diff --git a/tests/pytest/query/queryJoin.py b/tests/pytest/query/queryJoin.py
index 17027cf498ff9e87b558866cd4d1e6a8c865afc0..a5e3ab21b3d7b639faf6e8b082a4ae58c5c430a6 100644
--- a/tests/pytest/query/queryJoin.py
+++ b/tests/pytest/query/queryJoin.py
@@ -95,14 +95,16 @@ class TDTestCase:
         tdSql.error(
             "select stb_t.ts, stb_t.dscrption, stb_t.temperature, stb_t.id, stb_p.dscrption, stb_p.pressure from stb_p, stb_t where stb_p.ts=stb_t.ts and stb_p.id = stb_t.id group by stb_t.id")
         tdSql.error(
-            "select stb_t.ts, stb_t.dscrption, stb_t.temperature, stb_t.id, stb_p.dscrption, stb_p.pressure from stb_p, stb_t where stb_p.ts=stb_t.ts and stb_p.id = stb_t.name;")
-        tdSql.error(
-            "select stb_t.ts, stb_t.dscrption, stb_t.temperature, stb_t.id, stb_p.dscrption, stb_p.pressure from stb_p, stb_t where stb_p.ts=stb_t.ts and stb_p.location = stb_t.name")
+            "select stb_t.ts, stb_t.dscrption, stb_t.temperature, stb_t.id, stb_p.dscrption, stb_p.pressure from stb_p, stb_t where stb_p.ts=stb_t.ts and stb_p.id = stb_t.name;")        
 
         tdSql.execute("alter table stb_t add tag pid int")
         tdSql.execute("alter table tb_t1 set tag pid=2")
         tdSql.execute("alter table tb_t2 set tag pid=1")
 
+        tdSql.query(
+            "select stb_t.ts, stb_t.dscrption, stb_t.temperature, stb_t.id, stb_p.dscrption, stb_p.pressure from stb_p, stb_t where stb_p.ts=stb_t.ts and stb_p.location = stb_t.name")
+        tdSql.checkRows(0)
+
         tdSql.query("select stb_t.ts, stb_t.dscrption, stb_t.temperature, stb_t.id, stb_p.dscrption, stb_p.pressure from stb_p, stb_t where stb_p.ts=stb_t.ts and stb_p.id = stb_t.pid")
         tdSql.checkRows(3)
 
diff --git a/tests/pytest/query/queryPerformance.py b/tests/pytest/query/queryPerformance.py
index a7fc08c5a39d7b9a59068463f521d83106865c2d..e09900acc4cde66b1f2505c0fb532889d2db81e4 100644
--- a/tests/pytest/query/queryPerformance.py
+++ b/tests/pytest/query/queryPerformance.py
@@ -11,6 +11,7 @@
 
 # -*- coding: utf-8 -*-
 
+
 import sys
 import os
 import taos
@@ -32,17 +33,23 @@ class taosdemoQueryPerformace:
 
     def query(self): 
         cursor = self.conn.cursor()                  
-        cursor.execute("use test")        
+        cursor.execute("use test")
 
         totalTime = 0
-        for i in range(100):
-            startTime = time.time()
+        for i in range(100):       
+            if(sys.argv[1] == '1'):
+                # root permission is required
+                os.system("echo 3 > /proc/sys/vm/drop_caches")  
+            startTime = time.time()            
             cursor.execute("select count(*) from test.meters")
             totalTime += time.time() - startTime
         print("query time for: select count(*) from test.meters %f seconds" % (totalTime / 100))
 
         totalTime = 0
         for i in range(100):
+            if(sys.argv[1] == '1'):  
+                # root permission is required              
+                os.system("echo 3 > /proc/sys/vm/drop_caches")
             startTime = time.time()
             cursor.execute("select avg(f1), max(f2), min(f3) from test.meters")
             totalTime += time.time() - startTime
@@ -50,6 +57,9 @@ class taosdemoQueryPerformace:
 
         totalTime = 0
         for i in range(100):
+            if(sys.argv[1] == '1'):
+                # root permission is required
+                os.system("echo 3 > /proc/sys/vm/drop_caches")
             startTime = time.time()
             cursor.execute("select count(*) from test.meters where loc='beijing'")
             totalTime += time.time() - startTime
@@ -57,6 +67,9 @@ class taosdemoQueryPerformace:
 
         totalTime = 0
         for i in range(100):
+            if(sys.argv[1] == '1'):
+                # root permission is required              
+                os.system("echo 3 > /proc/sys/vm/drop_caches")
             startTime = time.time()
             cursor.execute("select avg(f1), max(f2), min(f3) from test.meters where areaid=10")
             totalTime += time.time() - startTime
@@ -64,6 +77,9 @@ class taosdemoQueryPerformace:
 
         totalTime = 0
         for i in range(100):
+            if(sys.argv[1] == '1'):                
+                # root permission is required
+                os.system("echo 3 > /proc/sys/vm/drop_caches")
             startTime = time.time()
             cursor.execute("select avg(f1), max(f2), min(f3) from test.t10 interval(10s)")
             totalTime += time.time() - startTime
@@ -71,11 +87,34 @@ class taosdemoQueryPerformace:
 
         totalTime = 0
         for i in range(100):
+            if(sys.argv[1] == '1'):
+                # root permission is required           
+                os.system("echo 3 > /proc/sys/vm/drop_caches")
             startTime = time.time()
             cursor.execute("select last_row(*) from meters")
             totalTime += time.time() - startTime
         print("query time for: select last_row(*) from meters %f seconds" % (totalTime / 100))
 
+        totalTime = 0
+        for i in range(100):
+            if(sys.argv[1] == '1'):
+                # root permission is required           
+                os.system("echo 3 > /proc/sys/vm/drop_caches")
+            startTime = time.time()
+            cursor.execute("select * from meters")
+            totalTime += time.time() - startTime
+        print("query time for: select * from meters %f seconds" % (totalTime / 100))
+
+        totalTime = 0
+        for i in range(100):
+            if(sys.argv[1] == '1'):
+                # root permission is required        
+                os.system("echo 3 > /proc/sys/vm/drop_caches")
+            startTime = time.time()
+            cursor.execute("select avg(f1), max(f2), min(f3) from meters where ts <= '2017-07-15 10:40:01.000' and ts <= '2017-07-15 14:00:40.000'")
+            totalTime += time.time() - startTime
+        print("query time for: select avg(f1), max(f2), min(f3) from meters where ts <= '2017-07-15 10:40:01.000' and ts <= '2017-07-15 14:00:40.000' %f seconds" % (totalTime / 100))
+
 if __name__ == '__main__':
     perftest = taosdemoQueryPerformace()
     perftest.initConnection()