gistfile1.txt

git diff rediscluster/client.py
diff --git a/rediscluster/client.py b/rediscluster/client.py
index 7405dad..aeee4a8 100644
--- a/rediscluster/client.py
+++ b/rediscluster/client.py
@@ -60,6 +60,28 @@ class RedisCluster(StrictRedis):
     """
     RedisClusterRequestTTL = 16
 
+
+    # multi-key commands that prevent parallel execution.
+    # have to fall back to serial execution.
+    _rewritten_commands = [
+        'mget',
+        'mset',
+        'msetnx',
+        # 'rename',
+        # 'renamenx',
+        # 'brpoplpush',
+        # 'rpoplpush',
+        # 'sort',
+        # 'sdiff',
+        # 'sdiffstore',
+        # 'sinter',
+        # 'sinterstore',
+        # 'smove',
+        # 'sunion',
+        # 'sunionstore',
+        # 'pfmerge',
+    ]
+
     NODES_CALLBACKS = dict_merge(
         string_keys_to_dict([
             "CLIENT SETNAME", "SENTINEL GET-MASTER-ADDR-BY-NAME", 'SENTINEL MASTER', 'SENTINEL MASTERS',
@@ -238,6 +260,11 @@ class RedisCluster(StrictRedis):
         """
         Send a command to a node in the cluster
         """
+        command = args[0].lower()
+        if command in self._rewritten_commands:
+            cmd = getattr(self, '_rewrite_'+ command)
+            return cmd(*args[1:], **kwargs)
+
         if self.refresh_table_asap:
             self.initialize_slots_cache()
 
@@ -317,7 +344,13 @@ class RedisCluster(StrictRedis):
                 for item in data:
                     yield item
 
-    def mget(self, keys, *args):
+
+    @staticmethod
+    def _get_pairs(l):
+            for i in xrange(0, len(l), 2):
+                yield l[i:i+2]
+
+    def _rewrite_mget(self, *keys):
         """
         Returns a list of values ordered identically to ``keys``
 
@@ -325,24 +358,20 @@ class RedisCluster(StrictRedis):
                       This will go alot slower than a normal mget call in StrictRedis.
                       This method is no longer atomic.
         """
-        return [self.get(arg) for arg in list_or_args(keys, args)]
+        return [self.get(k) for k in keys]
 
-    def mset(self, *args, **kwargs):
+    def _rewrite_mset(self, *args):
         """
         Sets key/values based on a mapping. Mapping can be supplied as a single
         dictionary argument or as kwargs.
 
         Cluster impl: Itterate over all items and do SET on each (k,v) pair
         """
-        if args:
-            if len(args) != 1 or not isinstance(args[0], dict):
-                raise RedisError('MSET requires **kwargs or a single dict arg')
-            kwargs.update(args[0])
-        for pair in iteritems(kwargs):
+        for pair in self._get_pairs(args):
             self.set(pair[0], pair[1])
         return True
 
-    def msetnx(self, *args, **kwargs):
+    def _rewrite_msetnx(self, *args):
         """
         Sets key/values based on a mapping if none of the keys are already set.
         Mapping can be supplied as a single dictionary argument or as kwargs.
@@ -351,17 +380,12 @@ class RedisCluster(StrictRedis):
         Clutser impl: Itterate over all items and do GET to determine if all keys do not exists.
                       If true then call mset() on all keys.
         """
-        if args:
-            if len(args) != 1 or not isinstance(args[0], dict):
-                raise RedisError('MSETNX requires **kwargs or a single dict arg')
-            kwargs.update(args[0])
-
-        # Itterate over all items and fail fast if one value is True.
-        for k, v in kwargs.items():
+        keys = [pair[0] for pair in self._get_pairs(args)]
+        for k in keys:
             if self.get(k):
                 return False
 
-        return self.mset(**kwargs)
+        return self._rewrite_mset(*args)
 
     def rename(self, src, dst):
         """