diff --git a/src/connector/python/linux/python2/taos/cinterface.py b/src/connector/python/linux/python2/taos/cinterface.py
index 32859f6b340b4393b523d475bce1ac89cef1a040..269326535cfb39373544c71685e8a2b9e9b51db1 100644
--- a/src/connector/python/linux/python2/taos/cinterface.py
+++ b/src/connector/python/linux/python2/taos/cinterface.py
@@ -18,7 +18,7 @@ def _crow_timestamp_to_python(data, num_of_rows, nbytes=None, micro=False):
         _timestamp_converter = _convert_microsecond_to_datetime
 
     if num_of_rows > 0:
-        return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)][::-1]))
+        return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)][::1]))
     else:
         return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)]))
 
@@ -26,7 +26,7 @@ def _crow_bool_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C bool row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_bool))[:abs(num_of_rows)] ]
 
@@ -34,7 +34,7 @@ def _crow_tinyint_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C tinyint row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)] ]
     
@@ -42,7 +42,7 @@ def _crow_smallint_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C smallint row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)][::-1]]
+        return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)][::1]]
     else:
         return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)] ]
 
@@ -50,7 +50,7 @@ def _crow_int_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C int row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)] ]
 
@@ -58,7 +58,7 @@ def _crow_bigint_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C bigint row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)] ]
 
@@ -66,7 +66,7 @@ def _crow_float_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C float row to python row
     """
     if num_of_rows > 0:
-        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)][::-1] ]
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)] ]
 
@@ -74,7 +74,7 @@ def _crow_double_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C double row to python row
     """
     if num_of_rows > 0:
-        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)][::-1] ]
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)] ]
 
@@ -82,7 +82,7 @@ def _crow_binary_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C binary row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)][::-1]]
+        return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)][::1]]
     else:
         return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)]]
 
@@ -311,29 +311,24 @@ class CTaosInterface(object):
     @staticmethod
     def fetchBlock(result, fields):
         pblock = ctypes.c_void_p(0)
-        num_of_rows = CTaosInterface.libtaos.taos_fetch_block(
-            result, ctypes.byref(pblock))
-
-        if num_of_rows == 0:
+        pblock = CTaosInterface.libtaos.taos_fetch_row(result)  
+        if pblock : 
+            num_of_rows = 1
+            isMicro = (CTaosInterface.libtaos.taos_result_precision(result) == FieldType.C_TIMESTAMP_MICRO)
+            blocks = [None] * len(fields)
+            fieldL = CTaosInterface.libtaos.taos_fetch_lengths(result)
+            fieldLen = [ele for ele in ctypes.cast(fieldL,  ctypes.POINTER(ctypes.c_int))[:len(fields)]]
+            for i in range(len(fields)):
+                data = ctypes.cast(pblock, ctypes.POINTER(ctypes.c_void_p))[i]
+                if fields[i]['type'] not in _CONVERT_FUNC:
+                    raise DatabaseError("Invalid data type returned from database")
+                if data is None:
+                    blocks[i] = [None]
+                else:
+                    blocks[i] = _CONVERT_FUNC[fields[i]['type']](data, num_of_rows, fieldLen[i], isMicro)         
+        else:
             return None, 0
-
-        isMicro = (CTaosInterface.libtaos.taos_result_precision(result) == FieldType.C_TIMESTAMP_MICRO)
-        blocks = [None] * len(fields)
-        fieldL = CTaosInterface.libtaos.taos_fetch_lengths(result)
-        fieldLen = [ele for ele in ctypes.cast(fieldL,  ctypes.POINTER(ctypes.c_int))[:len(fields)]]
-        for i in range(len(fields)):
-            data = ctypes.cast(pblock, ctypes.POINTER(ctypes.c_void_p))[i]
-            if data == None:
-                blocks[i] = [None] * num_of_rows
-                continue
-
-            if fields[i]['type'] not in _CONVERT_FUNC:
-                raise DatabaseError("Invalid data type returned from database")
-            
-            blocks[i] = _CONVERT_FUNC[fields[i]['type']](data, num_of_rows, fieldLen[i], isMicro)
-
         return blocks, abs(num_of_rows)
-
     @staticmethod
     def freeResult(result):
         CTaosInterface.libtaos.taos_free_result(result)
diff --git a/src/connector/python/linux/python2/taos/cursor.py b/src/connector/python/linux/python2/taos/cursor.py
index 37c02d330e856717b5ed0bdac76723cf64d3860b..bc6670ca776a351c4739d61fc165d71334ceaa3b 100644
--- a/src/connector/python/linux/python2/taos/cursor.py
+++ b/src/connector/python/linux/python2/taos/cursor.py
@@ -1,6 +1,7 @@
 from .cinterface import CTaosInterface
 from .error import *
 from .constants import FieldType
+import threading
 
 
 class TDengineCursor(object):
@@ -35,6 +36,7 @@ class TDengineCursor(object):
         self._block_iter = 0
         self._affected_rows = 0
         self._logfile = ""
+        self._threadId = threading.get_ident()
 
         if connection is not None:
             self._connection = connection
@@ -42,7 +44,7 @@ class TDengineCursor(object):
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         if self._result is None or self._fields is None:
             raise OperationalError("Invalid use of fetch iterator")
 
@@ -137,7 +139,7 @@ class TDengineCursor(object):
         else:
             raise ProgrammingError(
                 CTaosInterface.errStr(
-                    self._result ), errno)
+                    self._result), errno)
 
     def executemany(self, operation, seq_of_parameters):
         """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.
@@ -148,6 +150,8 @@ class TDengineCursor(object):
         """Fetch the next row of a query result set, returning a single sequence, or None when no more data is available.
         """
         pass
+    def fetchmany(self):
+        pass
 
     def istype(self, col, dataType):
         if (dataType.upper() == "BOOL"):
@@ -180,9 +184,6 @@ class TDengineCursor(object):
 
         return False
 
-    def fetchmany(self):
-        pass
-
     def fetchall(self):
         """Fetch all (remaining) rows of a query result, returning them as a sequence of sequences (e.g. a list of tuples). Note that the cursor's arraysize attribute can affect the performance of this operation.
         """
@@ -201,8 +202,6 @@ class TDengineCursor(object):
             self._rowcount += num_of_fields
             for i in range(len(self._fields)):
                 buffer[i].extend(block[i])
-
-
         return list(map(tuple, zip(*buffer)))
 
     def nextset(self):
diff --git a/src/connector/python/windows/python2/taos/cinterface.py b/src/connector/python/windows/python2/taos/cinterface.py
index 6a9c5bfcef0d317844b6b58796f307e5cf155a43..084d38e41cee0e8c31a11d319d47e6bc5b125bd7 100644
--- a/src/connector/python/windows/python2/taos/cinterface.py
+++ b/src/connector/python/windows/python2/taos/cinterface.py
@@ -18,7 +18,7 @@ def _crow_timestamp_to_python(data, num_of_rows, nbytes=None, micro=False):
         _timestamp_converter = _convert_microsecond_to_datetime
 
     if num_of_rows > 0:
-        return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)][::-1]))
+        return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)][::1]))
     else:
         return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)]))
 
@@ -26,7 +26,7 @@ def _crow_bool_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C bool row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_bool))[:abs(num_of_rows)] ]
 
@@ -34,7 +34,7 @@ def _crow_tinyint_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C tinyint row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)] ]
     
@@ -42,7 +42,7 @@ def _crow_smallint_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C smallint row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)][::-1]]
+        return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)][::1]]
     else:
         return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)] ]
 
@@ -50,7 +50,7 @@ def _crow_int_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C int row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)] ]
 
@@ -58,7 +58,7 @@ def _crow_bigint_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C bigint row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)] ]
 
@@ -66,7 +66,7 @@ def _crow_float_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C float row to python row
     """
     if num_of_rows > 0:
-        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)][::-1] ]
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)] ]
 
@@ -74,7 +74,7 @@ def _crow_double_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C double row to python row
     """
     if num_of_rows > 0:
-        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)][::-1] ]
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)] ]
 
@@ -82,7 +82,7 @@ def _crow_binary_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C binary row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)][::-1]]
+        return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)][::1]]
     else:
         return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)]]
 
@@ -310,27 +310,23 @@ class CTaosInterface(object):
     @staticmethod
     def fetchBlock(result, fields):
         pblock = ctypes.c_void_p(0)
-        num_of_rows = CTaosInterface.libtaos.taos_fetch_block(
-            result, ctypes.byref(pblock))
-
-        if num_of_rows == 0:
+        pblock = CTaosInterface.libtaos.taos_fetch_row(result)  
+        if pblock : 
+            num_of_rows = 1
+            isMicro = (CTaosInterface.libtaos.taos_result_precision(result) == FieldType.C_TIMESTAMP_MICRO)
+            blocks = [None] * len(fields)
+            fieldL = CTaosInterface.libtaos.taos_fetch_lengths(result)
+            fieldLen = [ele for ele in ctypes.cast(fieldL,  ctypes.POINTER(ctypes.c_int))[:len(fields)]]
+            for i in range(len(fields)):
+                data = ctypes.cast(pblock, ctypes.POINTER(ctypes.c_void_p))[i]
+                if fields[i]['type'] not in _CONVERT_FUNC:
+                    raise DatabaseError("Invalid data type returned from database")
+                if data is None:
+                    blocks[i] = [None]
+                else:
+                    blocks[i] = _CONVERT_FUNC[fields[i]['type']](data, num_of_rows, fieldLen[i], isMicro)         
+        else:
             return None, 0
-
-        isMicro = (CTaosInterface.libtaos.taos_result_precision(result) == FieldType.C_TIMESTAMP_MICRO)
-        blocks = [None] * len(fields)
-        fieldL = CTaosInterface.libtaos.taos_fetch_lengths(result)
-        fieldLen = [ele for ele in ctypes.cast(fieldL,  ctypes.POINTER(ctypes.c_int))[:len(fields)]]
-        for i in range(len(fields)):
-            data = ctypes.cast(pblock, ctypes.POINTER(ctypes.c_void_p))[i]
-            if data == None:
-                blocks[i] = [None] * num_of_rows
-                continue
-
-            if fields[i]['type'] not in _CONVERT_FUNC:
-                raise DatabaseError("Invalid data type returned from database")
-            
-            blocks[i] = _CONVERT_FUNC[fields[i]['type']](data, num_of_rows, fieldLen[i], isMicro)
-
         return blocks, abs(num_of_rows)
 
     @staticmethod
diff --git a/src/connector/python/windows/python2/taos/cursor.py b/src/connector/python/windows/python2/taos/cursor.py
index 8714fe77cb739f23f79247a41d72aa127b6d6d25..35846cbe11f49386747a5a1f59e5529b84a741a0 100644
--- a/src/connector/python/windows/python2/taos/cursor.py
+++ b/src/connector/python/windows/python2/taos/cursor.py
@@ -1,5 +1,9 @@
 from .cinterface import CTaosInterface
 from .error import *
+from .constants import FieldType
+import threading
+
+# querySeqNum = 0
 
 class TDengineCursor(object):
     """Database cursor which is used to manage the context of a fetch operation.
@@ -32,6 +36,8 @@ class TDengineCursor(object):
         self._block_rows = -1
         self._block_iter = 0
         self._affected_rows = 0
+        self._logfile = ""
+        self._threadId = threading.get_ident()
 
         if connection is not None:
             self._connection = connection
@@ -39,7 +45,7 @@ class TDengineCursor(object):
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         if self._result is None or self._fields is None:
             raise OperationalError("Invalid use of fetch iterator")
 
diff --git a/src/connector/python/windows/python3/taos/cinterface.py b/src/connector/python/windows/python3/taos/cinterface.py
index fa7124431c92a179b2a0042b57e8ad45609ea352..68adf191c9bf696575254974ab6a544d5664faa5 100644
--- a/src/connector/python/windows/python3/taos/cinterface.py
+++ b/src/connector/python/windows/python3/taos/cinterface.py
@@ -18,7 +18,7 @@ def _crow_timestamp_to_python(data, num_of_rows, nbytes=None, micro=False):
         _timestamp_converter = _convert_microsecond_to_datetime
 
     if num_of_rows > 0:
-        return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)][::-1]))
+        return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)][::1]))
     else:
         return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)]))
 
@@ -26,7 +26,7 @@ def _crow_bool_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C bool row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_bool))[:abs(num_of_rows)] ]
 
@@ -34,7 +34,7 @@ def _crow_tinyint_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C tinyint row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)] ]
     
@@ -42,7 +42,7 @@ def _crow_smallint_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C smallint row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)][::-1]]
+        return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)][::1]]
     else:
         return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)] ]
 
@@ -50,7 +50,7 @@ def _crow_int_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C int row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)] ]
 
@@ -58,7 +58,7 @@ def _crow_bigint_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C bigint row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)][::-1] ]
+        return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_longlong))[:abs(num_of_rows)] ]
 
@@ -66,7 +66,7 @@ def _crow_float_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C float row to python row
     """
     if num_of_rows > 0:
-        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)][::-1] ]
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)] ]
 
@@ -74,7 +74,7 @@ def _crow_double_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C double row to python row
     """
     if num_of_rows > 0:
-        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)][::-1] ]
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)][::1] ]
     else:
         return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)] ]
 
@@ -82,7 +82,7 @@ def _crow_binary_to_python(data, num_of_rows, nbytes=None, micro=False):
     """Function to convert C binary row to python row
     """
     if num_of_rows > 0:
-        return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)][::-1]]
+        return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)][::1]]
     else:
         return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)]]
 
@@ -225,6 +225,7 @@ class CTaosInterface(object):
 
         if connection.value == None:
             print('connect to TDengine failed')
+            raise ConnectionError("connect to TDengine failed")
             # sys.exit(1)
         else:
             print('connect to TDengine success')
@@ -310,27 +311,23 @@ class CTaosInterface(object):
     @staticmethod
     def fetchBlock(result, fields):
         pblock = ctypes.c_void_p(0)
-        num_of_rows = CTaosInterface.libtaos.taos_fetch_block(
-            result, ctypes.byref(pblock))
-
-        if num_of_rows == 0:
+        pblock = CTaosInterface.libtaos.taos_fetch_row(result)  
+        if pblock : 
+            num_of_rows = 1
+            isMicro = (CTaosInterface.libtaos.taos_result_precision(result) == FieldType.C_TIMESTAMP_MICRO)
+            blocks = [None] * len(fields)
+            fieldL = CTaosInterface.libtaos.taos_fetch_lengths(result)
+            fieldLen = [ele for ele in ctypes.cast(fieldL,  ctypes.POINTER(ctypes.c_int))[:len(fields)]]
+            for i in range(len(fields)):
+                data = ctypes.cast(pblock, ctypes.POINTER(ctypes.c_void_p))[i]
+                if fields[i]['type'] not in _CONVERT_FUNC:
+                    raise DatabaseError("Invalid data type returned from database")
+                if data is None:
+                    blocks[i] = [None]
+                else:
+                    blocks[i] = _CONVERT_FUNC[fields[i]['type']](data, num_of_rows, fieldLen[i], isMicro)         
+        else:
             return None, 0
-
-        isMicro = (CTaosInterface.libtaos.taos_result_precision(result) == FieldType.C_TIMESTAMP_MICRO)
-        blocks = [None] * len(fields)
-        fieldL = CTaosInterface.libtaos.taos_fetch_lengths(result)
-        fieldLen = [ele for ele in ctypes.cast(fieldL,  ctypes.POINTER(ctypes.c_int))[:len(fields)]]
-        for i in range(len(fields)):
-            data = ctypes.cast(pblock, ctypes.POINTER(ctypes.c_void_p))[i]
-            if data == None:
-                blocks[i] = [None] * num_of_rows
-                continue
-
-            if fields[i]['type'] not in _CONVERT_FUNC:
-                raise DatabaseError("Invalid data type returned from database")
-            
-            blocks[i] = _CONVERT_FUNC[fields[i]['type']](data, num_of_rows, fieldLen[i], isMicro)
-
         return blocks, abs(num_of_rows)
 
     @staticmethod
diff --git a/src/connector/python/windows/python3/taos/cursor.py b/src/connector/python/windows/python3/taos/cursor.py
index c2c442b06ee71ae90ec63662886c709e38d4d2ad..b58b494cad0e0a2b664ef4765eae2baee27aa20b 100644
--- a/src/connector/python/windows/python3/taos/cursor.py
+++ b/src/connector/python/windows/python3/taos/cursor.py
@@ -1,5 +1,10 @@
 from .cinterface import CTaosInterface
 from .error import *
+from .constants import FieldType
+import threading
+
+# querySeqNum = 0
+
 
 class TDengineCursor(object):
     """Database cursor which is used to manage the context of a fetch operation.
@@ -32,6 +37,8 @@ class TDengineCursor(object):
         self._block_rows = -1
         self._block_iter = 0
         self._affected_rows = 0
+        self._logfile = ""
+        self._threadId = threading.get_ident()
 
         if connection is not None:
             self._connection = connection