diff --git a/client/ledis-py/ledis/client.py b/client/ledis-py/ledis/client.py
index 7d64457..4593a70 100644
--- a/client/ledis-py/ledis/client.py
+++ b/client/ledis-py/ledis/client.py
@@ -2,14 +2,12 @@ from __future__ import with_statement
 import datetime
 import time as mod_time
 from ledis._compat import (b, izip, imap, iteritems,
-                           basestring, long, nativestr, urlparse, bytes)
+                           basestring, long, nativestr, bytes)
 from ledis.connection import ConnectionPool, UnixDomainSocketConnection
 from ledis.exceptions import (
     ConnectionError,
     DataError,
     LedisError,
-    ResponseError,
-    ExecAbortError,
 )
 
 SYM_EMPTY = b('')
@@ -75,15 +73,18 @@ class Ledis(object):
     """
     RESPONSE_CALLBACKS = dict_merge(
         string_keys_to_dict(
-            'EXISTS EXPIRE EXPIREAT HEXISTS HMSET SETNX '
-            'PERSIST HPERSIST LPERSIST ZPERSIST BEXPIRE '
-            'BEXPIREAT BPERSIST BDELETE',
+            'EXISTS HEXISTS SISMEMBER  HMSET SETNX'
+            'PERSIST HPERSIST LPERSIST ZPERSIST  SPERSIST BPERSIST'
+            'EXPIRE LEXPIRE HEXPIRE SEXPIRE ZEXPIRE BEXPIRE'
+            'EXPIREAT LBEXPIREAT HEXPIREAT SEXPIREAT ZEXPIREAT BEXPIREAT',
             bool
         ),
         string_keys_to_dict(
-            'DECRBY DEL HDEL HLEN INCRBY LLEN '
-            'ZADD ZCARD ZREM ZREMRANGEBYRANK ZREMRANGEBYSCORE'
-            'LMCLEAR HMCLEAR ZMCLEAR BCOUNT BGETBIT BSETBIT BOPT BMSETBIT',
+            'DECRBY DEL HDEL HLEN INCRBY LLEN ZADD ZCARD ZREM'
+            'ZREMRANGEBYRANK ZREMRANGEBYSCORE LMCLEAR HMCLEAR'
+            'ZMCLEAR BCOUNT BGETBIT BSETBIT BOPT BMSETBIT'
+            'SADD SCARD SDIFFSTORE SINTERSTORE SUNIONSTORE SREM'
+            'SCLEAR SMLEAR BDELETE',
             int
         ),
         string_keys_to_dict(
@@ -94,6 +95,10 @@ class Ledis(object):
             'MSET SELECT ',
             lambda r: nativestr(r) == 'OK'
         ),
+        string_keys_to_dict(
+            'SDIFF SINTER SMEMBERS SUNION',
+            lambda r: r and set(r) or set()
+        ),
         string_keys_to_dict(
             'ZRANGE ZRANGEBYSCORE ZREVRANGE ZREVRANGEBYSCORE',
             zset_score_pairs
@@ -403,6 +408,103 @@ class Ledis(object):
         return self.execute_command('LPERSIST', name)
 
 
+    #### SET COMMANDS ####
+    def sadd(self, name, *values):
+        "Add ``value(s)`` to set ``name``"
+        return self.execute_command('SADD', name, *values)
+
+    def scard(self, name):
+        "Return the number of elements in set ``name``"
+        return self.execute_command('SCARD', name)
+
+    def sdiff(self, keys, *args):
+        "Return the difference of sets specified by ``keys``"
+        args = list_or_args(keys, args)
+        return self.execute_command('SDIFF', *args)
+
+    def sdiffstore(self, dest, keys, *args):
+        """
+        Store the difference of sets specified by ``keys`` into a new
+        set named ``dest``.  Returns the number of keys in the new set.
+        """
+        args = list_or_args(keys, args)
+        return self.execute_command('SDIFFSTORE', dest, *args)
+
+    def sinter(self, keys, *args):
+        "Return the intersection of sets specified by ``keys``"
+        args = list_or_args(keys, args)
+        return self.execute_command('SINTER', *args)
+
+    def sinterstore(self, dest, keys, *args):
+        """
+        Store the intersection of sets specified by ``keys`` into a new
+        set named ``dest``.  Returns the number of keys in the new set.
+        """
+        args = list_or_args(keys, args)
+        return self.execute_command('SINTERSTORE', dest, *args)
+
+    def sismember(self, name, value):
+        "Return a boolean indicating if ``value`` is a member of set ``name``"
+        return self.execute_command('SISMEMBER', name, value)
+
+    def smembers(self, name):
+        "Return all members of the set ``name``"
+        return self.execute_command('SMEMBERS', name)
+
+    def srem(self, name, *values):
+        "Remove ``values`` from set ``name``"
+        return self.execute_command('SREM', name, *values)
+
+    def sunion(self, keys, *args):
+        "Return the union of sets specified by ``keys``"
+        args = list_or_args(keys, args)
+        return self.execute_command('SUNION', *args)
+
+    def sunionstore(self, dest, keys, *args):
+        """
+        Store the union of sets specified by ``keys`` into a new
+        set named ``dest``.  Returns the number of keys in the new set.
+        """
+        args = list_or_args(keys, args)
+        return self.execute_command('SUNIONSTORE', dest, *args)
+
+    # SPECIAL COMMANDS SUPPORTED BY LEDISDB
+    def sclear(self, name):
+        "Delete key ``name`` from set"
+        return self.execute_command('SCLEAR', name)
+
+    def smclear(self, *names):
+        "Delete multiple keys ``names`` from set"
+        return self.execute_command('SMCLEAR', *names)
+
+    def sexpire(self, name, time):
+        """
+        Set an expire flag on key name for time milliseconds.
+        time can be represented by an integer or a Python timedelta object.
+        """
+        if isinstance(time, datetime.timedelta):
+            time = time.seconds + time.days * 24 * 3600
+        return self.execute_command('SEXPIRE', name, time)
+
+    def sexpireat(self, name, when):
+        """
+        Set an expire flag on key name. when can be represented as an integer
+        representing  unix time in milliseconds (unix time * 1000) or a
+        Python datetime object.
+        """
+        if isinstance(when, datetime.datetime):
+            when = int(mod_time.mktime(when.timetuple()))
+        return self.execute_command('SEXPIREAT', name, when)
+
+    def sttl(self, name):
+        "Returns the number of seconds until the key name will expire"
+        return self.execute_command('STTL', name)
+
+    def spersist(self, name):
+        "Removes an expiration on name"
+        return self.execute_command('SPERSIST', name)
+
+
     #### SORTED SET COMMANDS ####
     def zadd(self, name, *args, **kwargs):
         """
@@ -693,7 +795,6 @@ class Ledis(object):
         return self.execute_command('HPERSIST', name)
 
 
-
     ### BIT COMMANDS
     def bget(self, name):
         ""
diff --git a/client/ledis-py/tests/test_cmd_bit.py b/client/ledis-py/tests/test_cmd_bit.py
index 7863d21..c1976a7 100644
--- a/client/ledis-py/tests/test_cmd_bit.py
+++ b/client/ledis-py/tests/test_cmd_bit.py
@@ -3,21 +3,15 @@
 
 import unittest
 import sys
-import datetime, time
 sys.path.append('..')
 
 import ledis
 from ledis._compat import b
-from ledis import ResponseError
-
+from util import expire_at, expire_at_seconds
 
 l = ledis.Ledis(port=6380)
 
 
-def current_time():
-    return datetime.datetime.now()
-
-
 class TestCmdBit(unittest.TestCase):
     def setUp(self):
         pass
@@ -94,21 +88,17 @@ class TestCmdBit(unittest.TestCase):
         assert l.bttl('a') == -1
 
     def test_bexpireat_datetime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.bsetbit('a', 1, True)
-        assert l.bexpireat('a', expire_at)
+        assert l.bexpireat('a', expire_at())
         assert 0 < l.bttl('a') <= 61
 
     def test_bexpireat_unixtime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.bsetbit('a', 1, True)
-        expire_at_seconds = int(time.mktime(expire_at.timetuple()))
-        assert l.bexpireat('a', expire_at_seconds)
+        assert l.bexpireat('a', expire_at_seconds())
         assert 0 < l.bttl('a') <= 61
 
     def test_bexpireat_no_key(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
-        assert not l.bexpireat('a', expire_at)
+        assert not l.bexpireat('a', expire_at())
 
     def test_bttl_and_bpersist(self):
         l.bsetbit('a', 1, True)
diff --git a/client/ledis-py/tests/test_cmd_hash.py b/client/ledis-py/tests/test_cmd_hash.py
index d0fe5ab..8a89af2 100644
--- a/client/ledis-py/tests/test_cmd_hash.py
+++ b/client/ledis-py/tests/test_cmd_hash.py
@@ -3,19 +3,16 @@
 
 import unittest
 import sys
-import datetime, time
+
 sys.path.append('..')
 
 import ledis
-from ledis._compat import b, iteritems, itervalues
-from ledis import ResponseError
+from ledis._compat import itervalues
+from util import expire_at, expire_at_seconds
 
 
 l = ledis.Ledis(port=6380)
 
-def current_time():
-    return datetime.datetime.now()
-
 
 class TestCmdHash(unittest.TestCase):
     def setUp(self):
@@ -35,7 +32,7 @@ class TestCmdHash(unittest.TestCase):
         l.hset('myhash', 'field1', 'foo')
         l.hdel('myhash', 'field2')
         assert l.hexists('myhash', 'field1') == 1
-        assert l.hexists('myhash', 'field2') == 0      
+        assert l.hexists('myhash', 'field2') == 0
 
     def test_hget(self):
         l.hset('myhash', 'field1', 'foo')
@@ -110,21 +107,17 @@ class TestCmdHash(unittest.TestCase):
         assert l.httl('myhash') <= 100
 
     def test_hexpireat_datetime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.hset('a', 'f', 'foo')
-        assert l.hexpireat('a', expire_at)
+        assert l.hexpireat('a', expire_at())
         assert 0 < l.httl('a') <= 61
 
     def test_hexpireat_unixtime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.hset('a', 'f', 'foo')
-        expire_at_seconds = int(time.mktime(expire_at.timetuple()))
-        assert l.hexpireat('a', expire_at_seconds)
+        assert l.hexpireat('a', expire_at_seconds())
         assert 0 < l.httl('a') <= 61
 
     def test_hexpireat_no_key(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
-        assert not l.hexpireat('a', expire_at)
+        assert not l.hexpireat('a', expire_at())
 
     def test_hexpireat(self):
         assert l.hexpireat('myhash', 1577808000) == 0
diff --git a/client/ledis-py/tests/test_cmd_kv.py b/client/ledis-py/tests/test_cmd_kv.py
index f5a9de7..774b800 100644
--- a/client/ledis-py/tests/test_cmd_kv.py
+++ b/client/ledis-py/tests/test_cmd_kv.py
@@ -3,19 +3,16 @@
 
 import unittest
 import sys
-import datetime, time
 sys.path.append('..')
 
 import ledis
 from ledis._compat import b, iteritems
+from util import expire_at, expire_at_seconds
+
 
 l = ledis.Ledis(port=6380)
 
 
-def current_time():
-    return datetime.datetime.now()
-
-
 class TestCmdKv(unittest.TestCase):
     def setUp(self):
         pass
@@ -32,10 +29,6 @@ class TestCmdKv(unittest.TestCase):
         assert l.decr('a', amount=5) == -7
         assert l['a'] == b('-7')
 
-        #FIXME: how to test exception?
-        # l.set('b', '234293482390480948029348230948')
-        # self.assertRaises(ResponseError, l.delete('b'))
-
     def test_decrby(self):
         assert l.delete('a') == 1
         assert l.decrby('a') == -1
@@ -134,21 +127,17 @@ class TestCmdKv(unittest.TestCase):
         assert not (l.expire('a', 100))
 
     def test_expireat_datetime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.set('a', '1')
-        assert l.expireat('a', expire_at)
+        assert l.expireat('a', expire_at())
         assert 0 < l.ttl('a') <= 61
 
     def test_expireat_unixtime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.set('a', '1')
-        expire_at_seconds = int(time.mktime(expire_at.timetuple()))
-        assert l.expireat('a', expire_at_seconds)
+        assert l.expireat('a', expire_at_seconds())
         assert 0 < l.ttl('a') <= 61
 
     def test_expireat_no_key(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
-        assert not l.expireat('a', expire_at)
+        assert not l.expireat('a', expire_at())
 
     def test_expireat(self):
         l.set('a', 'hello')
diff --git a/client/ledis-py/tests/test_cmd_list.py b/client/ledis-py/tests/test_cmd_list.py
index c27d673..f87b8a1 100644
--- a/client/ledis-py/tests/test_cmd_list.py
+++ b/client/ledis-py/tests/test_cmd_list.py
@@ -2,20 +2,17 @@
 # Test Cases for list commands
 
 import unittest
-import datetime, time
 import sys
 sys.path.append('..')
 
 import ledis
 from ledis._compat import b
+from util import expire_at, expire_at_seconds
+
 
 l = ledis.Ledis(port=6380)
 
 
-def current_time():
-    return datetime.datetime.now()
-
-
 class TestCmdList(unittest.TestCase):
     def setUp(self):
         pass
@@ -84,21 +81,17 @@ class TestCmdList(unittest.TestCase):
         assert l.lttl('mylist') == -1
 
     def test_lexpireat_datetime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.rpush('mylist', '1')
-        assert l.lexpireat('mylist', expire_at)
+        assert l.lexpireat('mylist', expire_at())
         assert 0 < l.lttl('mylist') <= 61
 
     def test_lexpireat_unixtime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.rpush('mylist', '1')
-        expire_at_seconds = int(time.mktime(expire_at.timetuple()))
-        assert l.lexpireat('mylist', expire_at_seconds)
+        assert l.lexpireat('mylist', expire_at_seconds())
         assert l.lttl('mylist') <= 61
 
     def test_lexpireat_no_key(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
-        assert not l.lexpireat('mylist', expire_at)
+        assert not l.lexpireat('mylist', expire_at())
 
     def test_lttl_and_lpersist(self):
         l.rpush('mylist', '1')
diff --git a/client/ledis-py/tests/test_cmd_set.py b/client/ledis-py/tests/test_cmd_set.py
new file mode 100644
index 0000000..0d2eec9
--- /dev/null
+++ b/client/ledis-py/tests/test_cmd_set.py
@@ -0,0 +1,156 @@
+# coding: utf-8
+# Test set commands
+
+import unittest
+import sys
+sys.path.append('..')
+
+import pytest
+
+import ledis
+from ledis._compat import b
+from ledis import ResponseError
+from util import expire_at, expire_at_seconds
+
+l = ledis.Ledis(port=6380)
+
+
+class TestCmdSet(unittest.TestCase):
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        l.smclear('a', 'b', 'c')
+
+    def test_sadd(self):
+        members = set([b('1'), b('2'), b('3')])
+        l.sadd('a', *members)
+        assert l.smembers('a') == members
+
+    def test_scard(self):
+        l.sadd('a', '1', '2', '3')
+        assert l.scard('a') == 3
+
+    def test_sdiff(self):
+        l.sadd('a', '1', '2', '3')
+        assert l.sdiff('a', 'b') == set([b('1'), b('2'), b('3')])
+        l.sadd('b', '2', '3')
+        assert l.sdiff('a', 'b') == set([b('1')])
+
+    def test_sdiffstore(self):
+        l.sadd('a', '1', '2', '3')
+        assert l.sdiffstore('c', 'a', 'b') == 3
+        assert l.smembers('c') == set([b('1'), b('2'), b('3')])
+        l.sadd('b', '2', '3')
+        print l.smembers('c')
+        print "before"
+        assert l.sdiffstore('c', 'a', 'b') == 1
+        print l.smembers('c')
+        assert l.smembers('c') == set([b('1')])
+
+    def test_sinter(self):
+        l.sadd('a', '1', '2', '3')
+        assert l.sinter('a', 'b') == set()
+        l.sadd('b', '2', '3')
+        assert l.sinter('a', 'b') == set([b('2'), b('3')])
+
+    def test_sinterstore(self):
+        l.sadd('a', '1', '2', '3')
+        assert l.sinterstore('c', 'a', 'b') == 0
+        assert l.smembers('c') == set()
+        l.sadd('b', '2', '3')
+        assert l.sinterstore('c', 'a', 'b') == 2
+        assert l.smembers('c') == set([b('2'), b('3')])
+
+    def test_sismember(self):
+        l.sadd('a', '1', '2', '3')
+        assert l.sismember('a', '1')
+        assert l.sismember('a', '2')
+        assert l.sismember('a', '3')
+        assert not l.sismember('a', '4')
+
+    def test_smembers(self):
+        l.sadd('a', '1', '2', '3')
+        assert l.smembers('a') == set([b('1'), b('2'), b('3')])
+
+    def test_srem(self):
+        l.sadd('a', '1', '2', '3', '4')
+        assert l.srem('a', '5') == 0
+        assert l.srem('a', '2', '4') == 2
+        assert l.smembers('a') == set([b('1'), b('3')])
+
+    def test_sunion(self):
+        l.sadd('a', '1', '2')
+        l.sadd('b', '2', '3')
+        assert l.sunion('a', 'b') == set([b('1'), b('2'), b('3')])
+
+    def test_sunionstore(self):
+        l.sadd('a', '1', '2')
+        l.sadd('b', '2', '3')
+        assert l.sunionstore('c', 'a', 'b') == 3
+        assert l.smembers('c') == set([b('1'), b('2'), b('3')])
+
+    def test_sclear(self):
+        members = set([b('1'), b('2'), b('3')])
+        l.sadd('a', *members)
+        assert l.sclear('a') == 3
+        assert l.sclear('a') == 0
+
+    def test_smclear(self):
+        members = set([b('1'), b('2'), b('3')])
+        l.sadd('a', *members)
+        l.sadd('b', *members)
+        assert l.smclear('a', 'b') == 2
+
+    def test_sexpire(self):
+        members = set([b('1'), b('2'), b('3')])
+        assert l.sexpire('a', 100) == 0
+        l.sadd('a', *members)
+        assert l.sexpire('a', 100) == 1
+        assert l.sttl('a') <= 100
+
+    def test_sexpireat_datetime(self):
+        members = set([b('1'), b('2'), b('3')])
+        l.sadd('a', *members)
+        assert l.sexpireat('a', expire_at())
+        assert 0 < l.sttl('a') <= 61
+
+    def test_sexpireat_unixtime(self):
+        members = set([b('1'), b('2'), b('3')])
+        l.sadd('a', *members)
+        assert l.sexpireat('a', expire_at_seconds())
+        assert 0 < l.sttl('a') <= 61
+
+    def test_sexpireat_no_key(self):
+        assert not l.sexpireat('a', expire_at())
+
+    def test_sexpireat(self):
+        assert l.sexpireat('a', 1577808000) == 0
+        members = set([b('1'), b('2'), b('3')])
+        l.sadd('a', *members)
+        assert l.sexpireat('a', 1577808000) == 1
+
+    def test_sttl(self):
+        members = set([b('1'), b('2'), b('3')])
+        l.sadd('a', *members)
+        assert l.sexpire('a', 100)
+        assert l.sttl('a') <= 100
+
+    def test_spersist(self):
+        members = set([b('1'), b('2'), b('3')])
+        l.sadd('a', *members)
+        l.sexpire('a', 100)
+        assert l.sttl('a') <= 100
+        assert l.spersist('a')
+        assert l.sttl('a') == -1
+
+    def test_invalid_params(self):
+        with pytest.raises(ResponseError) as excinfo:
+            l.sadd("a")
+        assert excinfo.value.message == "invalid command param"
+
+    def test_invalid_value(self):
+        members = set([b('1'), b('2'), b('3')])
+        l.sadd('a', *members)
+        self.assertRaises(ResponseError, lambda: l.sexpire('a', 'a'))
+
diff --git a/client/ledis-py/tests/test_cmd_zset.py b/client/ledis-py/tests/test_cmd_zset.py
index 08d0e8a..08233fc 100644
--- a/client/ledis-py/tests/test_cmd_zset.py
+++ b/client/ledis-py/tests/test_cmd_zset.py
@@ -3,17 +3,14 @@
 
 import unittest
 import sys
-import datetime, time
 sys.path.append('..')
 
 import ledis
-from ledis._compat import b, iteritems
-from ledis import ResponseError
+from ledis._compat import b
+from util import expire_at, expire_at_seconds
 
 l = ledis.Ledis(port=6380)
 
-def current_time():
-    return datetime.datetime.now()
 
 class TestCmdZset(unittest.TestCase):
     def setUp(self):
@@ -62,7 +59,7 @@ class TestCmdZset(unittest.TestCase):
         assert l.zrangebyscore('a', 2, 4, start=1, num=2) == \
             [b('a3'), b('a4')]
 
-        # withscores 
+        # withscores
         assert l.zrangebyscore('a', 2, 4, withscores=True) == \
             [('a2', 2), ('a3', 3), ('a4', 4)]
 
@@ -145,21 +142,17 @@ class TestCmdZset(unittest.TestCase):
         assert l.zttl('a') == -1
 
     def test_zexpireat_datetime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.zadd('a', a1=1)
-        assert l.zexpireat('a', expire_at)
+        assert l.zexpireat('a', expire_at())
         assert 0 < l.zttl('a') <= 61
 
     def test_zexpireat_unixtime(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
         l.zadd('a', a1=1)
-        expire_at_seconds = int(time.mktime(expire_at.timetuple()))
-        assert l.zexpireat('a', expire_at_seconds)
+        assert l.zexpireat('a', expire_at_seconds())
         assert 0 < l.zttl('a') <= 61
 
     def test_zexpireat_no_key(self):
-        expire_at = current_time() + datetime.timedelta(minutes=1)
-        assert not l.zexpireat('a', expire_at)
+        assert not l.zexpireat('a', expire_at())
 
     def test_zttl_and_zpersist(self):
         l.zadd('a', a1=1)
diff --git a/client/ledis-py/tests/util.py b/client/ledis-py/tests/util.py
new file mode 100644
index 0000000..cdbd218
--- /dev/null
+++ b/client/ledis-py/tests/util.py
@@ -0,0 +1,20 @@
+#coding: utf-8
+import datetime
+import time
+
+
+def current_time():
+    return datetime.datetime.now()
+
+
+def expire_at(minute=1):
+    expire_at = current_time() + datetime.timedelta(minutes=minute)
+    return expire_at
+
+
+def expire_at_seconds(minute=1):
+    return int(time.mktime(expire_at(minute=minute).timetuple()))
+
+if __name__ == "__main__":
+    print expire_at()
+    print expire_at_seconds()
\ No newline at end of file
diff --git a/client/nodejs/example.js b/client/nodejs/example.js
index 101a106..54d61df 100644
--- a/client/nodejs/example.js
+++ b/client/nodejs/example.js
@@ -36,16 +36,38 @@ client.bget("bit key 3", function(err, result){
 });
 
 //test zunionstore & zinterstore 
-client.zadd("zset1", 1, "one")
-client.zadd("zset1", 2, "two")
+client.zadd("zset1", 1, "one");
+client.zadd("zset1", 2, "two");
 
-client.zadd("zset2", 1, "one")
-client.zadd("zset2", 2, "two")
-client.zadd("zset2", 3, "three")
+client.zadd("zset2", 1, "one");
+client.zadd("zset2", 2, "two");
+client.zadd("zset2", 3, "three");
+
+client.zunionstore("out", 2, "zset1", "zset2", "weights", 2, 3, ledis.print);
+client.zrange("out", 0, -1, "withscores", ledis.print);
+
+client.zinterstore("out", 2, "zset1", "zset2", "weights", 2, 3, ledis.print);
+client.zrange("out", 0, -1, "withscores", ledis.print);
+
+
+//example of set commands
+client.sadd("a", 1, 2, 3);
+client.sadd("b", 3, 4, 5);
+client.sismember("a", 1, ledis.print);
+client.smembers("a", ledis.print);
+client.sdiff("a", "b", ledis.print);
+client.sdiffstore("c", "a", "b", ledis.print);
+client.sinter("a", "b", ledis.print);
+client.sinterstore("c", "a", "b", ledis.print);
+client.sunion("a", "b", ledis.print);
+client.sunionstore("c", "a", "b", ledis.print);
+client.srem("a", 1, ledis.print);
+client.sclear("c", ledis.print);
+client.smclear("a", "b", ledis.print);
+client.sexpire("a", 100, ledis.print);
+client.sexpireat("a", 1577808000, ledis.print);
+client.sttl("a", ledis.print);
+client.spersist("a", ledis.print);
 
-client.zunionstore("out", 2, "zset1", "zset2", "weights", 2, 3, ledis.print)
-client.zrange("out", 0, -1, "withscores", ledis.print) 
 
-client.zinterstore("out", 2, "zset1", "zset2", "weights", 2, 3, ledis.print)
-client.zrange("out", 0, -1, "withscores", ledis.print) 
 client.quit()
diff --git a/client/nodejs/ledis/lib/commands.js b/client/nodejs/ledis/lib/commands.js
index e814d23..38ce362 100644
--- a/client/nodejs/ledis/lib/commands.js
+++ b/client/nodejs/ledis/lib/commands.js
@@ -2,6 +2,10 @@
 module.exports = [
     "quit",
 
+    "ping",
+    "echo",
+    "select",
+
 	"bget",
 	"bdelete",
 	"bsetbit",
@@ -93,4 +97,26 @@ module.exports = [
 	"zexpireat",
 	"zttl",
 	"zpersist",
+
+
+	"sadd",
+	"scard",
+	"sdiff",
+	"sdiffstore",
+	"sinter",
+	"sinterstore",
+	"sismember",
+	"smembers",
+	"srem",
+	"sunion",
+	"sunionstore",
+
+
+	"sclear",
+	"smclear",
+	"sexpire",
+	"sexpireat",
+	"sttl",
+	"spersist"
+
 ];
diff --git a/client/openresty/ledis.lua b/client/openresty/ledis.lua
index 06d9161..aa2335a 100644
--- a/client/openresty/ledis.lua
+++ b/client/openresty/ledis.lua
@@ -113,6 +113,27 @@ local commands = {
     "bttl",
     "bpersist",
 
+    --[[set]]
+    "sadd",
+    "scard",
+    "sdiff",
+    "sdiffstore",
+    "sinter",
+    "sinterstore",
+    "sismember",
+    "smembers",
+    "srem",
+    "sunion",
+    "sunionstore",
+
+
+    "sclear",
+    "smclear",
+    "sexpire",
+    "sexpireat",
+    "sttl",
+    "spersist",
+
     --[[server]]
     "ping",
     "echo",
diff --git a/ledis/scan_test.go b/ledis/scan_test.go
index 1e14a60..c2dbd34 100644
--- a/ledis/scan_test.go
+++ b/ledis/scan_test.go
@@ -1,8 +1,6 @@
 package ledis
 
 import (
-	"fmt"
-	"github.com/siddontang/ledisdb/store"
 	"testing"
 )
 
@@ -198,26 +196,6 @@ func TestDBBScan(t *testing.T) {
 		t.Fatal(err.Error())
 	}
 
-	ek1 := db.bEncodeMetaKey(k1)
-	fmt.Printf("%x\n", ek1)
-	ek2 := db.bEncodeMetaKey(k2)
-	fmt.Printf("%x\n", ek2)
-	ek3 := db.bEncodeMetaKey(k3)
-	fmt.Printf("%x\n", ek3)
-
-	start := db.bEncodeMetaKey(nil)
-	fmt.Printf("start: %x\n", start)
-	end := db.bEncodeMetaKey(nil)
-	end[len(end)-1] = BitMetaType + 1
-	fmt.Printf("end: %x\n", end)
-
-	it := db.db.RangeLimitIterator(start, end, store.RangeClose, 0, 4)
-
-	for ; it.Valid(); it.Next() {
-		fmt.Printf("%x\n", it.RawKey())
-	}
-	it.Close()
-
 	if v, err := db.BScan(nil, 1, true); err != nil {
 		t.Fatal(err)
 	} else if len(v) != 1 {
diff --git a/ledis/t_set.go b/ledis/t_set.go
index 51458bb..ae58e3a 100644
--- a/ledis/t_set.go
+++ b/ledis/t_set.go
@@ -490,7 +490,6 @@ func (db *DB) sStoreGeneric(dstKey []byte, optType byte, keys ...[]byte) (int64,
 
 	var err error
 	var ek []byte
-	var num int64 = 0
 	var v [][]byte
 
 	switch optType {
@@ -513,22 +512,21 @@ func (db *DB) sStoreGeneric(dstKey []byte, optType byte, keys ...[]byte) (int64,
 
 		ek = db.sEncodeSetKey(dstKey, m)
 
-		if v, err := db.db.Get(ek); err != nil {
+		if _, err := db.db.Get(ek); err != nil {
 			return 0, err
-		} else if v == nil {
-			num++
 		}
 
 		t.Put(ek, nil)
-
 	}
 
-	if _, err = db.sIncrSize(dstKey, num); err != nil {
+	var num = int64(len(v))
+	sk := db.sEncodeSizeKey(dstKey)
+	t.Put(sk, PutInt64(num))
+
+	if err = t.Commit(); err != nil {
 		return 0, err
 	}
-
-	err = t.Commit()
-	return num, err
+	return num, nil
 }
 
 func (db *DB) SClear(key []byte) (int64, error) {
diff --git a/ledis/t_set_test.go b/ledis/t_set_test.go
index c5f6523..110a982 100644
--- a/ledis/t_set_test.go
+++ b/ledis/t_set_test.go
@@ -147,7 +147,7 @@ func testUnion(db *DB, t *testing.T) {
 	m2 := []byte("m2")
 	m3 := []byte("m3")
 	db.SAdd(key, m1, m2)
-	db.SAdd(key1, m1, m3)
+	db.SAdd(key1, m1, m2, m3)
 	db.SAdd(key2, m2, m3)
 	if _, err := db.sUnionGeneric(key, key2); err != nil {
 		t.Fatal(err)
@@ -158,11 +158,13 @@ func testUnion(db *DB, t *testing.T) {
 	}
 
 	dstkey := []byte("union_dsk")
+	db.SAdd(dstkey, []byte("x"))
 	if num, err := db.SUnionStore(dstkey, key1, key2); err != nil {
 		t.Fatal(err)
 	} else if num != 3 {
 		t.Fatal(num)
 	}
+
 	if _, err := db.SMembers(dstkey); err != nil {
 		t.Fatal(err)
 	}
diff --git a/ledis/t_zset.go b/ledis/t_zset.go
index 0431046..202543a 100644
--- a/ledis/t_zset.go
+++ b/ledis/t_zset.go
@@ -848,29 +848,25 @@ func (db *DB) ZUnionStore(destKey []byte, srcKeys [][]byte, weights []int64, agg
 
 	db.zDelete(t, destKey)
 
-	var num int64 = 0
 	for member, score := range destMap {
 		if err := checkZSetKMSize(destKey, []byte(member)); err != nil {
 			return 0, err
 		}
 
-		if n, err := db.zSetItem(t, destKey, score, []byte(member)); err != nil {
+		if _, err := db.zSetItem(t, destKey, score, []byte(member)); err != nil {
 			return 0, err
-		} else if n == 0 {
-			//add new
-			num++
 		}
 	}
 
-	if _, err := db.zIncrSize(t, destKey, num); err != nil {
-		return 0, err
-	}
+	var num = int64(len(destMap))
+	sk := db.zEncodeSizeKey(destKey)
+	t.Put(sk, PutInt64(num))
 
 	//todo add binlog
 	if err := t.Commit(); err != nil {
 		return 0, err
 	}
-	return int64(len(destMap)), nil
+	return num, nil
 }
 
 func (db *DB) ZInterStore(destKey []byte, srcKeys [][]byte, weights []int64, aggregate byte) (int64, error) {
@@ -922,28 +918,23 @@ func (db *DB) ZInterStore(destKey []byte, srcKeys [][]byte, weights []int64, agg
 
 	db.zDelete(t, destKey)
 
-	var num int64 = 0
 	for member, score := range destMap {
 		if err := checkZSetKMSize(destKey, []byte(member)); err != nil {
 			return 0, err
 		}
-
-		if n, err := db.zSetItem(t, destKey, score, []byte(member)); err != nil {
+		if _, err := db.zSetItem(t, destKey, score, []byte(member)); err != nil {
 			return 0, err
-		} else if n == 0 {
-			//add new
-			num++
 		}
 	}
 
-	if _, err := db.zIncrSize(t, destKey, num); err != nil {
-		return 0, err
-	}
+	var num int64 = int64(len(destMap))
+	sk := db.zEncodeSizeKey(destKey)
+	t.Put(sk, PutInt64(num))
 	//todo add binlog
 	if err := t.Commit(); err != nil {
 		return 0, err
 	}
-	return int64(len(destMap)), nil
+	return num, nil
 }
 
 func (db *DB) ZScan(key []byte, count int, inclusive bool) ([][]byte, error) {
diff --git a/ledis/t_zset_test.go b/ledis/t_zset_test.go
index 10782d1..212a02d 100644
--- a/ledis/t_zset_test.go
+++ b/ledis/t_zset_test.go
@@ -253,6 +253,9 @@ func TestZUnionStore(t *testing.T) {
 	weights := []int64{1, 2}
 
 	out := []byte("out")
+
+	db.ZAdd(out, ScorePair{3, []byte("out")})
+
 	n, err := db.ZUnionStore(out, keys, weights, AggregateSum)
 	if err != nil {
 		t.Fatal(err.Error())
@@ -296,6 +299,15 @@ func TestZUnionStore(t *testing.T) {
 	if n != 3 {
 		t.Fatal("invalid value ", v)
 	}
+
+	n, err = db.ZCard(out)
+
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	if n != 3 {
+		t.Fatal("invalid value ", n)
+	}
 }
 
 func TestZInterStore(t *testing.T) {
@@ -314,6 +326,8 @@ func TestZInterStore(t *testing.T) {
 	weights := []int64{2, 3}
 	out := []byte("out")
 
+	db.ZAdd(out, ScorePair{3, []byte("out")})
+
 	n, err := db.ZInterStore(out, keys, weights, AggregateSum)
 	if err != nil {
 		t.Fatal(err.Error())
@@ -329,7 +343,6 @@ func TestZInterStore(t *testing.T) {
 		t.Fatal("invalid value ", v)
 	}
 
-	out = []byte("out")
 	n, err = db.ZInterStore(out, keys, weights, AggregateMin)
 	if err != nil {
 		t.Fatal(err.Error())
@@ -355,4 +368,12 @@ func TestZInterStore(t *testing.T) {
 		t.Fatal("invalid value ", n)
 	}
 
+	n, err = db.ZCard(out)
+
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	if n != 1 {
+		t.Fatal("invalid value ", n)
+	}
 }