void DestroyPreLoadReaders();
+  virtual void SetPreLoadThreadNum(int thread_num);
 
  protected:
   virtual int ReceiveFromClient(int msg_type, int client_id,
                                 const std::string& msg);
   std::vector<std::shared_ptr<paddle::framework::DataFeed>> readers_;
+  std::vector<std::shared_ptr<paddle::framework::DataFeed>> preload_readers_;
   paddle::framework::Channel<T> input_channel_;
   int channel_num_;
   std::vector<paddle::framework::Channel<T>> multi_output_channel_;
@@ -206,6 +216,7 @@ class DatasetImpl : public Dataset {
   int min_merge_size_;
   std::vector<std::string> merge_slots_list_;
   bool slots_shuffle_fea_eval_ = false;
+  int preload_thread_num_;
 };
 
 // use std::vector<MultiSlotType> or Record as data type
diff --git a/paddle/fluid/framework/fleet/fleet_wrapper.cc b/paddle/fluid/framework/fleet/fleet_wrapper.cc
index b072702c1033c1e42d8bb7ec4098bbc7270a78e2..0e1102f34126559a1a3f886c93fc0a001e20a19d 100644
--- a/paddle/fluid/framework/fleet/fleet_wrapper.cc
+++ b/paddle/fluid/framework/fleet/fleet_wrapper.cc
@@ -188,6 +188,7 @@ void FleetWrapper::PullSparseVarsSync(
     auto status = t.get();
     if (status != 0) {
       LOG(ERROR) << "fleet pull sparse failed, status[" << status << "]";
+      sleep(sleep_seconds_before_fail_exit_);
       exit(-1);
     }
   }
@@ -479,6 +480,7 @@ void FleetWrapper::LoadModel(const std::string& path, const int mode) {
   ret.wait();
   if (ret.get() != 0) {
     LOG(ERROR) << "load model from path:" << path << " failed";
+    sleep(sleep_seconds_before_fail_exit_);
     exit(-1);
   }
 #else
@@ -508,6 +510,7 @@ void FleetWrapper::SaveModel(const std::string& path, const int mode) {
   int32_t feasign_cnt = ret.get();
   if (feasign_cnt == -1) {
     LOG(ERROR) << "save model failed";
+    sleep(sleep_seconds_before_fail_exit_);
     exit(-1);
   }
 #else
@@ -524,6 +527,7 @@ double FleetWrapper::GetCacheThreshold() {
   ret.wait();
   if (cache_threshold < 0) {
     LOG(ERROR) << "get cache threshold failed";
+    sleep(sleep_seconds_before_fail_exit_);
     exit(-1);
   }
   return cache_threshold;
@@ -542,6 +546,7 @@ void FleetWrapper::CacheShuffle(int table_id, const std::string& path,
   int32_t feasign_cnt = ret.get();
   if (feasign_cnt == -1) {
     LOG(ERROR) << "cache shuffle failed";
+    sleep(sleep_seconds_before_fail_exit_);
     exit(-1);
   }
 #else
@@ -557,6 +562,7 @@ int32_t FleetWrapper::SaveCache(int table_id, const std::string& path,
   int32_t feasign_cnt = ret.get();
   if (feasign_cnt == -1) {
     LOG(ERROR) << "table save cache failed";
+    sleep(sleep_seconds_before_fail_exit_);
     exit(-1);
   }
   return feasign_cnt;
@@ -626,6 +632,7 @@ void FleetWrapper::ShrinkDenseTable(int table_id, Scope* scope,
   auto status = push_status.get();
   if (status != 0) {
     LOG(FATAL) << "push shrink dense param failed, status[" << status << "]";
+    sleep(sleep_seconds_before_fail_exit_);
     exit(-1);
   }
 #else
diff --git a/paddle/fluid/framework/fleet/fleet_wrapper.h b/paddle/fluid/framework/fleet/fleet_wrapper.h
index 6bc3c0910b52e695405c894f6276c4444e98d277..4fdfd6fc66ff9b4e07ef619968a88474bafee99b 100644
--- a/paddle/fluid/framework/fleet/fleet_wrapper.h
+++ b/paddle/fluid/framework/fleet/fleet_wrapper.h
@@ -55,7 +55,11 @@ namespace framework {
 class FleetWrapper {
  public:
   virtual ~FleetWrapper() {}
-  FleetWrapper() { scale_sparse_gradient_with_batch_size_ = true; }
+  FleetWrapper() {
+    scale_sparse_gradient_with_batch_size_ = true;
+    // trainer sleep some time for pslib core dump
+    sleep_seconds_before_fail_exit_ = 300;
+  }
   // Pull sparse variables from server in Sync mode
   // Param<in>: scope, table_id, var_names, fea_keys
   // Param<out>: fea_values
@@ -195,6 +199,7 @@ class FleetWrapper {
  protected:
   static bool is_initialized_;
   bool scale_sparse_gradient_with_batch_size_;
+  int32_t sleep_seconds_before_fail_exit_;
   DISABLE_COPY_AND_ASSIGN(FleetWrapper);
 };
 
diff --git a/paddle/fluid/framework/pull_dense_worker.cc b/paddle/fluid/framework/pull_dense_worker.cc
index 3fe0d516e2d5417b958dbfc1c6b13d15ed2be127..20d7f98e93695107637107c60f5ef42b8ce9293d 100644
--- a/paddle/fluid/framework/pull_dense_worker.cc
+++ b/paddle/fluid/framework/pull_dense_worker.cc
@@ -80,9 +80,6 @@ void PullDenseWorker::Stop() {
   if (running_) {
     running_ = false;
     t_.join();
-    // pull dense when stop, to make sure local dense params are same as
-    // pserver, so save paddle model will save dense model same as pserver
-    PullDense(true);
   }
 }
 
diff --git a/paddle/fluid/pybind/data_set_py.cc b/paddle/fluid/pybind/data_set_py.cc
index 9e114394dd9eb3039a46b10689c12a5fd92c6ab7..439824f768c1a9cd69342291e7a328924c0147f2 100644
--- a/paddle/fluid/pybind/data_set_py.cc
+++ b/paddle/fluid/pybind/data_set_py.cc
@@ -111,6 +111,13 @@ void BindDataset(py::module* m) {
       .def("slots_shuffle", &framework::Dataset::SlotsShuffle,
            py::call_guard<py::gil_scoped_release>())
       .def("set_fea_eval", &framework::Dataset::SetFeaEval,
+           py::call_guard<py::gil_scoped_release>())
+      .def("set_preload_thread_num", &framework::Dataset::SetPreLoadThreadNum,
+           py::call_guard<py::gil_scoped_release>())
+      .def("create_preload_readers", &framework::Dataset::CreatePreLoadReaders,
+           py::call_guard<py::gil_scoped_release>())
+      .def("destroy_preload_readers",
+           &framework::Dataset::DestroyPreLoadReaders,
            py::call_guard<py::gil_scoped_release>());
 }
 
diff --git a/python/paddle/fluid/dataset.py b/python/paddle/fluid/dataset.py
index 9e143954049dc94ccccf4b1c2476b37891d32b3c..486fe0995f6fdd4c7e5c8c4363fe6f176ea77608 100644
--- a/python/paddle/fluid/dataset.py
+++ b/python/paddle/fluid/dataset.py
@@ -423,10 +423,13 @@ class InMemoryDataset(DatasetBase):
         self._prepare_to_run()
         self.dataset.load_into_memory()
 
-    def preload_into_memory(self):
+    def preload_into_memory(self, thread_num=None):
         """
         Load data into memory in async mode
 
+        Args:
+            thread_num(int): preload thread num
+
         Examples:
             .. code-block:: python
 
@@ -438,6 +441,10 @@ class InMemoryDataset(DatasetBase):
               dataset.wait_preload_done()
         """
         self._prepare_to_run()
+        if thread_num is None:
+            thread_num = self.thread_num
+        self.dataset.set_preload_thread_num(thread_num)
+        self.dataset.create_preload_readers()
         self.dataset.preload_into_memory()
 
     def wait_preload_done(self):
@@ -455,6 +462,7 @@ class InMemoryDataset(DatasetBase):
               dataset.wait_preload_done()
         """
         self.dataset.wait_preload_done()
+        self.dataset.destroy_preload_readers()
 
     def local_shuffle(self):
         """
diff --git a/python/paddle/fluid/incubate/fleet/utils/fleet_util.py b/python/paddle/fluid/incubate/fleet/utils/fleet_util.py
index 4f651ffcbee10427147d59cfcef340a9ce9ce599..e3dc12f7cb7480531fc0c47673d6e9871e4819a7 100644
--- a/python/paddle/fluid/incubate/fleet/utils/fleet_util.py
+++ b/python/paddle/fluid/incubate/fleet/utils/fleet_util.py
@@ -926,7 +926,10 @@ class FleetUtil(object):
             if not client.is_exist(dest):
                 client.makedirs(dest)
 
-            client.upload(dest, model_name)
+            if os.path.isdir(model_name):
+                client.upload_dir(dest, model_name)
+            else:
+                client.upload(dest, model_name)
 
         fleet._role_maker._barrier_worker()
 
diff --git a/python/paddle/fluid/incubate/fleet/utils/hdfs.py b/python/paddle/fluid/incubate/fleet/utils/hdfs.py
index 3e7390b278887f498890782bad21df569f02f9e6..6b9efc4856ca49e5519e2664c2a92575e1fc4b4d 100644
--- a/python/paddle/fluid/incubate/fleet/utils/hdfs.py
+++ b/python/paddle/fluid/incubate/fleet/utils/hdfs.py
@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-"""HDFS Utils"""
+"""HDFS Utils."""
 
 import os
 import sys
@@ -84,7 +84,7 @@ class HDFSClient(object):
             ret_code, ret_out, ret_err = proc.returncode, output, errors
 
             _logger.info(
-                'Times: %d, Running command: %s. Return code: %d, Error: %s' %
+                'Times: %d, Running command: %s. Return code: %d, Msg: %s' %
                 (x, whole_commands, proc.returncode, errors))
 
             if ret_code == 0:
@@ -93,6 +93,13 @@ class HDFSClient(object):
         return ret_code, ret_out, ret_err
 
     def cat(self, hdfs_path=None):
+        """
+        cat hdfs file
+        Args:
+            hdfs_path(str): the hdfs file path
+        Returns:
+            file content
+        """
         if self.is_file(hdfs_path):
             exist_cmd = ['-cat', hdfs_path]
             returncode, output, errors = self.__run_hdfs_cmd(
@@ -101,8 +108,7 @@ class HDFSClient(object):
                 _logger.error("HDFS cat HDFS path: {} failed".format(hdfs_path))
                 return ""
             else:
-                _logger.error("HDFS cat HDFS path: {} succeed".format(
-                    hdfs_path))
+                _logger.info("HDFS cat HDFS path: {} succeed".format(hdfs_path))
                 return output.strip()
 
         else:
@@ -190,7 +196,7 @@ class HDFSClient(object):
         whether the remote HDFS path exists
 
         Args:
-        hdfs_path: HDFS path.
+            hdfs_path(str): HDFS path.
 
         Returns:
             True or False
@@ -224,9 +230,10 @@ class HDFSClient(object):
         Move a file or folder on HDFS.
 
         Args:
-        hdfs_path(str): HDFS path.
-        overwrite(bool|False): If the path already exists and overwrite is False, will return False.
-
+            hdfs_src_path(str): HDFS path
+            hdfs_dst_path(str): HDFS path
+            overwrite(bool|False): If the path already exists and overwrite is
+                                   False, will return False.
         Returns:
             True or False
         """
@@ -256,8 +263,9 @@ class HDFSClient(object):
     def make_local_dirs(local_path):
         """
         create a directiory local, is same to mkdir
+
         Args:
-            local_path: local path that wants to create a directiory.
+            local_path(str): local path that wants to create a directiory.
         """
         try:
             os.makedirs(local_path)
@@ -270,7 +278,8 @@ class HDFSClient(object):
         Create a remote directory, recursively if necessary.
 
         Args:
-        hdfs_path(str): Remote path. Intermediate directories will be created appropriately.
+            hdfs_path(str): Remote path. Intermediate directories will be
+                            created appropriately.
 
         Returns:
             True or False
@@ -290,7 +299,7 @@ class HDFSClient(object):
             _logger.error("HDFS mkdir path: {} failed".format(hdfs_path))
             return False
         else:
-            _logger.error("HDFS mkdir path: {} successfully".format(hdfs_path))
+            _logger.info("HDFS mkdir path: {} successfully".format(hdfs_path))
             return True
 
     def ls(self, hdfs_path):
@@ -298,7 +307,7 @@ class HDFSClient(object):
         ls directory contents about HDFS hdfs_path
 
         Args:
-        hdfs_path(str): Remote HDFS path will be ls.
+            hdfs_path(str): Remote HDFS path will be ls.
 
         Returns:
             List: a contents list about hdfs_path.
@@ -332,9 +341,8 @@ class HDFSClient(object):
         list directory contents about HDFS hdfs_path recursively
 
         Args:
-        hdfs_path(str): Remote HDFS path.
-        only_file(bool|True): will discard folders.
-        sort(bool|True): will be sorted by create time.
+            hdfs_path(str): Remote HDFS path.
+            excludes(list): excludes
 
         Returns:
             List: a contents list about hdfs_path.
@@ -373,7 +381,18 @@ class HDFSClient(object):
             return ret_lines
 
     @staticmethod
-    def split_flies(files, trainer_id, trainers):
+    def split_files(files, trainer_id, trainers):
+        """
+        split file list
+
+        Args:
+            files(list): file list
+            trainer_id(int): trainer mpi rank id
+            trainers(int): all trainers num
+
+        Returns:
+            fileist(list): file list of current trainer
+        """
         remainder = len(files) % trainers
         blocksize = len(files) / trainers
 
@@ -402,6 +421,8 @@ class HDFSClient(object):
             hdfs_path(str): path on hdfs
             local_path(str): path on local
             multi_processes(int|5): the download data process at the same time, default=5
+            overwrite(bool): is overwrite
+            retry_times(int): retry times
 
         Returns:
             List:
@@ -478,7 +499,7 @@ class HDFSClient(object):
             local_path(str): path on local
             multi_processes(int|5): the upload data process at the same time, default=5
             overwrite(bool|False): will overwrite file on HDFS or not
-            sync(bool|True): upload files sync or not.
+            retry_times(int): upload file max retry time.
 
         Returns:
             None
@@ -497,6 +518,15 @@ class HDFSClient(object):
             return True
 
         def get_local_files(path):
+            """
+            get local files
+
+            Args:
+                path(str): local path
+
+            Returns:
+                list of local files
+            """
             rlist = []
 
             if not os.path.exists(path):
@@ -537,6 +567,32 @@ class HDFSClient(object):
         _logger.info("Finish upload datas from {} to {}".format(local_path,
                                                                 hdfs_path))
 
+    def upload_dir(self, dest_dir, local_dir, overwrite=False):
+        """
+        upload dir to hdfs
+        Args:
+            dest_dir(str): hdfs dest dir
+            local_dir(str): hdfs local dir
+            overwrite(bool): is overwrite
+        Returns:
+            return code
+        """
+        local_dir = local_dir.rstrip("/")
+        dest_dir = dest_dir.rstrip("/")
+        local_basename = os.path.basename(local_dir)
+        if self.is_exist(dest_dir + "/" + local_basename) and overwrite:
+            self.delete(dest_dir + "/" + local_basename)
+        if not self.is_exist(dest_dir):
+            self.makedirs(dest_dir)
+        put_command = ["-put", local_dir, dest_dir]
+        returncode, output, errors = self.__run_hdfs_cmd(put_command,
+                                                         retry_times)
+        if returncode != 0:
+            _logger.error("Put local dir: {} to HDFS dir: {} failed".format(
+                local_dir, dest_dir))
+            return False
+        return True
+
 
 if __name__ == "__main__":
     hadoop_home = "/home/client/hadoop-client/hadoop/"
diff --git a/python/paddle/fluid/tests/unittests/test_dataset.py b/python/paddle/fluid/tests/unittests/test_dataset.py
index 2505cb6b3d3a28d89c90f8043cc60ff2731be91f..0958d33d1829b60c4c22b545677305fcbc250326 100644
--- a/python/paddle/fluid/tests/unittests/test_dataset.py
+++ b/python/paddle/fluid/tests/unittests/test_dataset.py
@@ -233,6 +233,14 @@ class TestDataset(unittest.TestCase):
             except Exception as e:
                 self.assertTrue(False)
 
+        dataset.set_merge_by_lineid(slots_vars)
+        dataset.preload_into_memory()
+        dataset.wait_preload_done()
+        dataset.release_memory()
+        dataset.preload_into_memory(1)
+        dataset.wait_preload_done()
+        fleet_ptr = fluid.core.Fleet()
+
         os.remove("./test_in_memory_dataset_run_a.txt")
         os.remove("./test_in_memory_dataset_run_b.txt")