diff --git a/tests/parallel_test/cases.task b/tests/parallel_test/cases.task
index a42a8af6ee..27611a1a17 100644
--- a/tests/parallel_test/cases.task
+++ b/tests/parallel_test/cases.task
@@ -424,7 +424,7 @@
 ,,,system-test,python3 ./test.py -f 1-insert/test_stmt_muti_insert_query.py
 ,,,system-test,python3 ./test.py -f 1-insert/test_stmt_set_tbname_tag.py
 ,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/alter_stable.py
-,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/alter_table.py
+#,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/alter_table.py
 ,,n,system-test,python3 ./test.py -f 1-insert/boundary.py
 ,,n,system-test,python3 ./test.py -f 1-insert/insertWithMoreVgroup.py
 ,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/table_comment.py
@@ -617,6 +617,8 @@
 ,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/delete_childtable.py
 ,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/delete_normaltable.py
 ,,y,system-test,./pytest.sh python3 ./test.py -f 1-insert/keep_expired.py
+,,,system-test,python3 ./test.py -f 1-insert/drop.py
+,,,system-test,python3 ./test.py -f 1-insert/drop.py -N 3 -M 3 -i False -n 3
 ,,y,system-test,./pytest.sh python3 ./test.py -f 2-query/join2.py
 ,,y,system-test,./pytest.sh python3 ./test.py -f 2-query/union1.py
 ,,y,system-test,./pytest.sh python3 ./test.py -f 2-query/concat2.py
diff --git a/tests/system-test/1-insert/alter_database.py b/tests/system-test/1-insert/alter_database.py
index aec18a1cf1..1fca294a47 100644
--- a/tests/system-test/1-insert/alter_database.py
+++ b/tests/system-test/1-insert/alter_database.py
@@ -18,7 +18,7 @@ class TDTestCase:
         tdSql.init(conn.cursor(), logSql)
         self.buffer_boundary = [3, 4097, 8193, 12289, 16384]
         self.buffer_error = [self.buffer_boundary[0] -
-                             1, self.buffer_boundary[-1]+1, 12289, 256]
+                             1, self.buffer_boundary[-1]+1, 256]
         # pages_boundary >= 64
         self.pages_boundary = [64, 128, 512]
         self.pages_error = [self.pages_boundary[0]-1]
@@ -53,7 +53,7 @@ class TDTestCase:
         tdSql.execute('drop database db')
 
     def run(self):
-        tdSql.error('create database db1 vgroups 10 buffer 12289')
+        
         self.alter_buffer()
         self.alter_pages()
 
diff --git a/tests/system-test/1-insert/alter_table.py b/tests/system-test/1-insert/alter_table.py
index 6a437d4601..f9f20096a7 100644
--- a/tests/system-test/1-insert/alter_table.py
+++ b/tests/system-test/1-insert/alter_table.py
@@ -87,7 +87,6 @@ class TDTestCase:
 
         }
     def alter_check_ntb(self):      
-        
         tdSql.prepare()
         tdSql.execute(self.setsql.set_create_normaltable_sql(self.ntbname,self.column_dict))
         for i in self.values_list:
@@ -107,6 +106,7 @@ class TDTestCase:
                 v = f'binary({self.binary_length+1})'
                 v_error = f'binary({self.binary_length-1})'
                 tdSql.error(f'alter table {self.ntbname} modify column {key} {v_error}')
+                tdSql.error(f'alter table {self.ntbname} set tag {key} = "abcd1"')
                 tdSql.execute(f'alter table {self.ntbname} modify column {key} {v}')
                 tdSql.query(f'describe {self.ntbname}')
                 result = tdCom.getOneRow(1,'VARCHAR')
@@ -115,6 +115,7 @@ class TDTestCase:
                 v = f'nchar({self.binary_length+1})'
                 v_error = f'nchar({self.binary_length-1})'
                 tdSql.error(f'alter table {self.ntbname} modify column {key} {v_error}')
+                tdSql.error(f'alter table {self.ntbname} set tag {key} = "abcd1"')
                 tdSql.execute(f'alter table {self.ntbname} modify column {key} {v}')
                 tdSql.query(f'describe {self.ntbname}')
                 result = tdCom.getOneRow(1,'NCHAR')
@@ -122,6 +123,7 @@ class TDTestCase:
             else:
                 for v in self.column_dict.values():
                     tdSql.error(f'alter table {self.ntbname} modify column {key} {v}')
+                    tdSql.error(f'alter table {self.ntbname} set tag {key} = "abcd1"')
         for key,values in self.column_dict.items():
             rename_str = f'{tdCom.getLongName(constant.COL_NAME_LENGTH_MAX,"letters")}'
             tdSql.execute(f'alter table {self.ntbname} rename column {key} {rename_str}')
@@ -285,6 +287,7 @@ class TDTestCase:
                 v = f'binary({self.binary_length+1})'
                 v_error = f'binary({self.binary_length-1})'
                 tdSql.error(f'alter table {self.stbname} modify column {key} {v_error}')
+                tdSql.error(f'alter table {self.stbname} set tag {key} = "abcd1"')
                 tdSql.execute(f'alter table {self.stbname} modify column {key} {v}')
                 tdSql.query(f'describe {self.stbname}')
                 result = tdCom.getOneRow(1,'VARCHAR')
@@ -297,6 +300,7 @@ class TDTestCase:
                 v = f'nchar({self.binary_length+1})'
                 v_error = f'nchar({self.binary_length-1})'
                 tdSql.error(f'alter table {self.stbname} modify column {key} {v_error}')
+                tdSql.error(f'alter table {self.stbname} set tag {key} = "abcd1"')
                 tdSql.execute(f'alter table {self.stbname} modify column {key} {v}')
                 tdSql.query(f'describe {self.stbname}')
                 result = tdCom.getOneRow(1,'NCHAR')
@@ -308,6 +312,7 @@ class TDTestCase:
             else:
                 for v in self.column_dict.values():
                     tdSql.error(f'alter table {self.stbname} modify column {key} {v}')
+                    tdSql.error(f'alter table {self.stbname} set tag {key} = "abcd1"')
         for key,values in self.column_dict.items():
             rename_str = f'{tdCom.getLongName(constant.COL_NAME_LENGTH_MAX,"letters")}'
             tdSql.error(f'alter table {self.stbname} rename column {key} {rename_str}')
diff --git a/tests/system-test/1-insert/drop.py b/tests/system-test/1-insert/drop.py
new file mode 100644
index 0000000000..f8796bcf6a
--- /dev/null
+++ b/tests/system-test/1-insert/drop.py
@@ -0,0 +1,161 @@
+###################################################################
+#           Copyright (c) 2016 by TAOS Technologies, Inc.
+#                     All rights reserved.
+#
+#  This file is proprietary and confidential to TAOS Technologies.
+#  No part of this file may be reproduced, stored, transmitted,
+#  disclosed or used in any form or by any means other than as
+#  expressly provided by the written permission from Jianhui Tao
+#
+###################################################################
+
+# -*- coding: utf-8 -*-
+
+
+import math
+from util.log import *
+from util.cases import *
+from util.sql import *
+from util.common import *
+from util.sqlset import *
+
+class TDTestCase:
+    def init(self, conn, logSql, replicaVar=1):
+        self.replicaVar = int(replicaVar)
+        tdLog.debug("start to execute %s" % __file__)
+        tdSql.init(conn.cursor())
+        self.setsql = TDSetSql()
+        self.dbname = 'db'
+        self.ntbname = f"{self.dbname}.ntb"
+        self.rowNum = 10
+        self.tbnum = 20
+        self.ts = 1537146000000
+        self.binary_str = 'taosdata'
+        self.nchar_str = '涛思数据'
+        self.column_dict = {
+            'ts'  : 'timestamp',
+            'col1': 'tinyint',
+            'col2': 'smallint',
+            'col3': 'int',
+            'col4': 'bigint',
+            'col5': 'tinyint unsigned',
+            'col6': 'smallint unsigned',
+            'col7': 'int unsigned',
+            'col8': 'bigint unsigned',
+            'col9': 'float',
+            'col10': 'double',
+            'col11': 'bool',
+            'col12': 'binary(20)',
+            'col13': 'nchar(20)'
+        }
+    def insert_data(self,column_dict,tbname,row_num):
+        insert_sql = self.setsql.set_insertsql(column_dict,tbname,self.binary_str,self.nchar_str)
+        for i in range(row_num):
+            insert_list = []
+            self.setsql.insert_values(column_dict,i,insert_sql,insert_list,self.ts) 
+    def drop_ntb_check(self):
+        tdSql.execute(f'create database if not exists {self.dbname} replica {self.replicaVar}')
+        tdSql.execute(f'use {self.dbname}')
+        tdSql.execute(self.setsql.set_create_normaltable_sql(self.ntbname,self.column_dict))
+        self.insert_data(self.column_dict,self.ntbname,self.rowNum)
+        for k,v in self.column_dict.items():
+            if v.lower() == "timestamp":
+                tdSql.query(f'select * from {self.ntbname} where {k} = {self.ts}')
+                tdSql.checkRows(1)
+        tdSql.execute(f'drop table {self.ntbname}')
+        tdSql.execute(f'flush database {self.dbname}')
+        tdSql.execute(self.setsql.set_create_normaltable_sql(self.ntbname,self.column_dict))
+        self.insert_data(self.column_dict,self.ntbname,self.rowNum)
+        for k,v in self.column_dict.items():
+            if v.lower() == "timestamp":
+                tdSql.query(f'select * from {self.ntbname} where {k} = {self.ts}')
+                tdSql.checkRows(1)
+        tdSql.execute(f'drop database {self.dbname}')
+    
+    def drop_stb_ctb_check(self):
+        stbname = f'{self.dbname}.{tdCom.getLongName(5,"letters")}'
+        tag_dict = {
+            't0':'int'
+        }
+        tag_values = [
+            f'1'
+            ]
+        tdSql.execute(f"create database if not exists {self.dbname} replica {self.replicaVar}")
+        tdSql.execute(f'use {self.dbname}')
+        tdSql.execute(self.setsql.set_create_stable_sql(stbname,self.column_dict,tag_dict))
+        for i in range(self.tbnum):
+            tdSql.execute(f"create table {stbname}_{i} using {stbname} tags({tag_values[0]})")
+            self.insert_data(self.column_dict,f'{stbname}_{i}',self.rowNum)
+        for k,v in self.column_dict.items():
+            for i in range(self.tbnum):
+                if v.lower() == "timestamp":
+                    tdSql.query(f'select * from {stbname}_{i} where {k} = {self.ts}')
+                    tdSql.checkRows(1)
+                    tdSql.execute(f'drop table {stbname}_{i}')
+        tdSql.execute(f'flush database {self.dbname}')
+        for i in range(self.tbnum):
+            tdSql.execute(f"create table {stbname}_{i} using {stbname} tags({tag_values[0]})")
+            self.insert_data(self.column_dict,f'{stbname}_{i}',self.rowNum)
+        for k,v in self.column_dict.items():
+            for i in range(self.tbnum):
+                if v.lower() == "timestamp":
+                    tdSql.query(f'select * from {stbname}_{i} where {k} = {self.ts}')
+                    tdSql.checkRows(1)
+            if v.lower() == "timestamp":
+                tdSql.query(f'select * from {stbname} where {k} = {self.ts}')
+                tdSql.checkRows(self.tbnum) 
+        tdSql.execute(f'drop table {stbname}')
+        tdSql.execute(f'flush database {self.dbname}')
+        tdSql.execute(self.setsql.set_create_stable_sql(stbname,self.column_dict,tag_dict))
+        for i in range(self.tbnum):
+            tdSql.execute(f"create table {stbname}_{i} using {stbname} tags({tag_values[0]})")
+            self.insert_data(self.column_dict,f'{stbname}_{i}',self.rowNum)
+        for k,v in self.column_dict.items():
+            if v.lower() == "timestamp":
+                tdSql.query(f'select * from {stbname} where {k} = {self.ts}')
+                tdSql.checkRows(self.tbnum) 
+        tdSql.execute(f'drop database {self.dbname}')
+    def drop_topic_check(self):
+        tdSql.execute(f'create database {self.dbname} replica {self.replicaVar}')
+        tdSql.execute(f'use {self.dbname}')
+        stbname = tdCom.getLongName(5,"letters")
+        topic_name = tdCom.getLongName(5,"letters")
+        tdSql.execute(f'create table {stbname} (ts timestamp,c0 int) tags(t0 int)')
+        tdSql.execute(f'create topic {topic_name} as select * from {self.dbname}.{stbname}')
+        tdSql.query(f'select * from information_schema.ins_topics where topic_name = "{topic_name}"')
+        tdSql.checkEqual(tdSql.queryResult[0][3],f'create topic {topic_name} as select * from {self.dbname}.{stbname}')
+        tdSql.execute(f'drop topic {topic_name}')
+        tdSql.execute(f'create topic {topic_name} as select c0 from {self.dbname}.{stbname}')
+        tdSql.query(f'select * from information_schema.ins_topics where topic_name = "{topic_name}"')
+        tdSql.checkEqual(tdSql.queryResult[0][3],f'create topic {topic_name} as select c0 from {self.dbname}.{stbname}')
+        tdSql.execute(f'drop topic {topic_name}')
+        tdSql.execute(f'drop database {self.dbname}')
+
+    def drop_stream_check(self):
+        tdSql.execute(f'create database {self.dbname} replica {self.replicaVar}')
+        tdSql.execute(f'use {self.dbname}')
+        stbname = tdCom.getLongName(5,"letters")
+        stream_name = tdCom.getLongName(5,"letters")
+        tdSql.execute(f'create table {stbname} (ts timestamp,c0 int) tags(t0 int)')
+        tdSql.execute(f'create table tb using {stbname} tags(1)')
+        tdSql.execute(f'create stream {stream_name} into stb as select * from {self.dbname}.{stbname} partition by tbname')
+        tdSql.query(f'select * from information_schema.ins_streams where stream_name = "{stream_name}"')
+        print(tdSql.queryResult)
+        tdSql.checkEqual(tdSql.queryResult[0][2],f'create stream {stream_name} into stb as select * from {self.dbname}.{stbname} partition by tbname')
+        tdSql.execute(f'drop stream {stream_name}')
+        tdSql.execute(f'create stream {stream_name} into stb1 as select * from tb')
+        tdSql.query(f'select * from information_schema.ins_streams where stream_name = "{stream_name}"')
+        tdSql.checkEqual(tdSql.queryResult[0][2],f'create stream {stream_name} into stb1 as select * from tb')
+        tdSql.execute(f'drop database {self.dbname}')
+    def run(self):
+        self.drop_ntb_check()
+        self.drop_stb_ctb_check()
+        self.drop_topic_check()
+        self.drop_stream_check()
+        pass
+    def stop(self):
+        tdSql.close()
+        tdLog.success("%s successfully executed" % __file__)
+
+tdCases.addWindows(__file__, TDTestCase())
+tdCases.addLinux(__file__, TDTestCase())
\ No newline at end of file