diff --git a/common/consumertable.cpp b/common/consumertable.cpp
index c3ed28ab7..5840622a1 100644
--- a/common/consumertable.cpp
+++ b/common/consumertable.cpp
@@ -38,6 +38,7 @@ ConsumerTable::ConsumerTable(DBConnector *db, string tableName) :
         catch (...)
         {
             delete m_subscribe;
+            m_subscribe = NULL;
         }
     }
 
diff --git a/common/scheme.h b/common/scheme.h
index 30fb74de9..68bc8df73 100644
--- a/common/scheme.h
+++ b/common/scheme.h
@@ -1,17 +1,28 @@
 #ifndef __SCHEME__
 #define __SCHEME__
 
+
+#define _in_
+#define _out_
+#define _inout_
+
 namespace swss {
 
 #define APPL_DB         0
 #define ASIC_DB         1
 
-#define APP_PORT_TABLE_NAME     "PORT_TABLE"
-#define APP_VLAN_TABLE_NAME     "VLAN_TABLE"
-#define APP_LAG_TABLE_NAME      "LAG_TABLE"
-#define APP_INTF_TABLE_NAME     "INTF_TABLE"
-#define APP_NEIGH_TABLE_NAME    "NEIGH_TABLE"
-#define APP_ROUTE_TABLE_NAME    "ROUTE_TABLE"
+#define APP_PORT_TABLE_NAME             "PORT_TABLE"
+#define APP_VLAN_TABLE_NAME             "VLAN_TABLE"
+#define APP_LAG_TABLE_NAME              "LAG_TABLE"
+#define APP_INTF_TABLE_NAME             "INTF_TABLE"
+#define APP_NEIGH_TABLE_NAME            "NEIGH_TABLE"
+#define APP_ROUTE_TABLE_NAME            "ROUTE_TABLE"
+#define APP_TC_TO_QUEUE_MAP_TABLE_NAME  "TC_TO_QUEUE_MAP_TABLE"
+#define APP_SCHEDULER_TABLE_NAME        "SCHEDULER_TABLE"
+#define APP_DSCP_TO_TC_MAP_TABLE_NAME   "DSCP_TO_TC_MAP_TABLE"
+#define APP_QUEUE_TABLE_NAME            "QUEUE_TABLE"
+#define APP_PORT_QOS_MAP_TABLE_NAME     "PORT_QOS_MAP_TABLE"
+#define APP_WRED_PROFILE_TABLE_NAME     "WRED_PROFILE_TABLE"
 
 #define IPV4_NAME "IPv4"
 #define IPV6_NAME "IPv6"
diff --git a/common/select.cpp b/common/select.cpp
index 0c4312308..580c0a306 100644
--- a/common/select.cpp
+++ b/common/select.cpp
@@ -1,4 +1,6 @@
+#include <algorithm>
 #include "common/selectable.h"
+#include "common/logger.h"
 #include "common/select.h"
 #include <stdio.h>
 #include <sys/time.h>
@@ -8,9 +10,20 @@ using namespace std;
 
 namespace swss {
 
-void Select::addSelectable(Selectable *c)
+void Select::addSelectable(_in_ Selectable *selectable)
 {
-    m_objects.push_back(c);
+    if(std::find(m_objects.begin(), m_objects.end(), selectable) != m_objects.end()) {
+        SWSS_LOG_WARN("Selectable:%p already been added to the list, ignoring\n.");
+        return;
+    }
+    m_objects.push_back(selectable);
+}
+    
+void Select::addSelectables(_in_ std::vector<Selectable *> &selectables)
+{
+    for(auto it : selectables) {
+        addSelectable(it);
+    }    
 }
 
 void Select::addFd(int fd)
@@ -18,7 +31,7 @@ void Select::addFd(int fd)
     m_fds.push_back(fd);
 }
 
-int Select::select(Selectable **c, int *fd, unsigned int timeout)
+int Select::select(_out_ Selectable **c, _out_ int *fd, _in_ unsigned int timeout)
 {
     struct timeval t = {0, (suseconds_t)(timeout)*1000};
     struct timeval *pTimeout = NULL;
diff --git a/common/select.h b/common/select.h
index 76617cbec..0c8158055 100644
--- a/common/select.h
+++ b/common/select.h
@@ -13,7 +13,8 @@ class Select
 {
 public:
     /* Add object for select */
-    void addSelectable(Selectable *c);
+    void addSelectables(_in_ std::vector<Selectable *> &selectables);
+    void addSelectable(_in_ Selectable *selectable);
 
     /* Add file-descriptor for select  */
     void addFd(int fd);
@@ -28,8 +29,7 @@ class Select
         ERROR = 2,
         TIMEOUT = 3
     };
-    int select(Selectable **c, int *fd,
-               unsigned int timeout = std::numeric_limits<unsigned int>::max());
+    int select(_out_ Selectable **c, _out_ int *fd, _in_ unsigned int timeout = std::numeric_limits<unsigned int>::max());
 
 private:
     /* Create a new redisContext, SELECT DB and SUBSRIBE */
diff --git a/common/table.cpp b/common/table.cpp
index 1fccae179..4d32b7cc8 100644
--- a/common/table.cpp
+++ b/common/table.cpp
@@ -15,6 +15,11 @@ Table::Table(DBConnector *db, string tableName) :
 {
 }
 
+std::string Table::getTableName()const
+{
+    return m_tableName;
+}
+
 string Table::getKeyName(string key)
 {
     return m_tableName + ':' + key;
diff --git a/common/table.h b/common/table.h
index d079341ff..2816e9663 100644
--- a/common/table.h
+++ b/common/table.h
@@ -38,11 +38,11 @@ class Table {
     void delField(std::string key, std::string field);
 
     virtual ~Table();
+    std::string getTableName()const;
 
 protected:
     /* Return the actual key name as a comibation of tableName:key */
     std::string getKeyName(std::string key);
-
     std::string getKeyQueueTableName();
     std::string getValueQueueTableName();
     std::string getOpQueueTableName();