diff --git a/examples/highfreq/__init__.py b/examples/highfreq/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/examples/highfreq/highfreq_handler.py b/examples/highfreq/highfreq_handler.py
new file mode 100644
index 000000000..be2084626
--- /dev/null
+++ b/examples/highfreq/highfreq_handler.py
@@ -0,0 +1,174 @@
+from qlib.data.dataset.handler import DataHandler, DataHandlerLP
+from qlib.data.dataset.processor import Processor
+from qlib.utils import get_cls_kwargs
+from qlib.log import TimeInspector
+
+
+class HighFreqHandler(DataHandlerLP):
+    def __init__(
+        self,
+        instruments="csi300",
+        start_time=None,
+        end_time=None,
+        freq="1min",
+        infer_processors=[],
+        learn_processors=[],
+        fit_start_time=None,
+        fit_end_time=None,
+        drop_raw=True,
+    ):
+        def check_transform_proc(proc_l):
+            new_l = []
+            for p in proc_l:
+                p["kwargs"].update(
+                    {
+                        "fit_start_time": fit_start_time,
+                        "fit_end_time": fit_end_time,
+                    }
+                )
+                new_l.append(p)
+            return new_l
+
+        infer_processors = check_transform_proc(infer_processors)
+        learn_processors = check_transform_proc(learn_processors)
+
+        data_loader = {
+            "class": "QlibDataLoader",
+            "kwargs": {
+                "config": self.get_feature_config(),
+                "swap_level": False,
+            },
+        }
+        super().__init__(
+            instruments=instruments,
+            start_time=start_time,
+            end_time=end_time,
+            freq=freq,
+            data_loader=data_loader,
+            infer_processors=infer_processors,
+            learn_processors=learn_processors,
+            drop_raw=drop_raw,
+        )
+
+    def get_feature_config(self):
+        fields = []
+        names = []
+
+        template_if = "If(IsNull({1}), {0}, {1})"
+        template_paused = "Select(Or(IsNull($paused), Eq($paused, 0.0)), {0})"
+        template_fillnan = "BFillNan(FFillNan({0}))"
+        # Because there is no vwap field in the yahoo data, a method similar to Simpson integration is used to approximate vwap
+        simpson_vwap = "($open + 2*$high + 2*$low + $close)/6"
+
+        def get_normalized_price_feature(price_field, shift=0):
+            """Get normalized price feature ops"""
+            if shift == 0:
+                template_norm = "{0}/Ref(DayLast({1}), 240)"
+            else:
+                template_norm = "Ref({0}, " + str(shift) + ")/Ref(DayLast({1}), 240)"
+
+            feature_ops = template_norm.format(
+                template_if.format(
+                    template_fillnan.format(template_paused.format("$close")),
+                    template_paused.format(price_field),
+                ),
+                template_fillnan.format(template_paused.format("$close")),
+            )
+            return feature_ops
+
+        fields += [get_normalized_price_feature("$open", 0)]
+        fields += [get_normalized_price_feature("$high", 0)]
+        fields += [get_normalized_price_feature("$low", 0)]
+        fields += [get_normalized_price_feature("$close", 0)]
+        fields += [get_normalized_price_feature(simpson_vwap, 0)]
+        names += ["$open", "$high", "$low", "$close", "$vwap"]
+
+        fields += [get_normalized_price_feature("$open", 240)]
+        fields += [get_normalized_price_feature("$high", 240)]
+        fields += [get_normalized_price_feature("$low", 240)]
+        fields += [get_normalized_price_feature("$close", 240)]
+        fields += [get_normalized_price_feature(simpson_vwap, 240)]
+        names += ["$open_1", "$high_1", "$low_1", "$close_1", "$vwap_1"]
+
+        fields += [
+            "{0}/Ref(DayLast(Mean({0}, 7200)), 240)".format(
+                "If(IsNull({0}), 0, If(Or(Gt({1}, Mul(1.001, {3})), Lt({1}, Mul(0.999, {2}))), 0, {0}))".format(
+                    template_paused.format("$volume"),
+                    template_paused.format(simpson_vwap),
+                    template_paused.format("$low"),
+                    template_paused.format("$high"),
+                )
+            )
+        ]
+        names += ["$volume"]
+        fields += [
+            "Ref({0}, 240)/Ref(DayLast(Mean({0}, 7200)), 240)".format(
+                "If(IsNull({0}), 0, If(Or(Gt({1}, Mul(1.001, {3})), Lt({1}, Mul(0.999, {2}))), 0, {0}))".format(
+                    template_paused.format("$volume"),
+                    template_paused.format(simpson_vwap),
+                    template_paused.format("$low"),
+                    template_paused.format("$high"),
+                )
+            )
+        ]
+        names += ["$volume_1"]
+
+        fields += [template_paused.format("Date($close)")]
+        names += ["date"]
+        return fields, names
+
+
+class HighFreqBacktestHandler(DataHandler):
+    def __init__(
+        self,
+        instruments="csi300",
+        start_time=None,
+        end_time=None,
+        freq="1min",
+    ):
+        data_loader = {
+            "class": "QlibDataLoader",
+            "kwargs": {
+                "config": self.get_feature_config(),
+                "swap_level": False,
+            },
+        }
+        super().__init__(
+            instruments=instruments,
+            start_time=start_time,
+            end_time=end_time,
+            freq=freq,
+            data_loader=data_loader,
+        )
+
+    def get_feature_config(self):
+        fields = []
+        names = []
+
+        template_if = "If(IsNull({1}), {0}, {1})"
+        template_paused = "Select(Or(IsNull($paused), Eq($paused, 0.0)), {0})"
+        template_fillnan = "BFillNan(FFillNan({0}))"
+        # Because there is no vwap field in the yahoo data, a method similar to Simpson integration is used to approximate vwap
+        simpson_vwap = "($open + 2*$high + 2*$low + $close)/6"
+        fields += [
+            template_fillnan.format(template_paused.format("$close")),
+        ]
+        names += ["$close0"]
+        fields += [
+            template_if.format(
+                template_fillnan.format(template_paused.format("$close")),
+                template_paused.format(simpson_vwap),
+            )
+        ]
+        names += ["$vwap0"]
+        fields += [
+            "If(IsNull({0}), 0, If(Or(Gt({1}, Mul(1.001, {3})), Lt({1}, Mul(0.999, {2}))), 0, {0}))".format(
+                template_paused.format("$volume"),
+                template_paused.format(simpson_vwap),
+                template_paused.format("$low"),
+                template_paused.format("$high"),
+            )
+        ]
+        names += ["$volume0"]
+
+        return fields, names
diff --git a/examples/highfreq/highfreq_ops.py b/examples/highfreq/highfreq_ops.py
new file mode 100644
index 000000000..85ed63285
--- /dev/null
+++ b/examples/highfreq/highfreq_ops.py
@@ -0,0 +1,56 @@
+import numpy as np
+import pandas as pd
+import importlib
+from qlib.data.ops import ElemOperator, PairOperator
+from qlib.config import C
+from qlib.data.cache import H
+from qlib.data.data import Cal
+
+
+def get_calendar_day(freq="day", future=False):
+    flag = f"{freq}_future_{future}_day"
+    if flag in H["c"]:
+        _calendar = H["c"][flag]
+    else:
+        _calendar = np.array(list(map(lambda x: x.date(), Cal.load_calendar(freq, future))))
+        H["c"][flag] = _calendar
+    return _calendar
+
+
+class DayLast(ElemOperator):
+    def _load_internal(self, instrument, start_index, end_index, freq):
+        _calendar = get_calendar_day(freq=freq)
+        series = self.feature.load(instrument, start_index, end_index, freq)
+        return series.groupby(_calendar[series.index]).transform("last")
+
+
+class FFillNan(ElemOperator):
+    def _load_internal(self, instrument, start_index, end_index, freq):
+        series = self.feature.load(instrument, start_index, end_index, freq)
+        return series.fillna(method="ffill")
+
+
+class BFillNan(ElemOperator):
+    def _load_internal(self, instrument, start_index, end_index, freq):
+        series = self.feature.load(instrument, start_index, end_index, freq)
+        return series.fillna(method="bfill")
+
+
+class Date(ElemOperator):
+    def _load_internal(self, instrument, start_index, end_index, freq):
+        _calendar = get_calendar_day(freq=freq)
+        series = self.feature.load(instrument, start_index, end_index, freq)
+        return pd.Series(_calendar[series.index], index=series.index)
+
+
+class Select(PairOperator):
+    def _load_internal(self, instrument, start_index, end_index, freq):
+        series_condition = self.feature_left.load(instrument, start_index, end_index, freq)
+        series_feature = self.feature_right.load(instrument, start_index, end_index, freq)
+        return series_feature.loc[series_condition]
+
+
+class IsNull(ElemOperator):
+    def _load_internal(self, instrument, start_index, end_index, freq):
+        series = self.feature.load(instrument, start_index, end_index, freq)
+        return series.isnull()
diff --git a/examples/highfreq/highfreq_processor.py b/examples/highfreq/highfreq_processor.py
new file mode 100644
index 000000000..f0ab0dec2
--- /dev/null
+++ b/examples/highfreq/highfreq_processor.py
@@ -0,0 +1,72 @@
+import numpy as np
+import pandas as pd
+from qlib.data.dataset.processor import Processor
+from qlib.data.dataset.utils import fetch_df_by_index
+
+
+class HighFreqNorm(Processor):
+    def __init__(self, fit_start_time, fit_end_time):
+        self.fit_start_time = fit_start_time
+        self.fit_end_time = fit_end_time
+
+    def fit(self, df_features):
+        fetch_df = fetch_df_by_index(df_features, slice(self.fit_start_time, self.fit_end_time), level="datetime")
+        del df_features
+        df_values = fetch_df.values
+        names = {
+            "price": slice(0, 10),
+            "volume": slice(10, 12),
+        }
+        self.feature_med = {}
+        self.feature_std = {}
+        self.feature_vmax = {}
+        self.feature_vmin = {}
+        for name, name_val in names.items():
+            part_values = df_values[:, name_val].astype(np.float32)
+            if name == "volume":
+                part_values = np.log1p(part_values)
+            self.feature_med[name] = np.nanmedian(part_values)
+            part_values = part_values - self.feature_med[name]
+            self.feature_std[name] = np.nanmedian(np.absolute(part_values)) * 1.4826 + 1e-12
+            part_values = part_values / self.feature_std[name]
+            self.feature_vmax[name] = np.nanmax(part_values)
+            self.feature_vmin[name] = np.nanmin(part_values)
+
+    def __call__(self, df_features):
+        df_features.set_index("date", append=True, drop=True, inplace=True)
+        df_values = df_features.values
+        names = {
+            "price": slice(0, 10),
+            "volume": slice(10, 12),
+        }
+
+        for name, name_val in names.items():
+            if name == "volume":
+                df_values[:, name_val] = np.log1p(df_values[:, name_val])
+            df_values[:, name_val] -= self.feature_med[name]
+            df_values[:, name_val] /= self.feature_std[name]
+            slice0 = df_values[:, name_val] > 3.0
+            slice1 = df_values[:, name_val] > 3.5
+            slice2 = df_values[:, name_val] < -3.0
+            slice3 = df_values[:, name_val] < -3.5
+
+            df_values[:, name_val][slice0] = (
+                3.0 + (df_values[:, name_val][slice0] - 3.0) / (self.feature_vmax[name] - 3) * 0.5
+            )
+            df_values[:, name_val][slice1] = 3.5
+            df_values[:, name_val][slice2] = (
+                -3.0 - (df_values[:, name_val][slice2] + 3.0) / (self.feature_vmin[name] + 3) * 0.5
+            )
+            df_values[:, name_val][slice3] = -3.5
+        idx = df_features.index.droplevel("datetime").drop_duplicates()
+        idx.set_names(["instrument", "datetime"], inplace=True)
+
+        # Reshape is specifically for adapting to RL high-freq executor
+        feat = df_values[:, [0, 1, 2, 3, 4, 10]].reshape(-1, 6 * 240)
+        feat_1 = df_values[:, [5, 6, 7, 8, 9, 11]].reshape(-1, 6 * 240)
+        df_new_features = pd.DataFrame(
+            data=np.concatenate((feat, feat_1), axis=1),
+            index=idx,
+            columns=["FEATURE_%d" % i for i in range(12 * 240)],
+        ).sort_index()
+        return df_new_features
diff --git a/examples/highfreq/workflow.py b/examples/highfreq/workflow.py
new file mode 100644
index 000000000..e5fdcdb59
--- /dev/null
+++ b/examples/highfreq/workflow.py
@@ -0,0 +1,166 @@
+#  Copyright (c) Microsoft Corporation.
+#  Licensed under the MIT License.
+
+import sys
+import fire
+from pathlib import Path
+
+import qlib
+import pickle
+import numpy as np
+import pandas as pd
+from qlib.config import HIGH_FREQ_CONFIG
+from qlib.contrib.model.gbdt import LGBModel
+from qlib.contrib.data.handler import Alpha158
+from qlib.contrib.strategy.strategy import TopkDropoutStrategy
+from qlib.contrib.evaluate import (
+    backtest as normal_backtest,
+    risk_analysis,
+)
+
+from qlib.utils import init_instance_by_config, exists_qlib_data
+from qlib.data.dataset.handler import DataHandlerLP
+from qlib.data.ops import Operators
+from qlib.data.data import Cal
+from qlib.tests.data import GetData
+
+from highfreq_ops import get_calendar_day, DayLast, FFillNan, BFillNan, Date, Select, IsNull
+
+
+class HighfreqWorkflow(object):
+
+    SPEC_CONF = {"custom_ops": [DayLast, FFillNan, BFillNan, Date, Select, IsNull], "expression_cache": None}
+
+    MARKET = "all"
+    BENCHMARK = "SH000300"
+
+    start_time = "2020-09-14 00:00:00"
+    end_time = "2021-01-18 16:00:00"
+    train_end_time = "2020-11-30 16:00:00"
+    test_start_time = "2020-12-01 00:00:00"
+
+    DATA_HANDLER_CONFIG0 = {
+        "start_time": start_time,
+        "end_time": end_time,
+        "freq": "1min",
+        "fit_start_time": start_time,
+        "fit_end_time": train_end_time,
+        "instruments": MARKET,
+        "infer_processors": [{"class": "HighFreqNorm", "module_path": "highfreq_processor", "kwargs": {}}],
+    }
+    DATA_HANDLER_CONFIG1 = {
+        "start_time": start_time,
+        "end_time": end_time,
+        "freq": "1min",
+        "instruments": MARKET,
+    }
+
+    task = {
+        "dataset": {
+            "class": "DatasetH",
+            "module_path": "qlib.data.dataset",
+            "kwargs": {
+                "handler": {
+                    "class": "HighFreqHandler",
+                    "module_path": "highfreq_handler",
+                    "kwargs": DATA_HANDLER_CONFIG0,
+                },
+                "segments": {
+                    "train": (start_time, train_end_time),
+                    "test": (
+                        test_start_time,
+                        end_time,
+                    ),
+                },
+            },
+        },
+        "dataset_backtest": {
+            "class": "DatasetH",
+            "module_path": "qlib.data.dataset",
+            "kwargs": {
+                "handler": {
+                    "class": "HighFreqBacktestHandler",
+                    "module_path": "highfreq_handler",
+                    "kwargs": DATA_HANDLER_CONFIG1,
+                },
+                "segments": {
+                    "train": (start_time, train_end_time),
+                    "test": (
+                        test_start_time,
+                        end_time,
+                    ),
+                },
+            },
+        },
+    }
+
+    def _init_qlib(self):
+        """initialize qlib"""
+        # use yahoo_cn_1min data
+        QLIB_INIT_CONFIG = {**HIGH_FREQ_CONFIG, **self.SPEC_CONF}
+        provider_uri = QLIB_INIT_CONFIG.get("provider_uri")
+        if not exists_qlib_data(provider_uri):
+            print(f"Qlib data is not found in {provider_uri}")
+            GetData().qlib_data(target_dir=provider_uri, interval="1min", region=REG_CN)
+        qlib.init(**QLIB_INIT_CONFIG)
+
+    def _prepare_calender_cache(self):
+        """preload the calendar for cache"""
+
+        # This code used the copy-on-write feature of Linux to avoid calculating the calendar multiple times in the subprocess
+        # This code may accelerate, but may be not useful on Windows and Mac Os
+        Cal.calendar(freq="1min")
+        get_calendar_day(freq="1min")
+
+    def get_data(self):
+        """use dataset to get highreq data"""
+        self._init_qlib()
+        self._prepare_calender_cache()
+
+        dataset = init_instance_by_config(self.task["dataset"])
+        xtrain, xtest = dataset.prepare(["train", "test"])
+        print(xtrain, xtest)
+
+        dataset_backtest = init_instance_by_config(self.task["dataset_backtest"])
+        backtest_train, backtest_test = dataset_backtest.prepare(["train", "test"])
+        print(backtest_train, backtest_test)
+
+        del xtrain, xtest
+        del backtest_train, backtest_test
+
+    def dump_and_load_dataset(self):
+        """dump and load dataset state on disk"""
+        self._init_qlib()
+        self._prepare_calender_cache()
+        dataset = init_instance_by_config(self.task["dataset"])
+        dataset_backtest = init_instance_by_config(self.task["dataset_backtest"])
+
+        ##=============dump dataset=============
+        dataset.to_pickle(path="dataset.pkl")
+        dataset_backtest.to_pickle(path="dataset_backtest.pkl")
+
+        del dataset, dataset_backtest
+        ##=============reload dataset=============
+        with open("dataset.pkl", "rb") as file_dataset:
+            dataset = pickle.load(file_dataset)
+
+        with open("dataset_backtest.pkl", "rb") as file_dataset_backtest:
+            dataset_backtest = pickle.load(file_dataset_backtest)
+
+        self._prepare_calender_cache()
+        ##=============reload_dataset=============
+        dataset.init(init_type=DataHandlerLP.IT_LS)
+        dataset_backtest.init()
+
+        ##=============get data=============
+        xtrain, xtest = dataset.prepare(["train", "test"])
+        backtest_train, backtest_test = dataset_backtest.prepare(["train", "test"])
+
+        print(xtrain, xtest)
+        print(backtest_train, backtest_test)
+        del xtrain, xtest
+        del backtest_train, backtest_test
+
+
+if __name__ == "__main__":
+    fire.Fire(HighfreqWorkflow)
diff --git a/examples/workflow_by_code.py b/examples/workflow_by_code.py
index ea9c70083..6d166646c 100644
--- a/examples/workflow_by_code.py
+++ b/examples/workflow_by_code.py
@@ -17,7 +17,7 @@ from qlib.contrib.evaluate import (
 from qlib.utils import exists_qlib_data, init_instance_by_config, flatten_dict
 from qlib.workflow import R
 from qlib.workflow.record_temp import SignalRecord, PortAnaRecord
-
+from qlib.tests.data import GetData
 
 if __name__ == "__main__":
 
@@ -25,9 +25,6 @@ if __name__ == "__main__":
     provider_uri = "~/.qlib/qlib_data/cn_data"  # target_dir
     if not exists_qlib_data(provider_uri):
         print(f"Qlib data is not found in {provider_uri}")
-        sys.path.append(str(Path(__file__).resolve().parent.parent.joinpath("scripts")))
-        from get_data import GetData
-
         GetData().qlib_data(target_dir=provider_uri, region=REG_CN)
 
     qlib.init(provider_uri=provider_uri, region=REG_CN)
diff --git a/qlib/config.py b/qlib/config.py
index a65d41041..e7120c23a 100644
--- a/qlib/config.py
+++ b/qlib/config.py
@@ -193,6 +193,12 @@ MODE_CONF = {
     },
 }
 
+HIGH_FREQ_CONFIG = {
+    "provider_uri": "~/.qlib/qlib_data/yahoo_cn_1min",
+    "dataset_cache": None,
+    "expression_cache": "DiskExpressionCache",
+    "region": REG_CN,
+}
 
 _default_region_config = {
     REG_CN: {
@@ -291,12 +297,12 @@ class QlibConfig(Config):
 
     def register(self):
         from .utils import init_instance_by_config
-        from .data.ops import register_custom_ops
+        from .data.ops import register_all_ops
         from .data.data import register_all_wrappers
         from .workflow import R, QlibRecorder
         from .workflow.utils import experiment_exit_handler
 
-        register_custom_ops(self)
+        register_all_ops(self)
         register_all_wrappers(self)
         # set up QlibRecorder
         exp_manager = init_instance_by_config(self["exp_manager"])
diff --git a/qlib/contrib/data/handler.py b/qlib/contrib/data/handler.py
index 88a1f0680..23e37a5e4 100644
--- a/qlib/contrib/data/handler.py
+++ b/qlib/contrib/data/handler.py
@@ -49,6 +49,7 @@ class Alpha360(DataHandlerLP):
         instruments="csi500",
         start_time=None,
         end_time=None,
+        freq="day",
         infer_processors=_DEFAULT_INFER_PROCESSORS,
         learn_processors=_DEFAULT_LEARN_PROCESSORS,
         fit_start_time=None,
@@ -69,9 +70,10 @@ class Alpha360(DataHandlerLP):
         }
 
         super().__init__(
-            instruments,
-            start_time,
-            end_time,
+            instruments=instruments,
+            start_time=start_time,
+            end_time=end_time,
+            freq="day",
             data_loader=data_loader,
             learn_processors=learn_processors,
             infer_processors=infer_processors,
@@ -130,6 +132,7 @@ class Alpha158(DataHandlerLP):
         instruments="csi500",
         start_time=None,
         end_time=None,
+        freq="day",
         infer_processors=[],
         learn_processors=_DEFAULT_LEARN_PROCESSORS,
         fit_start_time=None,
@@ -147,9 +150,10 @@ class Alpha158(DataHandlerLP):
             },
         }
         super().__init__(
-            instruments,
-            start_time,
-            end_time,
+            instruments=instruments,
+            start_time=start_time,
+            end_time=end_time,
+            freq=freq,
             data_loader=data_loader,
             infer_processors=infer_processors,
             learn_processors=learn_processors,
diff --git a/qlib/data/base.py b/qlib/data/base.py
index 92fc57ffe..e318843c4 100644
--- a/qlib/data/base.py
+++ b/qlib/data/base.py
@@ -157,7 +157,7 @@ class Expression(abc.ABC):
 
     @abc.abstractmethod
     def _load_internal(self, instrument, start_index, end_index, freq):
-        pass
+        raise NotImplementedError("This function must be implemented in your newly defined feature")
 
     @abc.abstractmethod
     def get_longest_back_rolling(self):
diff --git a/qlib/data/data.py b/qlib/data/data.py
index ece3c3641..2a0e569ab 100644
--- a/qlib/data/data.py
+++ b/qlib/data/data.py
@@ -117,7 +117,7 @@ class CalendarProvider(abc.ABC):
         if flag in H["c"]:
             _calendar, _calendar_index = H["c"][flag]
         else:
-            _calendar = np.array(self._load_calendar(freq, future))
+            _calendar = np.array(self.load_calendar(freq, future))
             _calendar_index = {x: i for i, x in enumerate(_calendar)}  # for fast search
             H["c"][flag] = _calendar, _calendar_index
         return _calendar, _calendar_index
@@ -504,7 +504,7 @@ class LocalCalendarProvider(CalendarProvider):
         """Calendar file uri."""
         return os.path.join(C.get_data_path(), "calendars", "{}.txt")
 
-    def _load_calendar(self, freq, future):
+    def load_calendar(self, freq, future):
         """Load original calendar timestamp from file.
 
         Parameters
@@ -672,6 +672,8 @@ class LocalExpressionProvider(ExpressionProvider):
             series = series.astype(np.float32)
         except ValueError:
             pass
+        except TypeError:
+            pass
         if not series.empty:
             series = series.loc[start_index:end_index]
         return series
diff --git a/qlib/data/dataset/__init__.py b/qlib/data/dataset/__init__.py
index 96e4a6e41..117da764f 100644
--- a/qlib/data/dataset/__init__.py
+++ b/qlib/data/dataset/__init__.py
@@ -87,6 +87,10 @@ class DatasetH(Dataset):
         """
         super().__init__(handler, segments)
 
+    def init(self, **kwargs):
+        """Initialize the DatasetH, Only parameters belonging to handler.init will be passed in"""
+        self.handler.init(**kwargs)
+
     def setup_data(self, handler: Union[dict, DataHandler], segments: list):
         """
         Setup the underlying data.
@@ -116,8 +120,8 @@ class DatasetH(Dataset):
                         'outsample': ("2017-01-01", "2020-08-01",),
                     }
         """
-        self._handler = init_instance_by_config(handler, accept_types=DataHandler)
-        self._segments = segments.copy()
+        self.handler = init_instance_by_config(handler, accept_types=DataHandler)
+        self.segments = segments.copy()
 
     def _prepare_seg(self, slc: slice, **kwargs):
         """
@@ -127,7 +131,7 @@ class DatasetH(Dataset):
         ----------
         slc : slice
         """
-        return self._handler.fetch(slc, **kwargs)
+        return self.handler.fetch(slc, **kwargs)
 
     def prepare(
         self,
@@ -150,7 +154,7 @@ class DatasetH(Dataset):
             - ['train', 'valid']
 
         col_set : str
-            The col_set will be passed to self._handler when fetching data.
+            The col_set will be passed to self.handler when fetching data.
         data_key : str
             The data to fetch:  DK_*
             Default is DK_I, which indicate fetching data for **inference**.
@@ -166,16 +170,16 @@ class DatasetH(Dataset):
         logger = get_module_logger("DatasetH")
         fetch_kwargs = {"col_set": col_set}
         fetch_kwargs.update(kwargs)
-        if "data_key" in getfullargspec(self._handler.fetch).args:
+        if "data_key" in getfullargspec(self.handler.fetch).args:
             fetch_kwargs["data_key"] = data_key
         else:
             logger.info(f"data_key[{data_key}] is ignored.")
 
         # Handle all kinds of segments format
         if isinstance(segments, (list, tuple)):
-            return [self._prepare_seg(slice(*self._segments[seg]), **fetch_kwargs) for seg in segments]
+            return [self._prepare_seg(slice(*self.segments[seg]), **fetch_kwargs) for seg in segments]
         elif isinstance(segments, str):
-            return self._prepare_seg(slice(*self._segments[segments]), **fetch_kwargs)
+            return self._prepare_seg(slice(*self.segments[segments]), **fetch_kwargs)
         elif isinstance(segments, slice):
             return self._prepare_seg(segments, **fetch_kwargs)
         else:
@@ -409,7 +413,7 @@ class TSDatasetH(DatasetH):
 
     def setup_data(self, *args, **kwargs):
         super().setup_data(*args, **kwargs)
-        cal = self._handler.fetch(col_set=self._handler.CS_RAW).index.get_level_values("datetime").unique()
+        cal = self.handler.fetch(col_set=self.handler.CS_RAW).index.get_level_values("datetime").unique()
         cal = sorted(cal)
         # Get the datatime index for building timestamp
         self.cal = cal
diff --git a/qlib/data/dataset/handler.py b/qlib/data/dataset/handler.py
index 18f838300..abcd5a60c 100644
--- a/qlib/data/dataset/handler.py
+++ b/qlib/data/dataset/handler.py
@@ -57,6 +57,7 @@ class DataHandler(Serializable):
         instruments=None,
         start_time=None,
         end_time=None,
+        freq="day",
         data_loader: Tuple[dict, str, DataLoader] = None,
         init_data=True,
         fetch_orig=True,
@@ -70,6 +71,8 @@ class DataHandler(Serializable):
             start_time of the original data.
         end_time :
             end_time of the original data.
+        freq :
+            frequency of data
         data_loader : Tuple[dict, str, DataLoader]
             data loader to load the data.
         init_data :
@@ -92,6 +95,7 @@ class DataHandler(Serializable):
         self.instruments = instruments
         self.start_time = start_time
         self.end_time = end_time
+        self.freq = freq
         self.fetch_orig = fetch_orig
         if init_data:
             with TimeInspector.logt("Init data"):
@@ -119,7 +123,7 @@ class DataHandler(Serializable):
         # Setup data.
         # _data may be with multiple column index level. The outer level indicates the feature set name
         with TimeInspector.logt("Loading data"):
-            self._data = self.data_loader.load(self.instruments, self.start_time, self.end_time)
+            self._data = self.data_loader.load(self.instruments, self.start_time, self.end_time, self.freq)
         # TODO: cache
 
     CS_ALL = "__all"  # return all columns with single-level index column
@@ -258,10 +262,12 @@ class DataHandlerLP(DataHandler):
         instruments=None,
         start_time=None,
         end_time=None,
+        freq="day",
         data_loader: Tuple[dict, str, DataLoader] = None,
         infer_processors=[],
         learn_processors=[],
         process_type=PTYPE_A,
+        drop_raw=False,
         **kwargs,
     ):
         """
@@ -303,6 +309,8 @@ class DataHandlerLP(DataHandler):
             - self._learn will be processed by infer_processors + learn_processors
 
               - (e.g. self._infer processed by learn_processors )
+        drop_raw: bool
+            Whether to drop the raw data
         """
 
         # Setup preprocessor
@@ -319,7 +327,8 @@ class DataHandlerLP(DataHandler):
                 )
 
         self.process_type = process_type
-        super().__init__(instruments, start_time, end_time, data_loader, **kwargs)
+        self.drop_raw = drop_raw
+        super().__init__(instruments, start_time, end_time, freq, data_loader, **kwargs)
 
     def get_all_processors(self):
         return self.infer_processors + self.learn_processors
@@ -348,7 +357,7 @@ class DataHandlerLP(DataHandler):
         """
         # data for inference
         _infer_df = self._data
-        if len(self.infer_processors) > 0:  # avoid modifying the original  data
+        if len(self.infer_processors) > 0 and not self.drop_raw:  # avoid modifying the original  data
             _infer_df = _infer_df.copy()
 
         for proc in self.infer_processors:
@@ -378,6 +387,9 @@ class DataHandlerLP(DataHandler):
                 _learn_df = proc(_learn_df)
         self._learn = _learn_df
 
+        if self.drop_raw:
+            del self._data
+
     # init type
     IT_FIT_SEQ = "fit_seq"  # the input of `fit` will be the output of the previous processor
     IT_FIT_IND = "fit_ind"  # the input of `fit` will be the original df
@@ -416,6 +428,10 @@ class DataHandlerLP(DataHandler):
         # TODO: Be able to cache handler data. Save the memory for data processing
 
     def _get_df_by_key(self, data_key: str = DK_I) -> pd.DataFrame:
+        if data_key == self.DK_R and self.drop_raw:
+            raise AttributeError(
+                "DataHandlerLP has not attribute _data, please set drop_raw = False if you want to use raw data"
+            )
         df = getattr(self, {self.DK_R: "_data", self.DK_I: "_infer", self.DK_L: "_learn"}[data_key])
         return df
 
diff --git a/qlib/data/dataset/loader.py b/qlib/data/dataset/loader.py
index a51ea119a..3b33ff749 100644
--- a/qlib/data/dataset/loader.py
+++ b/qlib/data/dataset/loader.py
@@ -19,7 +19,7 @@ class DataLoader(abc.ABC):
     """
 
     @abc.abstractmethod
-    def load(self, instruments, start_time=None, end_time=None) -> pd.DataFrame:
+    def load(self, instruments, start_time=None, end_time=None, freq="day") -> pd.DataFrame:
         """
         load the data as pd.DataFrame.
 
@@ -94,7 +94,9 @@ class DLWParser(DataLoader):
         return exprs, names
 
     @abc.abstractmethod
-    def load_group_df(self, instruments, exprs: list, names: list, start_time=None, end_time=None) -> pd.DataFrame:
+    def load_group_df(
+        self, instruments, exprs: list, names: list, start_time=None, end_time=None, freq="day"
+    ) -> pd.DataFrame:
         """
         load the dataframe for specific group
 
@@ -114,25 +116,25 @@ class DLWParser(DataLoader):
         """
         pass
 
-    def load(self, instruments=None, start_time=None, end_time=None) -> pd.DataFrame:
+    def load(self, instruments=None, start_time=None, end_time=None, freq="day") -> pd.DataFrame:
         if self.is_group:
             df = pd.concat(
                 {
-                    grp: self.load_group_df(instruments, exprs, names, start_time, end_time)
+                    grp: self.load_group_df(instruments, exprs, names, start_time, end_time, freq)
                     for grp, (exprs, names) in self.fields.items()
                 },
                 axis=1,
             )
         else:
             exprs, names = self.fields
-            df = self.load_group_df(instruments, exprs, names, start_time, end_time)
+            df = self.load_group_df(instruments, exprs, names, start_time, end_time, freq)
         return df
 
 
 class QlibDataLoader(DLWParser):
     """Same as QlibDataLoader. The fields can be define by config"""
 
-    def __init__(self, config: Tuple[list, tuple, dict], filter_pipe=None):
+    def __init__(self, config: Tuple[list, tuple, dict], filter_pipe=None, swap_level=True):
         """
         Parameters
         ----------
@@ -140,11 +142,16 @@ class QlibDataLoader(DLWParser):
             Please refer to the doc of DLWParser
         filter_pipe :
             Filter pipe for the instruments
+        swap_level :
+            Whether to swap level of MultiIndex
         """
         self.filter_pipe = filter_pipe
+        self.swap_level = swap_level
         super().__init__(config)
 
-    def load_group_df(self, instruments, exprs: list, names: list, start_time=None, end_time=None) -> pd.DataFrame:
+    def load_group_df(
+        self, instruments, exprs: list, names: list, start_time=None, end_time=None, freq="day"
+    ) -> pd.DataFrame:
         if instruments is None:
             warnings.warn("`instruments` is not set, will load all stocks")
             instruments = "all"
@@ -153,9 +160,10 @@ class QlibDataLoader(DLWParser):
         elif self.filter_pipe is not None:
             warnings.warn("`filter_pipe` is not None, but it will not be used with `instruments` as list")
 
-        df = D.features(instruments, exprs, start_time, end_time)
+        df = D.features(instruments, exprs, start_time, end_time, freq)
         df.columns = names
-        df = df.swaplevel().sort_index()  # NOTE: always return <datetime, instrument>
+        if self.swap_level:
+            df = df.swaplevel().sort_index()  # NOTE: if swaplevel, return <datetime, instrument>
         return df
 
 
@@ -177,7 +185,7 @@ class StaticDataLoader(DataLoader):
         self.join = join
         self._data = None
 
-    def load(self, instruments=None, start_time=None, end_time=None) -> pd.DataFrame:
+    def load(self, instruments=None, start_time=None, end_time=None, freq="day") -> pd.DataFrame:
         self._maybe_load_raw_data()
         if instruments is None:
             df = self._data
diff --git a/qlib/data/ops.py b/qlib/data/ops.py
index 91f7349d2..940c24002 100644
--- a/qlib/data/ops.py
+++ b/qlib/data/ops.py
@@ -6,6 +6,7 @@ from __future__ import division
 from __future__ import print_function
 
 import sys
+import abc
 import numpy as np
 import pandas as pd
 
@@ -17,7 +18,7 @@ from ..log import get_module_logger
 try:
     from ._libs.rolling import rolling_slope, rolling_rsquare, rolling_resi
     from ._libs.expanding import expanding_slope, expanding_rsquare, expanding_resi
-except ImportError as err:
+except ImportError:
     print(
         "#### Do not import qlib package in the repository directory in case of importing qlib from . without compiling #####"
     )
@@ -32,12 +33,39 @@ np.seterr(invalid="ignore")
 class ElemOperator(ExpressionOps):
     """Element-wise Operator
 
+    Parameters
+    ----------
+    feature : Expression
+        feature instance
+
+    Returns
+    ----------
+    Expression
+        feature operation output
+    """
+
+    def __init__(self, feature):
+        self.feature = feature
+
+    def __str__(self):
+        return "{}({})".format(type(self).__name__, self.feature)
+
+    def get_longest_back_rolling(self):
+        return self.feature.get_longest_back_rolling()
+
+    def get_extended_window_size(self):
+        return self.feature.get_extended_window_size()
+
+
+class NpElemOperator(ElemOperator):
+    """Numpy Element-wise Operator
+
     Parameters
     ----------
     feature : Expression
         feature instance
     func : str
-        feature operation method
+        numpy feature operation method
 
     Returns
     ----------
@@ -48,22 +76,14 @@ class ElemOperator(ExpressionOps):
     def __init__(self, feature, func):
         self.feature = feature
         self.func = func
-
-    def __str__(self):
-        return "{}({})".format(type(self).__name__, self.feature)
+        super(NpElemOperator, self).__init__(feature)
 
     def _load_internal(self, instrument, start_index, end_index, freq):
         series = self.feature.load(instrument, start_index, end_index, freq)
         return getattr(np, self.func)(series)
 
-    def get_longest_back_rolling(self):
-        return self.feature.get_longest_back_rolling()
 
-    def get_extended_window_size(self):
-        return self.feature.get_extended_window_size()
-
-
-class Abs(ElemOperator):
+class Abs(NpElemOperator):
     """Feature Absolute Value
 
     Parameters
@@ -81,7 +101,7 @@ class Abs(ElemOperator):
         super(Abs, self).__init__(feature, "abs")
 
 
-class Sign(ElemOperator):
+class Sign(NpElemOperator):
     """Feature Sign
 
     Parameters
@@ -108,7 +128,7 @@ class Sign(ElemOperator):
         return getattr(np, self.func)(series)
 
 
-class Log(ElemOperator):
+class Log(NpElemOperator):
     """Feature Log
 
     Parameters
@@ -126,7 +146,7 @@ class Log(ElemOperator):
         super(Log, self).__init__(feature, "log")
 
 
-class Power(ElemOperator):
+class Power(NpElemOperator):
     """Feature Power
 
     Parameters
@@ -152,7 +172,7 @@ class Power(ElemOperator):
         return getattr(np, self.func)(series, self.exponent)
 
 
-class Mask(ElemOperator):
+class Mask(NpElemOperator):
     """Feature Mask
 
     Parameters
@@ -179,7 +199,7 @@ class Mask(ElemOperator):
         return self.feature.load(self.instrument, start_index, end_index, freq)
 
 
-class Not(ElemOperator):
+class Not(NpElemOperator):
     """Not Operator
 
     Parameters
@@ -218,28 +238,13 @@ class PairOperator(ExpressionOps):
         two features' operation output
     """
 
-    def __init__(self, feature_left, feature_right, func):
+    def __init__(self, feature_left, feature_right):
         self.feature_left = feature_left
         self.feature_right = feature_right
-        self.func = func
 
     def __str__(self):
         return "{}({},{})".format(type(self).__name__, self.feature_left, self.feature_right)
 
-    def _load_internal(self, instrument, start_index, end_index, freq):
-        assert any(
-            [isinstance(self.feature_left, Expression), self.feature_right, Expression]
-        ), "at least one of two inputs is Expression instance"
-        if isinstance(self.feature_left, Expression):
-            series_left = self.feature_left.load(instrument, start_index, end_index, freq)
-        else:
-            series_left = self.feature_left  # numeric value
-        if isinstance(self.feature_right, Expression):
-            series_right = self.feature_right.load(instrument, start_index, end_index, freq)
-        else:
-            series_right = self.feature_right
-        return getattr(np, self.func)(series_left, series_right)
-
     def get_longest_back_rolling(self):
         if isinstance(self.feature_left, Expression):
             left_br = self.feature_left.get_longest_back_rolling()
@@ -265,7 +270,46 @@ class PairOperator(ExpressionOps):
         return max(ll, rl), max(lr, rr)
 
 
-class Add(PairOperator):
+class NpPairOperator(PairOperator):
+    """Numpy Pair-wise operator
+
+    Parameters
+    ----------
+    feature_left : Expression
+        feature instance or numeric value
+    feature_right : Expression
+        feature instance or numeric value
+    func : str
+        operator function
+
+    Returns
+    ----------
+    Feature:
+        two features' operation output
+    """
+
+    def __init__(self, feature_left, feature_right, func):
+        self.feature_left = feature_left
+        self.feature_right = feature_right
+        self.func = func
+        super(NpPairOperator, self).__init__(feature_left, feature_right)
+
+    def _load_internal(self, instrument, start_index, end_index, freq):
+        assert any(
+            [isinstance(self.feature_left, Expression), self.feature_right, Expression]
+        ), "at least one of two inputs is Expression instance"
+        if isinstance(self.feature_left, Expression):
+            series_left = self.feature_left.load(instrument, start_index, end_index, freq)
+        else:
+            series_left = self.feature_left  # numeric value
+        if isinstance(self.feature_right, Expression):
+            series_right = self.feature_right.load(instrument, start_index, end_index, freq)
+        else:
+            series_right = self.feature_right
+        return getattr(np, self.func)(series_left, series_right)
+
+
+class Add(NpPairOperator):
     """Add Operator
 
     Parameters
@@ -285,7 +329,7 @@ class Add(PairOperator):
         super(Add, self).__init__(feature_left, feature_right, "add")
 
 
-class Sub(PairOperator):
+class Sub(NpPairOperator):
     """Subtract Operator
 
     Parameters
@@ -305,7 +349,7 @@ class Sub(PairOperator):
         super(Sub, self).__init__(feature_left, feature_right, "subtract")
 
 
-class Mul(PairOperator):
+class Mul(NpPairOperator):
     """Multiply Operator
 
     Parameters
@@ -325,7 +369,7 @@ class Mul(PairOperator):
         super(Mul, self).__init__(feature_left, feature_right, "multiply")
 
 
-class Div(PairOperator):
+class Div(NpPairOperator):
     """Division Operator
 
     Parameters
@@ -345,7 +389,7 @@ class Div(PairOperator):
         super(Div, self).__init__(feature_left, feature_right, "divide")
 
 
-class Greater(PairOperator):
+class Greater(NpPairOperator):
     """Greater Operator
 
     Parameters
@@ -365,7 +409,7 @@ class Greater(PairOperator):
         super(Greater, self).__init__(feature_left, feature_right, "maximum")
 
 
-class Less(PairOperator):
+class Less(NpPairOperator):
     """Less Operator
 
     Parameters
@@ -385,7 +429,7 @@ class Less(PairOperator):
         super(Less, self).__init__(feature_left, feature_right, "minimum")
 
 
-class Gt(PairOperator):
+class Gt(NpPairOperator):
     """Greater Than Operator
 
     Parameters
@@ -405,7 +449,7 @@ class Gt(PairOperator):
         super(Gt, self).__init__(feature_left, feature_right, "greater")
 
 
-class Ge(PairOperator):
+class Ge(NpPairOperator):
     """Greater Equal Than Operator
 
     Parameters
@@ -425,7 +469,7 @@ class Ge(PairOperator):
         super(Ge, self).__init__(feature_left, feature_right, "greater_equal")
 
 
-class Lt(PairOperator):
+class Lt(NpPairOperator):
     """Less Than Operator
 
     Parameters
@@ -445,7 +489,7 @@ class Lt(PairOperator):
         super(Lt, self).__init__(feature_left, feature_right, "less")
 
 
-class Le(PairOperator):
+class Le(NpPairOperator):
     """Less Equal Than Operator
 
     Parameters
@@ -465,7 +509,7 @@ class Le(PairOperator):
         super(Le, self).__init__(feature_left, feature_right, "less_equal")
 
 
-class Eq(PairOperator):
+class Eq(NpPairOperator):
     """Equal Operator
 
     Parameters
@@ -485,7 +529,7 @@ class Eq(PairOperator):
         super(Eq, self).__init__(feature_left, feature_right, "equal")
 
 
-class Ne(PairOperator):
+class Ne(NpPairOperator):
     """Not Equal Operator
 
     Parameters
@@ -505,7 +549,7 @@ class Ne(PairOperator):
         super(Ne, self).__init__(feature_left, feature_right, "not_equal")
 
 
-class And(PairOperator):
+class And(NpPairOperator):
     """And Operator
 
     Parameters
@@ -525,7 +569,7 @@ class And(PairOperator):
         super(And, self).__init__(feature_left, feature_right, "bitwise_and")
 
 
-class Or(PairOperator):
+class Or(NpPairOperator):
     """Or Operator
 
     Parameters
@@ -1451,6 +1495,9 @@ class OpsWrapper(object):
     def __init__(self):
         self._ops = {}
 
+    def reset(self):
+        self._ops = {}
+
     def register(self, ops_list):
         for operator in ops_list:
             if not issubclass(operator, ExpressionOps):
@@ -1469,12 +1516,15 @@ class OpsWrapper(object):
 
 
 Operators = OpsWrapper()
-Operators.register(OpsList)
 
 
-def register_custom_ops(C):
-    """register custom operator"""
+def register_all_ops(C):
+    """register all operator"""
     logger = get_module_logger("ops")
+
+    Operators.reset()
+    Operators.register(OpsList)
+
     if getattr(C, "custom_ops", None) is not None:
         Operators.register(C.custom_ops)
         logger.debug("register custom operator {}".format(C.custom_ops))
diff --git a/tests/test_dataset.py b/tests/test_dataset.py
index 10cd588e6..ed2f14d2f 100755
--- a/tests/test_dataset.py
+++ b/tests/test_dataset.py
@@ -66,7 +66,7 @@ class TestDataset(TestAutoData):
         # Check the data
         # Get data from DataFrame Directly
         data_from_df = (
-            tsdh._handler.fetch(data_key=DataHandlerLP.DK_L)
+            tsdh.handler.fetch(data_key=DataHandlerLP.DK_L)
             .loc(axis=0)["2015-01-01":"2016-12-31", "SZ300315"]
             .iloc[-30:]
             .values
diff --git a/tests/test_register_ops.py b/tests/test_register_ops.py
index cb172b2bb..7d3322ddc 100644
--- a/tests/test_register_ops.py
+++ b/tests/test_register_ops.py
@@ -26,9 +26,6 @@ class Diff(ElemOperator):
         a feature instance with first difference
     """
 
-    def __init__(self, feature):
-        super(Diff, self).__init__(feature, "diff")
-
     def _load_internal(self, instrument, start_index, end_index, freq):
         series = self.feature.load(instrument, start_index, end_index, freq)
         return series.diff()
@@ -50,9 +47,6 @@ class Distance(PairOperator):
         a feature instance with distance
     """
 
-    def __init__(self, feature_left, feature_right):
-        super(Distance, self).__init__(feature_left, feature_right, "distance")
-
     def _load_internal(self, instrument, start_index, end_index, freq):
         series_left = self.feature_left.load(instrument, start_index, end_index, freq)
         series_right = self.feature_right.load(instrument, start_index, end_index, freq)