diff --git a/src/client/src/tscProfile.c b/src/client/src/tscProfile.c
index 161591959b70aeda5a18093549a1c0a97e7f6891..e6d9aad6e22257005140c0b08c229111b3e1fe7c 100644
--- a/src/client/src/tscProfile.c
+++ b/src/client/src/tscProfile.c
@@ -100,7 +100,7 @@ void tscSaveSlowQuery(SSqlObj *pSql) {
   
   char *sql = malloc(sqlSize);
   if (sql == NULL) {
-    tscError("%p failed to allocate memory to sent slow to dnode", pSql);
+    tscError("%p failed to allocate memory to sent slow query to dnode", pSql);
     return;
   }
   
@@ -112,8 +112,8 @@ void tscSaveSlowQuery(SSqlObj *pSql) {
   } else {
     sqlLen += len;
   }
+  
   strcpy(sql + sqlLen, "')");
-
   taosTmrStart(tscSaveSlowQueryFp, 200, sql, tscTmr);
 }
 
diff --git a/src/connector/python/linux/python2/taos/cinterface.py b/src/connector/python/linux/python2/taos/cinterface.py
index 76c0a4be9dee698c1efeb92dd51dabfd34e9fb70..758244b6d85fb9cdc40daf10f38c8a595326528c 100644
--- a/src/connector/python/linux/python2/taos/cinterface.py
+++ b/src/connector/python/linux/python2/taos/cinterface.py
@@ -142,12 +142,13 @@ class CTaosInterface(object):
     libtaos.taos_fetch_fields.restype = ctypes.POINTER(TaosField)
     libtaos.taos_init.restype = None
     libtaos.taos_connect.restype = ctypes.c_void_p
-    libtaos.taos_use_result.restype = ctypes.c_void_p
+    #libtaos.taos_use_result.restype = ctypes.c_void_p
     libtaos.taos_fetch_row.restype = ctypes.POINTER(ctypes.c_void_p)
     libtaos.taos_errstr.restype = ctypes.c_char_p
     libtaos.taos_subscribe.restype = ctypes.c_void_p
     libtaos.taos_consume.restype = ctypes.c_void_p
     libtaos.taos_fetch_lengths.restype = ctypes.c_void_p
+    libtaos.taos_free_result.restype = None
 
     def __init__(self, config=None):
         '''
@@ -249,12 +250,12 @@ class CTaosInterface(object):
             raise AttributeError("sql is expected as a string")
         # finally:
         #     CTaosInterface.libtaos.close(connection)
-
+      
     @staticmethod
-    def affectedRows(connection):
+    def affectedRows(result):
         """The affected rows after runing query
         """
-        return CTaosInterface.libtaos.taos_affected_rows(connection)
+        return CTaosInterface.libtaos.taos_affected_rows(result)
 
     @staticmethod
     def subscribe(connection, restart, topic, sql, interval):
@@ -292,18 +293,17 @@ class CTaosInterface(object):
         CTaosInterface.libtaos.taos_unsubscribe(sub, 1 if keepProgress else 0)
 
     @staticmethod
-    def useResult(connection):
+    def useResult(result):
         '''Use result after calling self.query
         '''
-        result = ctypes.c_void_p(CTaosInterface.libtaos.taos_use_result(connection))
         fields = []
         pfields = CTaosInterface.fetchFields(result)
-        for i in range(CTaosInterface.fieldsCount(connection)):
+        for i in range(CTaosInterface.fieldsCount(result)):
             fields.append({'name': pfields[i].name.decode('utf-8'),
                            'bytes': pfields[i].bytes,
                            'type': ord(pfields[i].type)})
 
-        return result, fields
+        return fields
 
     @staticmethod
     def fetchBlock(result, fields):
@@ -337,8 +337,8 @@ class CTaosInterface(object):
         result.value = None
 
     @staticmethod
-    def fieldsCount(connection):
-        return CTaosInterface.libtaos.taos_field_count(connection)
+    def fieldsCount(result):
+        return CTaosInterface.libtaos.taos_field_count(result)
 
     @staticmethod
     def fetchFields(result):
@@ -386,29 +386,30 @@ class CTaosInterface(object):
     #         return (ctypes.cast(data,  ctypes.c_char_p).value).rstrip('\x00')
 
     @staticmethod
-    def errno(connection):
+    def errno(result):
         """Return the error number.
         """
-        return CTaosInterface.libtaos.taos_errno(connection)
+        return CTaosInterface.libtaos.taos_errno(result)
 
     @staticmethod
-    def errStr(connection):
+    def errStr(result):
         """Return the error styring
         """
-        return CTaosInterface.libtaos.taos_errstr(connection)
+        return CTaosInterface.libtaos.taos_errstr(result)
 
 
 if __name__ == '__main__':
     cinter = CTaosInterface()
     conn = cinter.connect()
+    result = cinter.query(conn, 'show databases')
 
-    print('Query return value: {}'.format(cinter.query(conn, 'show databases')))
-    print('Affected rows: {}'.format(cinter.affectedRows(conn)))
+    print('Query Affected rows: {}'.format(cinter.affectedRows(result)))
 
-    result, des = CTaosInterface.useResult(conn)
+    fields = CTaosInterface.useResult(result)
 
-    data, num_of_rows = CTaosInterface.fetchBlock(result, des)
+    data, num_of_rows = CTaosInterface.fetchBlock(result, fields)
 
     print(data)
 
+    cinter.freeresult(result)
     cinter.close(conn)
\ No newline at end of file
diff --git a/src/connector/python/linux/python2/taos/connection.py b/src/connector/python/linux/python2/taos/connection.py
index 04fbbdec04144624a0b1f4ba25083a91ade21cce..552250f1164ced467cd29b5084524985aca8848b 100644
--- a/src/connector/python/linux/python2/taos/connection.py
+++ b/src/connector/python/linux/python2/taos/connection.py
@@ -78,9 +78,7 @@ class TDengineConnection(object):
     def clear_result_set(self):
         """Clear unused result set on this connection.
         """
-        result = self._chandle.useResult(self._conn)[0]
-        if result:
-            self._chandle.freeResult(result)
+        pass
 
 if __name__ == "__main__":
     conn = TDengineConnection(host='192.168.1.107')
diff --git a/src/connector/python/linux/python2/taos/constants.py b/src/connector/python/linux/python2/taos/constants.py
index a994bceaf61894ac0bf9a719a574d00a09c584a5..feb7050a40b67f88a6d7ca859764fbbc6b36af1c 100644
--- a/src/connector/python/linux/python2/taos/constants.py
+++ b/src/connector/python/linux/python2/taos/constants.py
@@ -28,6 +28,6 @@ class FieldType(object):
     C_FLOAT_NULL = float('nan')
     C_DOUBLE_NULL = float('nan')
     C_BINARY_NULL = bytearray([int('0xff', 16)])
-    # Time precision definition
+    # Timestamp precision definition
     C_TIMESTAMP_MILLI = 0
     C_TIMESTAMP_MICRO = 1
diff --git a/src/connector/python/linux/python2/taos/cursor.py b/src/connector/python/linux/python2/taos/cursor.py
index 7ea52aa5add052284174354c3993c6b55512de8f..6bf8236ac99cd81377d26bfd1f203abea32749b5 100644
--- a/src/connector/python/linux/python2/taos/cursor.py
+++ b/src/connector/python/linux/python2/taos/cursor.py
@@ -116,25 +116,29 @@ class TDengineCursor(object):
         if params is not None:
             pass
 
-        res = CTaosInterface.query(self._connection._conn, stmt)
-
+        # global querySeqNum
+        # querySeqNum += 1
+        # localSeqNum = querySeqNum # avoid raice condition
+        # print("   >> Exec Query ({}): {}".format(localSeqNum, str(stmt)))
+        self._result = CTaosInterface.query(self._connection._conn, stmt)
+        # print("   << Query ({}) Exec Done".format(localSeqNum))
         if (self._logfile):
             with open(self._logfile, "a") as logfile:
                 logfile.write("%s;\n" % operation)
 
-        if res == 0:
-            if CTaosInterface.fieldsCount(self._connection._conn) == 0:
+        if self._result is not None:
+            if CTaosInterface.fieldsCount(self._result) == 0:
                 self._affected_rows += CTaosInterface.affectedRows(
-                    self._connection._conn)
-                return CTaosInterface.affectedRows(self._connection._conn)
+                    self._result )
+                return CTaosInterface.affectedRows(self._result )
             else:
-                self._result, self._fields = CTaosInterface.useResult(
-                    self._connection._conn)
+                self._fields = CTaosInterface.useResult(
+                    self._result)
                 return self._handle_result()
         else:
             raise ProgrammingError(
                 CTaosInterface.errStr(
-                    self._connection._conn))
+                    self._result ))
 
     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.
diff --git a/src/connector/python/linux/python3/taos/cinterface.py b/src/connector/python/linux/python3/taos/cinterface.py
index d516aad5a79fe19a54e3bcd97a0ef19f2ec6425b..b953aa11926ba4f0779bdcb94454bdbe96bd78b4 100644
--- a/src/connector/python/linux/python3/taos/cinterface.py
+++ b/src/connector/python/linux/python3/taos/cinterface.py
@@ -142,12 +142,13 @@ class CTaosInterface(object):
     libtaos.taos_fetch_fields.restype = ctypes.POINTER(TaosField)
     libtaos.taos_init.restype = None
     libtaos.taos_connect.restype = ctypes.c_void_p
-    libtaos.taos_use_result.restype = ctypes.c_void_p
+    #libtaos.taos_use_result.restype = ctypes.c_void_p
     libtaos.taos_fetch_row.restype = ctypes.POINTER(ctypes.c_void_p)
     libtaos.taos_errstr.restype = ctypes.c_char_p
     libtaos.taos_subscribe.restype = ctypes.c_void_p
     libtaos.taos_consume.restype = ctypes.c_void_p
     libtaos.taos_fetch_lengths.restype = ctypes.c_void_p
+    libtaos.taos_free_result.restype = None
 
     def __init__(self, config=None):
         '''
@@ -249,12 +250,12 @@ class CTaosInterface(object):
             raise AttributeError("sql is expected as a string")
         # finally:
         #     CTaosInterface.libtaos.close(connection)
-
+      
     @staticmethod
-    def affectedRows(connection):
+    def affectedRows(result):
         """The affected rows after runing query
         """
-        return CTaosInterface.libtaos.taos_affected_rows(connection)
+        return CTaosInterface.libtaos.taos_affected_rows(result)
 
     @staticmethod
     def subscribe(connection, restart, topic, sql, interval):
@@ -292,18 +293,17 @@ class CTaosInterface(object):
         CTaosInterface.libtaos.taos_unsubscribe(sub, 1 if keepProgress else 0)
 
     @staticmethod
-    def useResult(connection):
+    def useResult(result):
         '''Use result after calling self.query
         '''
-        result = ctypes.c_void_p(CTaosInterface.libtaos.taos_use_result(connection))
         fields = []
         pfields = CTaosInterface.fetchFields(result)
-        for i in range(CTaosInterface.fieldsCount(connection)):
+        for i in range(CTaosInterface.fieldsCount(result)):
             fields.append({'name': pfields[i].name.decode('utf-8'),
                            'bytes': pfields[i].bytes,
                            'type': ord(pfields[i].type)})
 
-        return result, fields
+        return fields
 
     @staticmethod
     def fetchBlock(result, fields):
@@ -337,8 +337,8 @@ class CTaosInterface(object):
         result.value = None
 
     @staticmethod
-    def fieldsCount(connection):
-        return CTaosInterface.libtaos.taos_field_count(connection)
+    def fieldsCount(result):
+        return CTaosInterface.libtaos.taos_field_count(result)
 
     @staticmethod
     def fetchFields(result):
@@ -386,29 +386,30 @@ class CTaosInterface(object):
     #         return (ctypes.cast(data,  ctypes.c_char_p).value).rstrip('\x00')
 
     @staticmethod
-    def errno(connection):
+    def errno(result):
         """Return the error number.
         """
-        return CTaosInterface.libtaos.taos_errno(connection)
+        return CTaosInterface.libtaos.taos_errno(result)
 
     @staticmethod
-    def errStr(connection):
+    def errStr(result):
         """Return the error styring
         """
-        return CTaosInterface.libtaos.taos_errstr(connection).decode('utf-8')
+        return CTaosInterface.libtaos.taos_errstr(result).decode('utf-8')
 
 
 if __name__ == '__main__':
     cinter = CTaosInterface()
     conn = cinter.connect()
+    result = cinter.query(conn, 'show databases')
 
-    print('Query return value: {}'.format(cinter.query(conn, 'show databases')))
-    print('Affected rows: {}'.format(cinter.affectedRows(conn)))
+    print('Query Affected rows: {}'.format(cinter.affectedRows(result)))
 
-    result, des = CTaosInterface.useResult(conn)
+    fields = CTaosInterface.useResult(result)
 
-    data, num_of_rows = CTaosInterface.fetchBlock(result, des)
+    data, num_of_rows = CTaosInterface.fetchBlock(result, fields)
 
     print(data)
 
+    cinter.freeresult(result)
     cinter.close(conn)
\ No newline at end of file
diff --git a/src/connector/python/linux/python3/taos/connection.py b/src/connector/python/linux/python3/taos/connection.py
index 04fbbdec04144624a0b1f4ba25083a91ade21cce..552250f1164ced467cd29b5084524985aca8848b 100644
--- a/src/connector/python/linux/python3/taos/connection.py
+++ b/src/connector/python/linux/python3/taos/connection.py
@@ -78,9 +78,7 @@ class TDengineConnection(object):
     def clear_result_set(self):
         """Clear unused result set on this connection.
         """
-        result = self._chandle.useResult(self._conn)[0]
-        if result:
-            self._chandle.freeResult(result)
+        pass
 
 if __name__ == "__main__":
     conn = TDengineConnection(host='192.168.1.107')
diff --git a/src/connector/python/linux/python3/taos/cursor.py b/src/connector/python/linux/python3/taos/cursor.py
index dc038a72bab142f128235fe67740f02f98216f8d..724cfe2163186cfaf584a061202291fe5da5907f 100644
--- a/src/connector/python/linux/python3/taos/cursor.py
+++ b/src/connector/python/linux/python3/taos/cursor.py
@@ -122,26 +122,26 @@ class TDengineCursor(object):
         # querySeqNum += 1
         # localSeqNum = querySeqNum # avoid raice condition
         # print("   >> Exec Query ({}): {}".format(localSeqNum, str(stmt)))
-        res = CTaosInterface.query(self._connection._conn, stmt)
+        self._result = CTaosInterface.query(self._connection._conn, stmt)
         # print("   << Query ({}) Exec Done".format(localSeqNum))
 
         if (self._logfile):
             with open(self._logfile, "a") as logfile:
                 logfile.write("%s;\n" % operation)
 
-        if res == 0:
-            if CTaosInterface.fieldsCount(self._connection._conn) == 0:
+        if self._result is not None:
+            if CTaosInterface.fieldsCount(self._result) == 0:
                 self._affected_rows += CTaosInterface.affectedRows(
-                    self._connection._conn)
-                return CTaosInterface.affectedRows(self._connection._conn)
+                    self._result )
+                return CTaosInterface.affectedRows(self._result )
             else:
-                self._result, self._fields = CTaosInterface.useResult(
-                    self._connection._conn)
+                self._fields = CTaosInterface.useResult(
+                    self._result)
                 return self._handle_result()
         else:
             raise ProgrammingError(
                 CTaosInterface.errStr(
-                    self._connection._conn))
+                    self._result ))
 
     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.
diff --git a/src/connector/python/windows/python2/taos/cinterface.py b/src/connector/python/windows/python2/taos/cinterface.py
index c4b8fa8328792a07e31c7584aafc5f32e7c168bf..e58ebbc8da4900a74224c8867837af7d36d6214c 100644
--- a/src/connector/python/windows/python2/taos/cinterface.py
+++ b/src/connector/python/windows/python2/taos/cinterface.py
@@ -142,12 +142,13 @@ class CTaosInterface(object):
     libtaos.taos_fetch_fields.restype = ctypes.POINTER(TaosField)
     libtaos.taos_init.restype = None
     libtaos.taos_connect.restype = ctypes.c_void_p
-    libtaos.taos_use_result.restype = ctypes.c_void_p
+    #libtaos.taos_use_result.restype = ctypes.c_void_p
     libtaos.taos_fetch_row.restype = ctypes.POINTER(ctypes.c_void_p)
     libtaos.taos_errstr.restype = ctypes.c_char_p
     libtaos.taos_subscribe.restype = ctypes.c_void_p
     libtaos.taos_consume.restype = ctypes.c_void_p
     libtaos.taos_fetch_lengths.restype = ctypes.c_void_p
+    libtaos.taos_free_result.restype = None
 
     def __init__(self, config=None):
         '''
@@ -251,10 +252,10 @@ class CTaosInterface(object):
         #     CTaosInterface.libtaos.close(connection)
 
     @staticmethod
-    def affectedRows(connection):
+    def affectedRows(result):
         """The affected rows after runing query
         """
-        return CTaosInterface.libtaos.taos_affected_rows(connection)
+        return CTaosInterface.libtaos.taos_affected_rows(result)
 
     @staticmethod
     def subscribe(connection, restart, topic, sql, interval):
@@ -292,18 +293,17 @@ class CTaosInterface(object):
         CTaosInterface.libtaos.taos_unsubscribe(sub, 1 if keepProgress else 0)
 
     @staticmethod
-    def useResult(connection):
+    def useResult(result):
         '''Use result after calling self.query
         '''
-        result = ctypes.c_void_p(CTaosInterface.libtaos.taos_use_result(connection))
         fields = []
         pfields = CTaosInterface.fetchFields(result)
-        for i in range(CTaosInterface.fieldsCount(connection)):
+        for i in range(CTaosInterface.fieldsCount(result)):
             fields.append({'name': pfields[i].name.decode('utf-8'),
                            'bytes': pfields[i].bytes,
                            'type': ord(pfields[i].type)})
 
-        return result, fields
+        return fields
 
     @staticmethod
     def fetchBlock(result, fields):
@@ -337,8 +337,8 @@ class CTaosInterface(object):
         result.value = None
 
     @staticmethod
-    def fieldsCount(connection):
-        return CTaosInterface.libtaos.taos_field_count(connection)
+    def fieldsCount(result):
+        return CTaosInterface.libtaos.taos_field_count(result)
 
     @staticmethod
     def fetchFields(result):
@@ -386,29 +386,30 @@ class CTaosInterface(object):
     #         return (ctypes.cast(data,  ctypes.c_char_p).value).rstrip('\x00')
 
     @staticmethod
-    def errno(connection):
+    def errno(result):
         """Return the error number.
         """
-        return CTaosInterface.libtaos.taos_errno(connection)
+        return CTaosInterface.libtaos.taos_errno(result)
 
     @staticmethod
-    def errStr(connection):
+    def errStr(result):
         """Return the error styring
         """
-        return CTaosInterface.libtaos.taos_errstr(connection)
+        return CTaosInterface.libtaos.taos_errstr(result)
 
 
 if __name__ == '__main__':
     cinter = CTaosInterface()
     conn = cinter.connect()
+    result = cinter.query(conn, 'show databases')
 
-    print('Query return value: {}'.format(cinter.query(conn, 'show databases')))
-    print('Affected rows: {}'.format(cinter.affectedRows(conn)))
+    print('Query Affected rows: {}'.format(cinter.affectedRows(result)))
 
-    result, des = CTaosInterface.useResult(conn)
+    fields = CTaosInterface.useResult(result)
 
-    data, num_of_rows = CTaosInterface.fetchBlock(result, des)
+    data, num_of_rows = CTaosInterface.fetchBlock(result, fields)
 
     print(data)
 
+    cinter.freeresult(result)
     cinter.close(conn)
\ No newline at end of file
diff --git a/src/connector/python/windows/python2/taos/connection.py b/src/connector/python/windows/python2/taos/connection.py
index e2783975d9c0f63c82a90b41a11fbaa0a3ffb5ac..d9576a553b810a975429b2cefc03e5e60f240a88 100644
--- a/src/connector/python/windows/python2/taos/connection.py
+++ b/src/connector/python/windows/python2/taos/connection.py
@@ -79,9 +79,7 @@ class TDengineConnection(object):
     def clear_result_set(self):
         """Clear unused result set on this connection.
         """
-        result = self._chandle.useResult(self._conn)[0]
-        if result:
-            self._chandle.freeResult(result)
+        pass
 
 if __name__ == "__main__":
     conn = TDengineConnection(host='192.168.1.107')
diff --git a/src/connector/python/windows/python2/taos/cursor.py b/src/connector/python/windows/python2/taos/cursor.py
index 976ec06707e7dd6f0a86a84ea9bce80e786875bc..0d7c882baf54bdb24c30eb2e07bcb425f1c04121 100644
--- a/src/connector/python/windows/python2/taos/cursor.py
+++ b/src/connector/python/windows/python2/taos/cursor.py
@@ -109,16 +109,16 @@ class TDengineCursor(object):
         if params is not None:
             pass
         
-        res = CTaosInterface.query(self._connection._conn, stmt)
-        if res == 0:
-            if CTaosInterface.fieldsCount(self._connection._conn) == 0:
-                self._affected_rows += CTaosInterface.affectedRows(self._connection._conn)
-                return CTaosInterface.affectedRows(self._connection._conn)
+        self._result = CTaosInterface.query(self._connection._conn, stmt)
+        if self._result is not None:
+            if CTaosInterface.fieldsCount(self._result) == 0:
+                self._affected_rows += CTaosInterface.affectedRows(self._result)
+                return CTaosInterface.affectedRows(self._result )
             else:
-                self._result, self._fields = CTaosInterface.useResult(self._connection._conn)
+                self._fields = CTaosInterface.useResult(self._result)
                 return self._handle_result()
         else:
-            raise ProgrammingError(CTaosInterface.errStr(self._connection._conn))
+            raise ProgrammingError(CTaosInterface.errStr(self._result))
 
     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.
diff --git a/src/connector/python/windows/python3/taos/cinterface.py b/src/connector/python/windows/python3/taos/cinterface.py
index d8c45f1171c11ffa67a7d1d5dccb47f51057bf2e..2217ad5c58d709ffef2ba5600ed323c9a5c8be65 100644
--- a/src/connector/python/windows/python3/taos/cinterface.py
+++ b/src/connector/python/windows/python3/taos/cinterface.py
@@ -142,12 +142,13 @@ class CTaosInterface(object):
     libtaos.taos_fetch_fields.restype = ctypes.POINTER(TaosField)
     libtaos.taos_init.restype = None
     libtaos.taos_connect.restype = ctypes.c_void_p
-    libtaos.taos_use_result.restype = ctypes.c_void_p
+    #libtaos.taos_use_result.restype = ctypes.c_void_p
     libtaos.taos_fetch_row.restype = ctypes.POINTER(ctypes.c_void_p)
     libtaos.taos_errstr.restype = ctypes.c_char_p
     libtaos.taos_subscribe.restype = ctypes.c_void_p
     libtaos.taos_consume.restype = ctypes.c_void_p
     libtaos.taos_fetch_lengths.restype = ctypes.c_void_p
+    libtaos.taos_free_result.restype = None
 
     def __init__(self, config=None):
         '''
@@ -251,10 +252,10 @@ class CTaosInterface(object):
         #     CTaosInterface.libtaos.close(connection)
 
     @staticmethod
-    def affectedRows(connection):
+    def affectedRows(result):
         """The affected rows after runing query
         """
-        return CTaosInterface.libtaos.taos_affected_rows(connection)
+        return CTaosInterface.libtaos.taos_affected_rows(result)
 
     @staticmethod
     def subscribe(connection, restart, topic, sql, interval):
@@ -292,18 +293,17 @@ class CTaosInterface(object):
         CTaosInterface.libtaos.taos_unsubscribe(sub, 1 if keepProgress else 0)
 
     @staticmethod
-    def useResult(connection):
+    def useResult(result):
         '''Use result after calling self.query
         '''
-        result = ctypes.c_void_p(CTaosInterface.libtaos.taos_use_result(connection))
         fields = []
         pfields = CTaosInterface.fetchFields(result)
-        for i in range(CTaosInterface.fieldsCount(connection)):
+        for i in range(CTaosInterface.fieldsCount(result)):
             fields.append({'name': pfields[i].name.decode('utf-8'),
                            'bytes': pfields[i].bytes,
                            'type': ord(pfields[i].type)})
 
-        return result, fields
+        return fields
 
     @staticmethod
     def fetchBlock(result, fields):
@@ -337,8 +337,8 @@ class CTaosInterface(object):
         result.value = None
 
     @staticmethod
-    def fieldsCount(connection):
-        return CTaosInterface.libtaos.taos_field_count(connection)
+    def fieldsCount(result):
+        return CTaosInterface.libtaos.taos_field_count(result)
 
     @staticmethod
     def fetchFields(result):
@@ -386,29 +386,30 @@ class CTaosInterface(object):
     #         return (ctypes.cast(data,  ctypes.c_char_p).value).rstrip('\x00')
 
     @staticmethod
-    def errno(connection):
+    def errno(result):
         """Return the error number.
         """
-        return CTaosInterface.libtaos.taos_errno(connection)
+        return CTaosInterface.libtaos.taos_errno(result)
 
     @staticmethod
-    def errStr(connection):
+    def errStr(result):
         """Return the error styring
         """
-        return CTaosInterface.libtaos.taos_errstr(connection).decode('utf-8')
+        return CTaosInterface.libtaos.taos_errstr(result).decode('utf-8')
 
 
 if __name__ == '__main__':
     cinter = CTaosInterface()
     conn = cinter.connect()
+    result = cinter.query(conn, 'show databases')
 
-    print('Query return value: {}'.format(cinter.query(conn, 'show databases')))
-    print('Affected rows: {}'.format(cinter.affectedRows(conn)))
+    print('Query Affected rows: {}'.format(cinter.affectedRows(result)))
 
-    result, des = CTaosInterface.useResult(conn)
+    fields = CTaosInterface.useResult(result)
 
-    data, num_of_rows = CTaosInterface.fetchBlock(result, des)
+    data, num_of_rows = CTaosInterface.fetchBlock(result, fields)
 
     print(data)
 
+    cinter.freeresult(result)
     cinter.close(conn)
\ No newline at end of file
diff --git a/src/connector/python/windows/python3/taos/connection.py b/src/connector/python/windows/python3/taos/connection.py
index e2783975d9c0f63c82a90b41a11fbaa0a3ffb5ac..d9576a553b810a975429b2cefc03e5e60f240a88 100644
--- a/src/connector/python/windows/python3/taos/connection.py
+++ b/src/connector/python/windows/python3/taos/connection.py
@@ -79,9 +79,7 @@ class TDengineConnection(object):
     def clear_result_set(self):
         """Clear unused result set on this connection.
         """
-        result = self._chandle.useResult(self._conn)[0]
-        if result:
-            self._chandle.freeResult(result)
+        pass
 
 if __name__ == "__main__":
     conn = TDengineConnection(host='192.168.1.107')
diff --git a/src/connector/python/windows/python3/taos/cursor.py b/src/connector/python/windows/python3/taos/cursor.py
index c7f34006422b559e21b75f36dcf81248e0b94713..ebc549ec988cf9ada7a2edaf14e8bcd66dcaefd4 100644
--- a/src/connector/python/windows/python3/taos/cursor.py
+++ b/src/connector/python/windows/python3/taos/cursor.py
@@ -109,16 +109,16 @@ class TDengineCursor(object):
         if params is not None:
             pass
         
-        res = CTaosInterface.query(self._connection._conn, stmt)
-        if res == 0:
-            if CTaosInterface.fieldsCount(self._connection._conn) == 0:
-                self._affected_rows += CTaosInterface.affectedRows(self._connection._conn)
-                return CTaosInterface.affectedRows(self._connection._conn)
+        self._result = CTaosInterface.query(self._connection._conn, stmt)
+        if self._result is not None:
+            if CTaosInterface.fieldsCount(self._result) == 0:
+                self._affected_rows += CTaosInterface.affectedRows(self._result )
+                return CTaosInterface.affectedRows(self._result )
             else:
-                self._result, self._fields = CTaosInterface.useResult(self._connection._conn)
+                self._fields = CTaosInterface.useResult(self._result )
                 return self._handle_result()
         else:
-            raise ProgrammingError(CTaosInterface.errStr(self._connection._conn))
+            raise ProgrammingError(CTaosInterface.errStr(self._result ))
 
     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.
diff --git a/src/kit/taosdump/taosdump.c b/src/kit/taosdump/taosdump.c
index 6b7ffb200155e293ae7e7881d8408335600ffeb7..7875ef732ce5e3b526675a26f1c2b7c1940ea445 100644
--- a/src/kit/taosdump/taosdump.c
+++ b/src/kit/taosdump/taosdump.c
@@ -544,7 +544,7 @@ int taosDumpOut(SDumpArguments *arguments) {
       taosDumpCreateDbClause(dbInfos[0], arguments->with_property, fp);
 
       sprintf(command, "use %s", dbInfos[0]->name);
-      if (taos_query(taos, command) != 0) {
+      if (taos_query(taos, command) == NULL ) {
         fprintf(stderr, "invalid database %s\n", dbInfos[0]->name);
         goto _exit_failure;
       }
@@ -1174,7 +1174,7 @@ int taosDumpIn(SDumpArguments *arguments) {
           tcommand = command;
         }
         taosReplaceCtrlChar(tcommand);
-        if (taos_query(taos, tcommand) != 0)
+        if (taos_query(taos, tcommand) == NULL)
           fprintf(stderr, "linenu: %" PRId64 " failed to run command %s reason:%s \ncontinue...\n", linenu, command,
                   taos_errstr(taos));
 
@@ -1250,7 +1250,7 @@ int taosDumpIn(SDumpArguments *arguments) {
       tcommand = command;
     }
     taosReplaceCtrlChar(lcommand);
-    if (taos_query(taos, tcommand) != 0)
+    if (taos_query(taos, tcommand) == NULL)
       fprintf(stderr, "linenu:%" PRId64 " failed to run command %s reason:%s \ncontinue...\n", linenu, command,
               taos_errstr(taos));
   }
diff --git a/src/query/inc/qExecutor.h b/src/query/inc/qExecutor.h
index 722a625526ab8ac20a0570f3db5338fc28cf3ca3..7ea272b8e8e320ac52accba70c9a094a315c44d6 100644
--- a/src/query/inc/qExecutor.h
+++ b/src/query/inc/qExecutor.h
@@ -116,11 +116,14 @@ typedef struct SQueryCostInfo {
   uint64_t loadDataInCacheSize;
   
   uint64_t loadDataTime;
-  uint64_t dataInRows;
-  uint64_t checkRows;
-  uint32_t dataBlocks;
+  uint64_t totalRows;
+  uint64_t totalCheckedRows;
+  uint32_t totalBlocks;
+  uint32_t loadBlocks;
   uint32_t loadBlockStatis;
   uint32_t discardBlocks;
+  uint64_t elapsedTime;
+  uint64_t computTime;
 } SQueryCostInfo;
 
 typedef struct SGroupItem {
@@ -168,7 +171,7 @@ typedef struct SQueryRuntimeEnv {
   SWindowResInfo       windowResInfo;
   STSBuf*              pTSBuf;
   STSCursor            cur;
-  SQueryCostInfo    summary;
+  SQueryCostInfo       summary;
   bool                 stableQuery;  // super table query or not
   void*                pQueryHandle;
   void*                pSecQueryHandle;  // another thread for
@@ -177,8 +180,6 @@ typedef struct SQueryRuntimeEnv {
 
 typedef struct SQInfo {
   void*   signature;
-  TSKEY   startTime;
-  TSKEY   elapsedTime;
   int32_t pointsInterpo;
   int32_t code;  // error code to returned to client
   sem_t   dataReady;
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 2e9069bbf1c3f12309e0b04fd0d1d6194c533f35..a7c9574d148a5fc4b915fa491a7b609cb419b1ca 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -1183,6 +1183,7 @@ static int32_t tableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBl
   
   STableQueryInfo* pTableQInfo = pQuery->current;
   SWindowResInfo*  pWindowResInfo = &pRuntimeEnv->windowResInfo;
+  pQuery->pos = QUERY_IS_ASC_QUERY(pQuery)? 0 : pDataBlockInfo->rows - 1;
   
   if (pQuery->numOfFilterCols > 0 || pRuntimeEnv->pTSBuf != NULL || isGroupbyNormalCol(pQuery->pGroupbyExpr)) {
     rowwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pWindowResInfo, pDataBlock);
@@ -1190,10 +1191,10 @@ static int32_t tableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBl
     blockwiseApplyFunctions(pRuntimeEnv, pStatis, pDataBlockInfo, pWindowResInfo, searchFn, pDataBlock);
   }
 
+  // update the lastkey of current table
   TSKEY lastKey = QUERY_IS_ASC_QUERY(pQuery) ? pDataBlockInfo->window.ekey : pDataBlockInfo->window.skey;
   pTableQInfo->lastKey = lastKey + GET_FORWARD_DIRECTION_FACTOR(pQuery->order.order);
 
-
   // interval query with limit applied
   int32_t numOfRes = 0;
   
@@ -2013,7 +2014,7 @@ SArray *loadDataBlockOnDemand(SQueryRuntimeEnv *pRuntimeEnv, void* pQueryHandle,
   
     if (*pStatis == NULL) { // data block statistics does not exist, load data block
       pDataBlock = tsdbRetrieveDataBlock(pQueryHandle, NULL);
-      pRuntimeEnv->summary.checkRows += pBlockInfo->rows;
+      pRuntimeEnv->summary.totalCheckedRows += pBlockInfo->rows;
     }
   } else {
     assert(r == BLK_DATA_ALL_NEEDED);
@@ -2032,7 +2033,7 @@ SArray *loadDataBlockOnDemand(SQueryRuntimeEnv *pRuntimeEnv, void* pQueryHandle,
       //        return DISK_DATA_DISCARDED;
     }
   
-    pRuntimeEnv->summary.checkRows += pBlockInfo->rows;
+    pRuntimeEnv->summary.totalCheckedRows += pBlockInfo->rows;
     pDataBlock = tsdbRetrieveDataBlock(pQueryHandle, NULL);
   }
 
@@ -2149,7 +2150,7 @@ static int64_t doScanAllDataBlocks(SQueryRuntimeEnv *pRuntimeEnv) {
 
   TsdbQueryHandleT pQueryHandle = IS_MASTER_SCAN(pRuntimeEnv)? pRuntimeEnv->pQueryHandle : pRuntimeEnv->pSecQueryHandle;
   while (tsdbNextDataBlock(pQueryHandle)) {
-    pRuntimeEnv->summary.dataBlocks += 1;
+    pRuntimeEnv->summary.totalBlocks += 1;
     if (isQueryKilled(GET_QINFO_ADDR(pRuntimeEnv))) {
       return 0;
     }
@@ -2185,12 +2186,10 @@ static int64_t doScanAllDataBlocks(SQueryRuntimeEnv *pRuntimeEnv) {
     ensureOutputBuffer(pRuntimeEnv, &blockInfo);
 
     SDataStatis *pStatis = NULL;
-    pQuery->pos = QUERY_IS_ASC_QUERY(pQuery)? 0 : blockInfo.rows - 1;
-    
     SArray *pDataBlock = loadDataBlockOnDemand(pRuntimeEnv, pQueryHandle, &blockInfo, &pStatis);
     int32_t numOfRes = tableApplyFunctionsOnBlock(pRuntimeEnv, &blockInfo, pStatis, binarySearchForKey, pDataBlock);
 
-    pRuntimeEnv->summary.dataInRows += blockInfo.rows;
+    pRuntimeEnv->summary.totalRows += blockInfo.rows;
     qTrace("QInfo:%p check data block, brange:%" PRId64 "-%" PRId64 ", numOfRows:%d, numOfRes:%d, lastKey:%"PRId64, GET_QINFO_ADDR(pRuntimeEnv),
            blockInfo.window.skey, blockInfo.window.ekey, blockInfo.rows, numOfRes, pQuery->current->lastKey);
 
@@ -3247,7 +3246,7 @@ void destroyTableQueryInfo(STableQueryInfo *pTableQueryInfo, int32_t numOfCols)
   free(pTableQueryInfo);
 }
 
-void restoreIntervalQueryRange(SQueryRuntimeEnv *pRuntimeEnv, STableQueryInfo *pTableQueryInfo) {
+void setCurrentQueryTable(SQueryRuntimeEnv *pRuntimeEnv, STableQueryInfo *pTableQueryInfo) {
   SQuery *pQuery = pRuntimeEnv->pQuery;
   pQuery->current = pTableQueryInfo;
   
@@ -3316,7 +3315,7 @@ static void setWindowResOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *
 
 int32_t setAdditionalInfo(SQInfo *pQInfo, STableId* pTableId, STableQueryInfo *pTableQueryInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
-  assert(pTableQueryInfo->lastKey >= 0);
+  assert(pTableQueryInfo->lastKey >= TSKEY_INITIAL_VAL);
 
   setTagVal(pRuntimeEnv, pTableId, pQInfo->tsdb);
 
@@ -3528,10 +3527,11 @@ static void updateWindowResNumOfRes(SQueryRuntimeEnv *pRuntimeEnv, STableQueryIn
   }
 }
 
-void stableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, STableQueryInfo *pTableQueryInfo,
-                                 SDataBlockInfo *pDataBlockInfo, SDataStatis *pStatis, SArray *pDataBlock,
-                                 __block_search_fn_t searchFn) {
+void stableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBlockInfo *pDataBlockInfo, SDataStatis *pStatis,
+    SArray *pDataBlock, __block_search_fn_t searchFn) {
   SQuery *         pQuery = pRuntimeEnv->pQuery;
+  STableQueryInfo* pTableQueryInfo = pQuery->current;
+  
   SWindowResInfo * pWindowResInfo = &pTableQueryInfo->windowResInfo;
   pQuery->pos = QUERY_IS_ASC_QUERY(pQuery)? 0 : pDataBlockInfo->rows - 1;
 
@@ -3685,8 +3685,9 @@ static void queryCostStatis(SQInfo *pQInfo) {
 //      pQInfo, pSummary->readDiskBlocks, pSummary->totalBlockSize, pSummary->loadBlocksUs / 1000.0,
 //      pSummary->skippedFileBlocks, pSummary->totalGenData);
   
-  qTrace("QInfo:%p cost: check blocks:%d, statis:%d, rows:%"PRId64", check rows:%"PRId64, pQInfo, pSummary->dataBlocks,
-         pSummary->loadBlockStatis, pSummary->dataInRows, pSummary->checkRows);
+  qTrace("QInfo:%p :cost summary: elpased time:%"PRId64" us, total blocks:%d, use block statis:%d, use block data:%d, "
+         "total rows:%"PRId64 ", check rows:%"PRId64, pQInfo, pSummary->elapsedTime, pSummary->totalBlocks,
+         pSummary->loadBlockStatis, pSummary->loadBlocks, pSummary->totalRows, pSummary->totalCheckedRows);
 
 //  qTrace("QInfo:%p cost: temp file:%d Bytes", pQInfo, pSummary->tmpBufferInDisk);
 //
@@ -4082,12 +4083,13 @@ static void enableExecutionForNextTable(SQueryRuntimeEnv *pRuntimeEnv) {
 static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
   SQuery *          pQuery = pRuntimeEnv->pQuery;
-
+  SQueryCostInfo* summary  = &pRuntimeEnv->summary;
+  
   int64_t st = taosGetTimestampMs();
 
   TsdbQueryHandleT pQueryHandle = IS_MASTER_SCAN(pRuntimeEnv)? pRuntimeEnv->pQueryHandle : pRuntimeEnv->pSecQueryHandle;
-  
   while (tsdbNextDataBlock(pQueryHandle)) {
+    summary->totalBlocks += 1;
     if (isQueryKilled(pQInfo)) {
       break;
     }
@@ -4119,11 +4121,9 @@ static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
     }
   
     assert(pTableQueryInfo != NULL);
-    restoreIntervalQueryRange(pRuntimeEnv, pTableQueryInfo);
-    printf("table:%d, groupIndex:%d, rows:%d\n", pTableQueryInfo->id.tid, pTableQueryInfo->groupIndex, blockInfo.tid);
+    setCurrentQueryTable(pRuntimeEnv, pTableQueryInfo);
 
     SDataStatis *pStatis = NULL;
-    
     SArray *pDataBlock = loadDataBlockOnDemand(pRuntimeEnv, pQueryHandle, &blockInfo, &pStatis);
 
     if (!isIntervalQuery(pQuery)) {
@@ -4132,15 +4132,14 @@ static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
     } else {  // interval query
       TSKEY nextKey = blockInfo.window.skey;
       setIntervalQueryRange(pQInfo, nextKey);
-      int32_t ret = setAdditionalInfo(pQInfo, &pTableQueryInfo->id, pTableQueryInfo);
-
-      if (ret != TSDB_CODE_SUCCESS) {
-        pQInfo->code = ret;
-        return taosGetTimestampMs() - st;
-      }
+      /*int32_t ret = */setAdditionalInfo(pQInfo, &pTableQueryInfo->id, pTableQueryInfo);
     }
 
-    stableApplyFunctionsOnBlock(pRuntimeEnv, pTableQueryInfo, &blockInfo, pStatis, pDataBlock, binarySearchForKey);
+    summary->totalRows += blockInfo.rows;
+    stableApplyFunctionsOnBlock(pRuntimeEnv, &blockInfo, pStatis, pDataBlock, binarySearchForKey);
+  
+    qTrace("QInfo:%p check data block, brange:%" PRId64 "-%" PRId64 ", numOfRows:%d, lastKey:%"PRId64, GET_QINFO_ADDR(pRuntimeEnv),
+           blockInfo.window.skey, blockInfo.window.ekey, blockInfo.rows, pQuery->current->lastKey);
   }
 
   int64_t et = taosGetTimestampMs();
@@ -4502,10 +4501,6 @@ static void multiTableQueryProcess(SQInfo *pQInfo) {
       copyFromWindowResToSData(pQInfo, pRuntimeEnv->windowResInfo.pResult);
     }
 
-    if (pQuery->rec.rows == 0) {
-      //      queryCostStatis(pSupporter);
-    }
-
     qTrace("QInfo:%p current:%lld, total:%lld", pQInfo, pQuery->rec.rows, pQuery->rec.total);
     return;
   }
@@ -4810,7 +4805,7 @@ static void tableQueryImpl(SQInfo *pQInfo) {
   }
 
   // record the total elapsed time
-  pQInfo->elapsedTime += (taosGetTimestampUs() - st);
+  pRuntimeEnv->summary.elapsedTime += (taosGetTimestampUs() - st);
   assert(pQInfo->groupInfo.numOfTables == 1);
 
   /* check if query is killed or not */
@@ -4840,13 +4835,10 @@ static void stableQueryImpl(SQInfo *pQInfo) {
   }
 
   // record the total elapsed time
-  pQInfo->elapsedTime += (taosGetTimestampUs() - st);
-  //  taosFillSetStartInfo(&pQInfo->runtimeEnv.pFillInfo, pQuery->size, pQInfo->query.fillType);
-
+  pQInfo->runtimeEnv.summary.elapsedTime += (taosGetTimestampUs() - st);
+  
   if (pQuery->rec.rows == 0) {
-    qTrace("QInfo:%p over, %d tables queried, %d points are returned", pQInfo, pQInfo->groupInfo.numOfTables,
-           pQuery->rec.total);
-    //    queryCostStatis(pSupporter);
+    qTrace("QInfo:%p over, %d tables queried, %d rows are returned", pQInfo, pQInfo->groupInfo.numOfTables, pQuery->rec.total);
   }
 }
 
@@ -5949,6 +5941,7 @@ int32_t qDumpRetrieveResult(qinfo_t qinfo, SRetrieveTableRsp **pRsp, int32_t *co
     return TSDB_CODE_INVALID_QHANDLE;
   }
 
+  SQueryRuntimeEnv* pRuntimeEnv = &pQInfo->runtimeEnv;
   SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
   size_t  size = getResultSize(pQInfo, &pQuery->rec.rows);
   size += sizeof(int32_t);
@@ -5962,7 +5955,7 @@ int32_t qDumpRetrieveResult(qinfo_t qinfo, SRetrieveTableRsp **pRsp, int32_t *co
   int32_t code = pQInfo->code;
   if (code == TSDB_CODE_SUCCESS) {
     (*pRsp)->offset = htobe64(pQuery->limit.offset);
-    (*pRsp)->useconds = htobe64(pQInfo->elapsedTime);
+    (*pRsp)->useconds = htobe64(pRuntimeEnv->summary.elapsedTime);
   } else {
     (*pRsp)->offset = 0;
     (*pRsp)->useconds = 0;