diff --git a/lualib/mongo.lua b/lualib/mongo.lua
index f9eece35..9760a545 100644
--- a/lualib/mongo.lua
+++ b/lualib/mongo.lua
@@ -84,6 +84,7 @@ local function mongo_auth(mongoc)
 	end
 	return function()
 		assert(mongoc:auth(user, pass))
+		-- todo : If mongoc want to connect to replica set, runCommand ismater here, and call mongoc.__sock:changehost
 	end
 end
 
diff --git a/lualib/socketchannel.lua b/lualib/socketchannel.lua
index e6a061f0..e30114d3 100644
--- a/lualib/socketchannel.lua
+++ b/lualib/socketchannel.lua
@@ -175,11 +175,11 @@ local function connect_once(self)
 	end
 
 	self.__authcoroutine = false
-	return true
+	return self.__sock ~= nil
 end
 
 local function try_connect(self , once)
-	local t = 100
+	local t = 0
 	while not self.__closed do
 		if connect_once(self) then
 			if not once then
@@ -292,6 +292,16 @@ function channel:close()
 	end
 end
 
+function channel:changehost(host, port)
+	self.__host = host
+	if port then
+		self.__port = port
+	end
+	if not self.__closed then
+		close_channel_socket(self)
+	end
+end
+
 channel_meta.__gc = channel.close
 
 local function wrapper_socket_function(f)