From 5eab69a4aae3a90a55ae88c51958e57920931b33 Mon Sep 17 00:00:00 2001
From: SuvarnaMeenakshi <sumeenak@microsoft.com>
Date: Mon, 15 Jun 2020 21:07:58 -0700
Subject: [PATCH 1/8] Fix errors introduced. Add namespace test case for fdb
 related MIB.

Signed-off-by: SuvarnaMeenakshi <sumeenak@microsoft.com>
---
 src/sonic_ax_impl/mibs/__init__.py     |   2 +-
 src/sonic_ax_impl/mibs/ieee802_1ab.py  |  14 +--
 src/sonic_ax_impl/mibs/ietf/rfc2737.py |  16 +--
 tests/mock_tables/asic0/asic_db.json   |  25 ++++
 tests/mock_tables/asic1/asic_db.json   |   9 ++
 tests/namespace/test_fdb.py            | 156 +++++++++++++++++++++++++
 6 files changed, 206 insertions(+), 16 deletions(-)
 create mode 100644 tests/namespace/test_fdb.py

diff --git a/src/sonic_ax_impl/mibs/__init__.py b/src/sonic_ax_impl/mibs/__init__.py
index c9154c7f7..6e9839335 100644
--- a/src/sonic_ax_impl/mibs/__init__.py
+++ b/src/sonic_ax_impl/mibs/__init__.py
@@ -587,6 +587,6 @@ def dbs_get_bridge_port_map(dbs, db_name):
     def dbs_get_vlan_id_from_bvid(dbs, bvid):
         for db_conn in Namespace.get_non_host_dbs(dbs):
             db_conn.connect('ASIC_DB')
-            vlan_obj = db.keys('ASIC_DB', "ASIC_STATE:SAI_OBJECT_TYPE_VLAN:" + bvid)
+            vlan_obj = db_conn.keys('ASIC_DB', "ASIC_STATE:SAI_OBJECT_TYPE_VLAN:" + bvid)
             if vlan_obj is not None:
                 return port_util.get_vlan_id_from_bvid(db_conn, bvid)
diff --git a/src/sonic_ax_impl/mibs/ieee802_1ab.py b/src/sonic_ax_impl/mibs/ieee802_1ab.py
index fa4d2b7e2..4ddd93e4b 100644
--- a/src/sonic_ax_impl/mibs/ieee802_1ab.py
+++ b/src/sonic_ax_impl/mibs/ieee802_1ab.py
@@ -222,18 +222,18 @@ def get_next(self, sub_id):
             return None
         return self.if_range[right]
 
-    def _update_per_namespace_data(self, db_conn, pubsub):
+    def _update_per_namespace_data(self, inst):
         """
         Listen to updates in APP DB, update local cache
         """
-        if not pubsub:
-            redis_client = db_conn.get_redis_client(db_conn.APPL_DB)
-            db = db_conn.get_dbid(db_conn.APPL_DB)
-            pubsub = redis_client.pubsub()
+        if not self.pubsub[inst]:
+            redis_client = self.db_conn[inst].get_redis_client(self.db_conn[inst].APPL_DB)
+            db = self.db_conn[inst].get_dbid(self.db_conn[inst].APPL_DB)
+            self.pubsub[inst] = redis_client.pubsub()
             pubsub.psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
 
         while True:
-            data, interface, if_id = poll_lldp_entry_updates(pubsub)
+            data, interface, if_id = poll_lldp_entry_updates(self.pubsub[inst])
 
             if not data:
                 break
@@ -243,7 +243,7 @@ def _update_per_namespace_data(self, db_conn, pubsub):
 
     def update_data(self):
         for i in range(len(self.db_conn)):
-            self._update_per_namespace_data(self.db_conn[i], self.pubsub[i])
+            self._update_per_namespace_data(i)
 
     def local_port_num(self, sub_id):
         if len(sub_id) == 0:
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc2737.py b/src/sonic_ax_impl/mibs/ietf/rfc2737.py
index a0134cf99..4f5a7eb74 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc2737.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc2737.py
@@ -181,7 +181,7 @@ def reinit_data(self):
             interface = transceiver_entry.split(mibs.TABLE_NAME_SEPARATOR_VBAR)[-1]
             self._update_transceiver_cache(interface)
 
-    def _update_per_namespace_data(self, statedb, pubsub):
+    def _update_per_namespace_data(self, inst):
         """
         Update cache.
         Here we listen to changes in STATE_DB TRANSCEIVER_INFO table
@@ -190,14 +190,14 @@ def _update_per_namespace_data(self, statedb, pubsub):
 
         # This code is not executed in unit test, since mockredis
         # does not support pubsub
-        if not pubsub:
-            redis_client = statedb.get_redis_client(statedb.STATE_DB)
-            db = statedb.get_dbid(statedb.STATE_DB)
-            pubsub = redis_client.pubsub()
-            pubsub.psubscribe("__keyspace@{}__:{}".format(db, self.TRANSCEIVER_KEY_PATTERN))
+        if not self.pubsub[inst]:
+            redis_client = self.statedb[inst].get_redis_client(self.statedb[inst].STATE_DB)
+            db = self.statedb[inst].get_dbid(self.statedb[inst].STATE_DB)
+            self.pubsub[inst] = redis_client.pubsub()
+            self.pubsub[inst].psubscribe("__keyspace@{}__:{}".format(db, self.TRANSCEIVER_KEY_PATTERN))
 
         while True:
-            msg = pubsub.get_message()
+            msg = self.pubsub[inst].get_message()
 
             if not msg:
                 break
@@ -234,7 +234,7 @@ def _update_per_namespace_data(self, statedb, pubsub):
 
     def update_data(self):
         for i in range(len(self.statedb)):
-             self._update_per_namespace_data(self.statedb[i], self.pubsub[i])
+             self._update_per_namespace_data(i)
 
     def _update_transceiver_cache(self, interface):
         """
diff --git a/tests/mock_tables/asic0/asic_db.json b/tests/mock_tables/asic0/asic_db.json
index 2c63c0851..590918051 100644
--- a/tests/mock_tables/asic0/asic_db.json
+++ b/tests/mock_tables/asic0/asic_db.json
@@ -1,2 +1,27 @@
 {
+  "ASIC_STATE:SAI_OBJECT_TYPE_FDB_ENTRY:{\"bridge_id\":\"oid:0x0\",\"bridge_type\":\"SAI_FDB_ENTRY_BRIDGE_TYPE_1Q\",\"mac\":\"7C:FE:90:80:9F:04\",\"switch_id\":\"oid:0x21000000000000\",\"vlan\":\"1000\"}": {
+    "SAI_FDB_ENTRY_ATTR_BRIDGE_PORT_ID": "oid:0x3a000000000608",
+    "SAI_FDB_ENTRY_ATTR_TYPE": "SAI_FDB_ENTRY_TYPE_DYNAMIC"
+  },
+  "ASIC_STATE:SAI_OBJECT_TYPE_FDB_ENTRY:{\"bridge_id\":\"oid:0x0\",\"bridge_type\":\"SAI_FDB_ENTRY_BRIDGE_TYPE_1Q\",\"mac\":\"7C:FE:90:80:9F:06\",\"switch_id\":\"oid:0x21000000000000\",\"vlan\":\"1000\"}": {
+    "SAI_FDB_ENTRY_ATTR_BRIDGE_PORT_ID": "oid:0x3a000000000616",
+    "SAI_FDB_ENTRY_ATTR_TYPE": "SAI_FDB_ENTRY_TYPE_DYNAMIC"
+  },
+  "ASIC_STATE:SAI_OBJECT_TYPE_FDB_ENTRY:{\"bvid\":\"oid:0x26000000000016\",\"mac\":\"7C:FE:90:80:9F:08\",\"switch_id\":\"oid:0x21000000000000\"}": {
+    "SAI_FDB_ENTRY_ATTR_BRIDGE_PORT_ID": "oid:0x3a000000000620",
+    "SAI_FDB_ENTRY_ATTR_TYPE": "SAI_FDB_ENTRY_TYPE_DYNAMIC"
+  },
+  "ASIC_STATE:SAI_OBJECT_TYPE_VLAN:oid:0x26000000000016": {
+    "SAI_VLAN_ATTR_VLAN_ID": "1000"
+  },
+  "ASIC_STATE:SAI_OBJECT_TYPE_BRIDGE_PORT:oid:0x3a000000000608": {
+    "SAI_BRIDGE_PORT_ATTR_TYPE": "SAI_BRIDGE_PORT_TYPE_PORT",
+    "SAI_BRIDGE_PORT_ATTR_PORT_ID": "oid:0x1000000000003",
+    "SAI_BRIDGE_PORT_ATTR_ADMIN_STATE": "true"
+  },
+  "ASIC_STATE:SAI_OBJECT_TYPE_BRIDGE_PORT:oid:0x3a000000000616": {
+    "SAI_BRIDGE_PORT_ATTR_TYPE": "SAI_BRIDGE_PORT_TYPE_PORT",
+    "SAI_BRIDGE_PORT_ATTR_PORT_ID": "oid:0x1000000000005",
+    "SAI_BRIDGE_PORT_ATTR_ADMIN_STATE": "true"
+  }
 }
diff --git a/tests/mock_tables/asic1/asic_db.json b/tests/mock_tables/asic1/asic_db.json
index 2c63c0851..70dedc520 100644
--- a/tests/mock_tables/asic1/asic_db.json
+++ b/tests/mock_tables/asic1/asic_db.json
@@ -1,2 +1,11 @@
 {
+  "ASIC_STATE:SAI_OBJECT_TYPE_FDB_ENTRY:{\"bridge_id\":\"oid:0x0\",\"bridge_type\":\"SAI_FDB_ENTRY_BRIDGE_TYPE_1Q\",\"mac\":\"7C:FE:90:80:9F:10\",\"switch_id\":\"oid:0x21000000000000\",\"vlan\":\"1000\"}": {
+    "SAI_FDB_ENTRY_ATTR_BRIDGE_PORT_ID": "oid:0x3a0000000006208",
+    "SAI_FDB_ENTRY_ATTR_TYPE": "SAI_FDB_ENTRY_TYPE_DYNAMIC"
+  },
+  "ASIC_STATE:SAI_OBJECT_TYPE_BRIDGE_PORT:oid:0x3a000000000620": {
+    "SAI_BRIDGE_PORT_ATTR_TYPE": "SAI_BRIDGE_PORT_TYPE_PORT",
+    "SAI_BRIDGE_PORT_ATTR_PORT_ID": "oid:0x1000000000010",
+    "SAI_BRIDGE_PORT_ATTR_ADMIN_STATE": "true"
+  }
 }
diff --git a/tests/namespace/test_fdb.py b/tests/namespace/test_fdb.py
new file mode 100644
index 000000000..ee95bd5c4
--- /dev/null
+++ b/tests/namespace/test_fdb.py
@@ -0,0 +1,156 @@
+import os
+import sys
+import importlib
+
+modules_path = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+sys.path.insert(0, os.path.join(modules_path, 'src'))
+
+from unittest import TestCase
+
+# noinspection PyUnresolvedReferences
+import tests.mock_tables.dbconnector
+
+from ax_interface.mib import MIBTable
+from ax_interface.pdu import PDUHeader
+from ax_interface.pdu_implementations import GetPDU, GetNextPDU
+from ax_interface import ValueType
+from ax_interface.encodings import ObjectIdentifier
+from ax_interface.constants import PduTypes
+from sonic_ax_impl.mibs.ietf import rfc4363
+from sonic_ax_impl.main import SonicMIB
+import sonic_ax_impl
+
+class TestSonicMIB(TestCase):
+    @classmethod
+    def setUpClass(cls):
+        tests.mock_tables.dbconnector.load_namespace_config()
+        importlib.reload(rfc4363)
+
+        cls.lut = MIBTable(rfc4363.QBridgeMIBObjects)
+        for updater in cls.lut.updater_instances:
+           updater.update_data()
+           updater.reinit_data()
+           updater.update_data()
+
+    def test_getpdu(self):
+        oid = ObjectIdentifier(20, 0, 0, 0, (1, 3, 6, 1, 2, 1, 17, 7, 1, 2, 2, 1, 2, 1000, 124, 254, 144, 128, 159, 4))
+        get_pdu = GetPDU(
+            header=PDUHeader(1, PduTypes.GET, 16, 0, 42, 0, 0, 0),
+            oids=[oid]
+        )
+
+        encoded = get_pdu.encode()
+        response = get_pdu.make_response(self.lut)
+        print(response)
+
+        value0 = response.values[0]
+        self.assertEqual(value0.type_, ValueType.INTEGER)
+        self.assertEqual(str(value0.name), str(oid))
+        self.assertEqual(value0.data, 1)
+
+    def test_getnextpdu(self):
+        get_pdu = GetNextPDU(
+            header=PDUHeader(1, PduTypes.GET, 16, 0, 42, 0, 0, 0),
+            oids=(
+                ObjectIdentifier(20, 0, 0, 0, (1, 3, 6, 1, 2, 1, 17, 7, 1, 2, 2, 1, 2)),
+            )
+        )
+
+        encoded = get_pdu.encode()
+        response = get_pdu.make_response(self.lut)
+        print(response)
+
+        n = len(response.values)
+        value0 = response.values[0]
+        self.assertEqual(value0.type_, ValueType.INTEGER)
+        self.assertEqual(value0.data, 1)
+
+    def test_getnextpdu_exactmatch(self):
+        # oid.include = 1
+        oid = ObjectIdentifier(20, 0, 1, 0, (1, 3, 6, 1, 2, 1, 17, 7, 1, 2, 2, 1, 2, 1000, 124, 254, 144, 128, 159, 4))
+        get_pdu = GetNextPDU(
+            header=PDUHeader(1, PduTypes.GET, 16, 0, 42, 0, 0, 0),
+            oids=[oid]
+        )
+
+        encoded = get_pdu.encode()
+        response = get_pdu.make_response(self.lut)
+        print(response)
+
+        n = len(response.values)
+        value0 = response.values[0]
+        self.assertEqual(value0.type_, ValueType.INTEGER)
+        print("test_getnextpdu_exactmatch: ", str(oid))
+        self.assertEqual(str(value0.name), str(oid))
+        self.assertEqual(value0.data, 1)
+
+    def test_getnextpdu_exactmatch_asic0(self):
+        # oid.include = 1
+        oid = ObjectIdentifier(20, 0, 1, 0, (1, 3, 6, 1, 2, 1, 17, 7, 1, 2, 2, 1, 2, 1000, 124, 254, 144, 128, 159, 6))
+        get_pdu = GetNextPDU(
+            header=PDUHeader(1, PduTypes.GET, 16, 0, 42, 0, 0, 0),
+            oids=[oid]
+        )
+
+        encoded = get_pdu.encode()
+        response = get_pdu.make_response(self.lut)
+        print(response)
+
+        n = len(response.values)
+        value0 = response.values[0]
+        self.assertEqual(value0.type_, ValueType.INTEGER)
+        print("test_getnextpdu_exactmatch: ", str(oid))
+        self.assertEqual(str(value0.name), str(oid))
+        self.assertEqual(value0.data, 9000)
+
+    def test_getnextpdu_exactmatch_asic1(self):
+        # oid.include = 1
+        oid = ObjectIdentifier(20, 0, 1, 0, (1, 3, 6, 1, 2, 1, 17, 7, 1, 2, 2, 1, 2, 1000, 124, 254, 144, 128, 159, 8))
+        get_pdu = GetNextPDU(
+            header=PDUHeader(1, PduTypes.GET, 16, 0, 42, 0, 0, 0),
+            oids=[oid]
+        )
+
+        encoded = get_pdu.encode()
+        response = get_pdu.make_response(self.lut)
+        print(response)
+
+        n = len(response.values)
+        value0 = response.values[0]
+        self.assertEqual(value0.type_, ValueType.INTEGER)
+        print("test_getnextpdu_exactmatch: ", str(oid))
+        self.assertEqual(str(value0.name), str(oid))
+        self.assertEqual(value0.data, 9008)
+
+    def test_getpdu_noinstance(self):
+        get_pdu = GetPDU(
+            header=PDUHeader(1, PduTypes.GET, 16, 0, 42, 0, 0, 0),
+            oids=(
+                ObjectIdentifier(20, 0, 0, 0, (1, 3, 6, 1, 2, 1, 17, 7, 1, 2, 2, 1, 2, 1000, 100001)),
+            )
+        )
+
+        encoded = get_pdu.encode()
+        response = get_pdu.make_response(self.lut)
+        print(response)
+
+        n = len(response.values)
+        value0 = response.values[0]
+        self.assertEqual(value0.type_, ValueType.NO_SUCH_INSTANCE)
+
+    def test_getnextpdu_empty(self):
+        get_pdu = GetNextPDU(
+            header=PDUHeader(1, PduTypes.GET, 16, 0, 42, 0, 0, 0),
+            oids=(
+                ObjectIdentifier(20, 0, 0, 0, (1, 3, 6, 1, 2, 1, 17, 7, 1, 2, 2, 1, 3)),
+            )
+        )
+
+        encoded = get_pdu.encode()
+        response = get_pdu.make_response(self.lut)
+        print(response)
+
+        n = len(response.values)
+        value0 = response.values[0]
+        self.assertEqual(value0.type_, ValueType.END_OF_MIB_VIEW)
+

From 1dced6e497b95a8bde631346a682961ef8a9b862 Mon Sep 17 00:00:00 2001
From: SuvarnaMeenakshi <sumeenak@microsoft.com>
Date: Tue, 16 Jun 2020 10:51:16 -0700
Subject: [PATCH 2/8] Make sure that db connections are done in MIB class init
 functions. Multiple connect is causing an increase in run time causing agentx
 connection to close.

Signed-off-by: SuvarnaMeenakshi <sumeenak@microsoft.com>
---
 src/sonic_ax_impl/mibs/__init__.py            | 22 ++---------------
 src/sonic_ax_impl/mibs/ieee802_1ab.py         | 24 ++++++++++++-------
 src/sonic_ax_impl/mibs/ietf/rfc1213.py        |  7 +++++-
 src/sonic_ax_impl/mibs/ietf/rfc2737.py        |  4 +++-
 src/sonic_ax_impl/mibs/ietf/rfc2863.py        |  3 +++
 src/sonic_ax_impl/mibs/ietf/rfc4292.py        |  1 +
 src/sonic_ax_impl/mibs/ietf/rfc4363.py        |  3 +++
 .../mibs/vendor/cisco/ciscoPfcExtMIB.py       |  2 ++
 .../mibs/vendor/cisco/ciscoSwitchQosMIB.py    |  2 ++
 tests/namespace/test_mibs.py                  |  2 ++
 tests/test_mibs.py                            |  2 ++
 11 files changed, 42 insertions(+), 30 deletions(-)

diff --git a/src/sonic_ax_impl/mibs/__init__.py b/src/sonic_ax_impl/mibs/__init__.py
index 6e9839335..788f54079 100644
--- a/src/sonic_ax_impl/mibs/__init__.py
+++ b/src/sonic_ax_impl/mibs/__init__.py
@@ -160,10 +160,6 @@ def init_mgmt_interface_tables(db_conn):
     :param db_conn: db connector
     :return: tuple of mgmt name to oid map and mgmt name to alias map
     """
-
-    db_conn.connect(CONFIG_DB)
-    db_conn.connect(STATE_DB)
-
     mgmt_ports_keys = db_conn.keys(CONFIG_DB, mgmt_if_entry_table(b'*'))
 
     if not mgmt_ports_keys:
@@ -190,9 +186,6 @@ def init_sync_d_interface_tables(db_conn):
     :return: tuple(if_name_map, if_id_map, oid_map, if_alias_map)
     """
 
-    # Make sure we're connected to COUNTERS_DB
-    db_conn.connect(COUNTERS_DB)
-
     # { if_name (SONiC) -> sai_id }
     # ex: { "Ethernet76" : "1000000000023" }
     if_name_map, if_id_map = port_util.get_interface_oid_map(db_conn)
@@ -232,8 +225,6 @@ def init_sync_d_interface_tables(db_conn):
                        .format(port_util.SONIC_ETHERNET_RE_PATTERN))
         logger.warning("Port name map:\n" + pprint.pformat(if_name_map, indent=2))
 
-    db_conn.connect(APPL_DB)
-
     if_alias_map = dict()
 
     for if_name in if_name_map:
@@ -259,8 +250,6 @@ def init_sync_d_lag_tables(db_conn):
     # { OID -> lag_name (SONiC) }
     oid_lag_name_map = {}
 
-    db_conn.connect(APPL_DB)
-
     lag_entries = db_conn.keys(APPL_DB, b"LAG_TABLE:*")
 
     if not lag_entries:
@@ -293,10 +282,6 @@ def init_sync_d_queue_tables(db_conn):
     Initializes queue maps for SyncD-connected MIB(s).
     :return: tuple(port_queues_map, queue_stat_map)
     """
-
-    # Make sure we're connected to COUNTERS_DB
-    db_conn.connect(COUNTERS_DB)
-
     # { Port index : Queue index (SONiC) -> sai_id }
     # ex: { "1:2" : "1000000000023" }
     queue_name_map = db_conn.get_all(COUNTERS_DB, COUNTERS_QUEUE_NAME_MAP, blocking=True)
@@ -349,7 +334,6 @@ def get_device_metadata(db_conn):
     """
 
     DEVICE_METADATA = "DEVICE_METADATA|localhost"
-    db_conn.connect(db_conn.STATE_DB)
 
     device_metadata = db_conn.get_all(db_conn.STATE_DB, DEVICE_METADATA)
     return device_metadata
@@ -393,7 +377,8 @@ class RedisOidTreeUpdater(MIBUpdater):
     def __init__(self, prefix_str):
         super().__init__()
 
-        self.db_conn = Namespace.init_namespace_dbs() 
+        self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, SNMP_OVERLAY_DB)
         if prefix_str.startswith('.'):
             prefix_str = prefix_str[1:]
         self.prefix_str = prefix_str
@@ -464,7 +449,6 @@ def dbs_keys(dbs, db_name, pattern='*'):
         """
         result_keys=[]
         for db_conn in dbs:
-            db_conn.connect(db_name)
             keys = db_conn.keys(db_name, pattern)
             if keys is not None:
                 result_keys.extend(keys)
@@ -477,7 +461,6 @@ def dbs_get_all(dbs, db_name, _hash, *args, **kwargs):
         """
         result = {}
         for db_conn in dbs:
-            db_conn.connect(db_name)
             if(db_conn.exists(db_name, _hash)):
                 ns_result = db_conn.get_all(db_name, _hash, *args, **kwargs)
                 if ns_result is not None:
@@ -586,7 +569,6 @@ def dbs_get_bridge_port_map(dbs, db_name):
     @staticmethod
     def dbs_get_vlan_id_from_bvid(dbs, bvid):
         for db_conn in Namespace.get_non_host_dbs(dbs):
-            db_conn.connect('ASIC_DB')
             vlan_obj = db_conn.keys('ASIC_DB', "ASIC_STATE:SAI_OBJECT_TYPE_VLAN:" + bvid)
             if vlan_obj is not None:
                 return port_util.get_vlan_id_from_bvid(db_conn, bvid)
diff --git a/src/sonic_ax_impl/mibs/ieee802_1ab.py b/src/sonic_ax_impl/mibs/ieee802_1ab.py
index 4ddd93e4b..dd92fc717 100644
--- a/src/sonic_ax_impl/mibs/ieee802_1ab.py
+++ b/src/sonic_ax_impl/mibs/ieee802_1ab.py
@@ -104,6 +104,7 @@ def __init__(self):
         super().__init__()
 
         self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
         self.loc_chassis_data = {}
 
     def reinit_data(self):
@@ -143,6 +144,8 @@ def __init__(self):
         self.db_conn = Namespace.init_namespace_dbs()
         # establish connection to application database.
         Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
         self.if_name_map = {}
         self.if_alias_map = {}
         self.if_id_map = {}
@@ -383,6 +386,9 @@ def __init__(self):
         super().__init__()
 
         self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
         self.if_name_map = {}
         self.if_alias_map = {}
         self.if_id_map = {}
@@ -491,6 +497,8 @@ def __init__(self):
         self.db_conn = Namespace.init_namespace_dbs() 
         # establish connection to application database.
         Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
         self.if_range = []
         self.mgmt_ips = {}
         self.oid_name_map = {}
@@ -536,18 +544,18 @@ def update_rem_if_mgmt(self, if_oid, if_name):
             return
         self.if_range.sort()
 
-    def _update_per_namespace_data(self, db_conn, pubsub):
+    def _update_per_namespace_data(self, inst):
         """
         Listen to updates in APP DB, update local cache
         """
-        if not pubsub:
-            redis_client = db_conn.get_redis_client(db_conn.APPL_DB)
-            db = db_conn.get_dbid(db_conn.APPL_DB)
-            pubsub = redis_client.pubsub()
-            pubsub.psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
+        if not self.pubsub[inst]:
+            redis_client = self.db_conn[inst].get_redis_client(self.db_conn[inst].APPL_DB)
+            db = self.db_conn[inst].get_dbid(self.db_conn[inst].APPL_DB)
+            self.pubsub[inst] = redis_client.pubsub()
+            self.pubsub[inst].psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
 
         while True:
-            data, interface, if_index = poll_lldp_entry_updates(pubsub)
+            data, interface, if_index = poll_lldp_entry_updates(self.pubsub[inst])
 
             if not data:
                 break
@@ -561,7 +569,7 @@ def _update_per_namespace_data(self, db_conn, pubsub):
 
     def update_data(self):
         for i in range(len(self.db_conn)):
-             self._update_per_namespace_data(self.db_conn[i], self.pubsub[i])
+             self._update_per_namespace_data(i)
 
 
     def reinit_data(self):
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc1213.py b/src/sonic_ax_impl/mibs/ietf/rfc1213.py
index c7dc2848f..c2c3fe8ec 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc1213.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc1213.py
@@ -95,6 +95,7 @@ class NextHopUpdater(MIBUpdater):
     def __init__(self):
         super().__init__()
         self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
         self.nexthop_map = {}
         self.route_list = []
 
@@ -152,7 +153,11 @@ class InterfacesUpdater(MIBUpdater):
 
     def __init__(self):
         super().__init__()
-        self.db_conn = Namespace.init_namespace_dbs() 
+        self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.STATE_DB)
 
         self.lag_name_if_name_map = {}
         self.if_name_lag_name_map = {}
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc2737.py b/src/sonic_ax_impl/mibs/ietf/rfc2737.py
index 4f5a7eb74..79dc9425c 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc2737.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc2737.py
@@ -122,6 +122,8 @@ def __init__(self):
 
         self.statedb = Namespace.init_namespace_dbs()
         Namespace.connect_all_dbs(self.statedb, mibs.STATE_DB)
+        Namespace.connect_all_dbs(self.statedb, mibs.COUNTERS_DB)
+        Namespace.connect_all_dbs(self.statedb, mibs.APPL_DB)
 
         self.if_alias_map = {}
 
@@ -153,7 +155,7 @@ def reinit_data(self):
 
         # update interface maps
         _, self.if_alias_map, _, _, _ = \
-            Namespace.init_namespace_sync_d_interface_tables(Namespace.init_namespace_dbs())
+            Namespace.init_namespace_sync_d_interface_tables(self.statedb)
 
         device_metadata = mibs.get_device_metadata(self.statedb[0])
         chassis_sub_id = (self.CHASSIS_ID, )
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc2863.py b/src/sonic_ax_impl/mibs/ietf/rfc2863.py
index ec575e7d0..6853ab952 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc2863.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc2863.py
@@ -49,6 +49,9 @@ def __init__(self):
         super().__init__()
 
         self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
 
         self.lag_name_if_name_map = {}
         self.if_name_lag_name_map = {}
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc4292.py b/src/sonic_ax_impl/mibs/ietf/rfc4292.py
index c004338bb..b1b16d7df 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc4292.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc4292.py
@@ -11,6 +11,7 @@ def __init__(self):
         super().__init__()
         self.tos = 0 # ipCidrRouteTos
         self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
         self.route_dest_map = {}
         self.route_dest_list = []
         ## loopback ip string -> ip address object
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc4363.py b/src/sonic_ax_impl/mibs/ietf/rfc4363.py
index e9aa46af6..00d2fc2be 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc4363.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc4363.py
@@ -11,6 +11,9 @@ class FdbUpdater(MIBUpdater):
     def __init__(self):
         super().__init__()
         self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, mibs.ASIC_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
 
         self.if_name_map = {}
         self.if_alias_map = {}
diff --git a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py
index 7661016c4..8eb8c732b 100644
--- a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py
+++ b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py
@@ -13,6 +13,8 @@ class PfcUpdater(MIBUpdater):
     def __init__(self):
         super().__init__()
         self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
 
         self.if_name_map = {}
         self.if_alias_map = {}
diff --git a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoSwitchQosMIB.py b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoSwitchQosMIB.py
index 274b71695..5d3cb4616 100644
--- a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoSwitchQosMIB.py
+++ b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoSwitchQosMIB.py
@@ -46,6 +46,8 @@ def __init__(self):
         """
         super().__init__()
         self.db_conn = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
+        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
         self.lag_name_if_name_map = {}
         self.if_name_lag_name_map = {}
         self.oid_lag_name_map = {}
diff --git a/tests/namespace/test_mibs.py b/tests/namespace/test_mibs.py
index b461d09ed..99e9bc6cb 100644
--- a/tests/namespace/test_mibs.py
+++ b/tests/namespace/test_mibs.py
@@ -17,6 +17,8 @@ def setUpClass(cls):
 
     def test_init_namespace_sync_d_lag_tables(self):
         dbs = Namespace.init_namespace_dbs()
+        Namespace.connect_all_dbs(dbs, mibs.APPL_DB)
+        Namespace.connect_all_dbs(dbs, mibs.COUNTERS_DB)
 
         lag_name_if_name_map, \
         if_name_lag_name_map, \
diff --git a/tests/test_mibs.py b/tests/test_mibs.py
index 3c28a89e5..ec7b3f0bc 100644
--- a/tests/test_mibs.py
+++ b/tests/test_mibs.py
@@ -17,6 +17,8 @@ def setUpClass(cls):
 
     def test_init_sync_d_lag_tables(self):
         db_conn = mibs.init_db()
+        db_conn.connect(mibs.APPL_DB)
+        db_conn.connect(mibs.COUNTERS_DB)
 
         lag_name_if_name_map, \
         if_name_lag_name_map, \

From ffe4d38996167caf2813564de3a9c43f4a7a1a2b Mon Sep 17 00:00:00 2001
From: SuvarnaMeenakshi <sumeenak@microsoft.com>
Date: Tue, 16 Jun 2020 11:09:16 -0700
Subject: [PATCH 3/8] Minor fix

Signed-off-by: SuvarnaMeenakshi <sumeenak@microsoft.com>
---
 src/sonic_ax_impl/mibs/ieee802_1ab.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/sonic_ax_impl/mibs/ieee802_1ab.py b/src/sonic_ax_impl/mibs/ieee802_1ab.py
index dd92fc717..89677cc34 100644
--- a/src/sonic_ax_impl/mibs/ieee802_1ab.py
+++ b/src/sonic_ax_impl/mibs/ieee802_1ab.py
@@ -233,7 +233,7 @@ def _update_per_namespace_data(self, inst):
             redis_client = self.db_conn[inst].get_redis_client(self.db_conn[inst].APPL_DB)
             db = self.db_conn[inst].get_dbid(self.db_conn[inst].APPL_DB)
             self.pubsub[inst] = redis_client.pubsub()
-            pubsub.psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
+            self.pubsub[inst].psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
 
         while True:
             data, interface, if_id = poll_lldp_entry_updates(self.pubsub[inst])

From 20dd2e256088a70b8d29dcbdbec535e82ab96d05 Mon Sep 17 00:00:00 2001
From: SuvarnaMeenakshi <sumeenak@microsoft.com>
Date: Tue, 16 Jun 2020 11:10:58 -0700
Subject: [PATCH 4/8] Add mock asic_db.

Signed-off-by: SuvarnaMeenakshi <sumeenak@microsoft.com>
---
 tests/mock_tables/global_db/asic_db.json | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 tests/mock_tables/global_db/asic_db.json

diff --git a/tests/mock_tables/global_db/asic_db.json b/tests/mock_tables/global_db/asic_db.json
new file mode 100644
index 000000000..2c63c0851
--- /dev/null
+++ b/tests/mock_tables/global_db/asic_db.json
@@ -0,0 +1,2 @@
+{
+}

From 50dd045d98327e2762bf2bcae6de1125dd08b5bc Mon Sep 17 00:00:00 2001
From: SuvarnaMeenakshi <sumeenak@microsoft.com>
Date: Tue, 16 Jun 2020 12:45:15 -0700
Subject: [PATCH 5/8] Remove trailing whitespace.

Signed-off-by: SuvarnaMeenakshi <sumeenak@microsoft.com>
---
 src/sonic_ax_impl/mibs/__init__.py                    | 6 +++---
 src/sonic_ax_impl/mibs/ieee802_1ab.py                 | 6 +++---
 src/sonic_ax_impl/mibs/ietf/rfc3433.py                | 4 ++--
 src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py | 2 +-
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/sonic_ax_impl/mibs/__init__.py b/src/sonic_ax_impl/mibs/__init__.py
index 788f54079..00584f9a1 100644
--- a/src/sonic_ax_impl/mibs/__init__.py
+++ b/src/sonic_ax_impl/mibs/__init__.py
@@ -150,7 +150,7 @@ def init_db():
     """
     # SyncD database connector. THIS MUST BE INITIALIZED ON A PER-THREAD BASIS.
     # Redis PubSub objects (such as those within swsssdk) are NOT thread-safe.
-    db_conn = SonicV2Connector(**redis_kwargs) 
+    db_conn = SonicV2Connector(**redis_kwargs)
 
     return db_conn
 
@@ -404,7 +404,7 @@ def update_data(self):
         self.oid_list = []
         self.oid_map = {}
 
-        keys = Namespace.dbs_keys(self.db_conn, SNMP_OVERLAY_DB, self.prefix_str + '*') 
+        keys = Namespace.dbs_keys(self.db_conn, SNMP_OVERLAY_DB, self.prefix_str + '*')
         # TODO: fix db_conn.keys to return empty list instead of None if there is no match
         if keys is None:
             keys = []
@@ -413,7 +413,7 @@ def update_data(self):
             key = key.decode()
             oid = oid2tuple(key, dot_prefix=False)
             self.oid_list.append(oid)
-            value = Namespace.dbs_get_all(self.db_conn, SNMP_OVERLAY_DB, key) 
+            value = Namespace.dbs_get_all(self.db_conn, SNMP_OVERLAY_DB, key)
             if value[b'type'] in [b'COUNTER_32', b'COUNTER_64']:
                 self.oid_map[oid] = int(value[b'data'])
             else:
diff --git a/src/sonic_ax_impl/mibs/ieee802_1ab.py b/src/sonic_ax_impl/mibs/ieee802_1ab.py
index 89677cc34..043c02c52 100644
--- a/src/sonic_ax_impl/mibs/ieee802_1ab.py
+++ b/src/sonic_ax_impl/mibs/ieee802_1ab.py
@@ -160,7 +160,7 @@ def __init__(self):
         # cache of port data
         # { if_name -> { 'key': 'value' } }
         self.loc_port_data = {}
-        self.pubsub = [None] * len(self.db_conn) 
+        self.pubsub = [None] * len(self.db_conn)
 
     def reinit_data(self):
         """
@@ -310,7 +310,7 @@ def reinit_data(self):
         self.mgmt_ip_str = None
 
         # establish connection to application database.
-        self.db_conn.connect(mibs.APPL_DB) 
+        self.db_conn.connect(mibs.APPL_DB)
         mgmt_ip_bytes = self.db_conn.get(mibs.APPL_DB, mibs.LOC_CHASSIS_TABLE, b'lldp_loc_man_addr')
 
         if not mgmt_ip_bytes:
@@ -494,7 +494,7 @@ class LLDPRemManAddrUpdater(MIBUpdater):
     def __init__(self):
         super().__init__()
 
-        self.db_conn = Namespace.init_namespace_dbs() 
+        self.db_conn = Namespace.init_namespace_dbs()
         # establish connection to application database.
         Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
         Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc3433.py b/src/sonic_ax_impl/mibs/ietf/rfc3433.py
index 4c0754f99..4e97b2bab 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc3433.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc3433.py
@@ -250,7 +250,7 @@ def __init__(self):
 
         super().__init__()
 
-        self.statedb = Namespace.init_namespace_dbs() 
+        self.statedb = Namespace.init_namespace_dbs()
         Namespace.connect_all_dbs(self.statedb, mibs.STATE_DB)
 
         # list of available sub OIDs
@@ -378,7 +378,7 @@ def get_ent_physical_sensor_precision(self, sub_id):
         """
         Get sensor precision value based on sub OID
         :param sub_id: sub ID of the sensor
-        :return: sensor precision in range (-8, 9) 
+        :return: sensor precision in range (-8, 9)
                  or None if sub_id not in the cache.
         """
 
diff --git a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py
index 8eb8c732b..ce1859bdf 100644
--- a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py
+++ b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py
@@ -193,7 +193,7 @@ def requests_per_priority(self, sub_id):
         """
         :param sub_id: The 0-based sub-identifier query.
         :return: the counter for the respective sub_id/table.
-        """        
+        """
         port_oid = ''
         queue_index = ''
         try:

From 1eb43dfc14bcd585720a2dd84bfa8081974f995a Mon Sep 17 00:00:00 2001
From: SuvarnaMeenakshi <sumeenak@microsoft.com>
Date: Wed, 24 Jun 2020 11:31:06 -0700
Subject: [PATCH 6/8] Revert "Make sure that db connections are done in MIB
 class init"

This reverts commit 1dced6e497b95a8bde631346a682961ef8a9b862.
---
 src/sonic_ax_impl/mibs/__init__.py            | 22 +++++++++++++++--
 src/sonic_ax_impl/mibs/ieee802_1ab.py         | 24 +++++++------------
 src/sonic_ax_impl/mibs/ietf/rfc1213.py        |  7 +-----
 src/sonic_ax_impl/mibs/ietf/rfc2737.py        |  4 +---
 src/sonic_ax_impl/mibs/ietf/rfc2863.py        |  3 ---
 src/sonic_ax_impl/mibs/ietf/rfc4292.py        |  1 -
 src/sonic_ax_impl/mibs/ietf/rfc4363.py        |  3 ---
 .../mibs/vendor/cisco/ciscoPfcExtMIB.py       |  2 --
 .../mibs/vendor/cisco/ciscoSwitchQosMIB.py    |  2 --
 tests/namespace/test_mibs.py                  |  2 --
 tests/test_mibs.py                            |  2 --
 11 files changed, 30 insertions(+), 42 deletions(-)

diff --git a/src/sonic_ax_impl/mibs/__init__.py b/src/sonic_ax_impl/mibs/__init__.py
index 00584f9a1..18e522ef8 100644
--- a/src/sonic_ax_impl/mibs/__init__.py
+++ b/src/sonic_ax_impl/mibs/__init__.py
@@ -160,6 +160,10 @@ def init_mgmt_interface_tables(db_conn):
     :param db_conn: db connector
     :return: tuple of mgmt name to oid map and mgmt name to alias map
     """
+
+    db_conn.connect(CONFIG_DB)
+    db_conn.connect(STATE_DB)
+
     mgmt_ports_keys = db_conn.keys(CONFIG_DB, mgmt_if_entry_table(b'*'))
 
     if not mgmt_ports_keys:
@@ -186,6 +190,9 @@ def init_sync_d_interface_tables(db_conn):
     :return: tuple(if_name_map, if_id_map, oid_map, if_alias_map)
     """
 
+    # Make sure we're connected to COUNTERS_DB
+    db_conn.connect(COUNTERS_DB)
+
     # { if_name (SONiC) -> sai_id }
     # ex: { "Ethernet76" : "1000000000023" }
     if_name_map, if_id_map = port_util.get_interface_oid_map(db_conn)
@@ -225,6 +232,8 @@ def init_sync_d_interface_tables(db_conn):
                        .format(port_util.SONIC_ETHERNET_RE_PATTERN))
         logger.warning("Port name map:\n" + pprint.pformat(if_name_map, indent=2))
 
+    db_conn.connect(APPL_DB)
+
     if_alias_map = dict()
 
     for if_name in if_name_map:
@@ -250,6 +259,8 @@ def init_sync_d_lag_tables(db_conn):
     # { OID -> lag_name (SONiC) }
     oid_lag_name_map = {}
 
+    db_conn.connect(APPL_DB)
+
     lag_entries = db_conn.keys(APPL_DB, b"LAG_TABLE:*")
 
     if not lag_entries:
@@ -282,6 +293,10 @@ def init_sync_d_queue_tables(db_conn):
     Initializes queue maps for SyncD-connected MIB(s).
     :return: tuple(port_queues_map, queue_stat_map)
     """
+
+    # Make sure we're connected to COUNTERS_DB
+    db_conn.connect(COUNTERS_DB)
+
     # { Port index : Queue index (SONiC) -> sai_id }
     # ex: { "1:2" : "1000000000023" }
     queue_name_map = db_conn.get_all(COUNTERS_DB, COUNTERS_QUEUE_NAME_MAP, blocking=True)
@@ -334,6 +349,7 @@ def get_device_metadata(db_conn):
     """
 
     DEVICE_METADATA = "DEVICE_METADATA|localhost"
+    db_conn.connect(db_conn.STATE_DB)
 
     device_metadata = db_conn.get_all(db_conn.STATE_DB, DEVICE_METADATA)
     return device_metadata
@@ -377,8 +393,7 @@ class RedisOidTreeUpdater(MIBUpdater):
     def __init__(self, prefix_str):
         super().__init__()
 
-        self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, SNMP_OVERLAY_DB)
+        self.db_conn = Namespace.init_namespace_dbs() 
         if prefix_str.startswith('.'):
             prefix_str = prefix_str[1:]
         self.prefix_str = prefix_str
@@ -449,6 +464,7 @@ def dbs_keys(dbs, db_name, pattern='*'):
         """
         result_keys=[]
         for db_conn in dbs:
+            db_conn.connect(db_name)
             keys = db_conn.keys(db_name, pattern)
             if keys is not None:
                 result_keys.extend(keys)
@@ -461,6 +477,7 @@ def dbs_get_all(dbs, db_name, _hash, *args, **kwargs):
         """
         result = {}
         for db_conn in dbs:
+            db_conn.connect(db_name)
             if(db_conn.exists(db_name, _hash)):
                 ns_result = db_conn.get_all(db_name, _hash, *args, **kwargs)
                 if ns_result is not None:
@@ -569,6 +586,7 @@ def dbs_get_bridge_port_map(dbs, db_name):
     @staticmethod
     def dbs_get_vlan_id_from_bvid(dbs, bvid):
         for db_conn in Namespace.get_non_host_dbs(dbs):
+            db_conn.connect('ASIC_DB')
             vlan_obj = db_conn.keys('ASIC_DB', "ASIC_STATE:SAI_OBJECT_TYPE_VLAN:" + bvid)
             if vlan_obj is not None:
                 return port_util.get_vlan_id_from_bvid(db_conn, bvid)
diff --git a/src/sonic_ax_impl/mibs/ieee802_1ab.py b/src/sonic_ax_impl/mibs/ieee802_1ab.py
index 043c02c52..0d0feab57 100644
--- a/src/sonic_ax_impl/mibs/ieee802_1ab.py
+++ b/src/sonic_ax_impl/mibs/ieee802_1ab.py
@@ -104,7 +104,6 @@ def __init__(self):
         super().__init__()
 
         self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
         self.loc_chassis_data = {}
 
     def reinit_data(self):
@@ -144,8 +143,6 @@ def __init__(self):
         self.db_conn = Namespace.init_namespace_dbs()
         # establish connection to application database.
         Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
         self.if_name_map = {}
         self.if_alias_map = {}
         self.if_id_map = {}
@@ -386,9 +383,6 @@ def __init__(self):
         super().__init__()
 
         self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
         self.if_name_map = {}
         self.if_alias_map = {}
         self.if_id_map = {}
@@ -497,8 +491,6 @@ def __init__(self):
         self.db_conn = Namespace.init_namespace_dbs()
         # establish connection to application database.
         Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
         self.if_range = []
         self.mgmt_ips = {}
         self.oid_name_map = {}
@@ -544,18 +536,18 @@ def update_rem_if_mgmt(self, if_oid, if_name):
             return
         self.if_range.sort()
 
-    def _update_per_namespace_data(self, inst):
+    def _update_per_namespace_data(self, db_conn, pubsub):
         """
         Listen to updates in APP DB, update local cache
         """
-        if not self.pubsub[inst]:
-            redis_client = self.db_conn[inst].get_redis_client(self.db_conn[inst].APPL_DB)
-            db = self.db_conn[inst].get_dbid(self.db_conn[inst].APPL_DB)
-            self.pubsub[inst] = redis_client.pubsub()
-            self.pubsub[inst].psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
+        if not pubsub:
+            redis_client = db_conn.get_redis_client(db_conn.APPL_DB)
+            db = db_conn.get_dbid(db_conn.APPL_DB)
+            pubsub = redis_client.pubsub()
+            pubsub.psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
 
         while True:
-            data, interface, if_index = poll_lldp_entry_updates(self.pubsub[inst])
+            data, interface, if_index = poll_lldp_entry_updates(pubsub)
 
             if not data:
                 break
@@ -569,7 +561,7 @@ def _update_per_namespace_data(self, inst):
 
     def update_data(self):
         for i in range(len(self.db_conn)):
-             self._update_per_namespace_data(i)
+             self._update_per_namespace_data(self.db_conn[i], self.pubsub[i])
 
 
     def reinit_data(self):
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc1213.py b/src/sonic_ax_impl/mibs/ietf/rfc1213.py
index c2c3fe8ec..c7dc2848f 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc1213.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc1213.py
@@ -95,7 +95,6 @@ class NextHopUpdater(MIBUpdater):
     def __init__(self):
         super().__init__()
         self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
         self.nexthop_map = {}
         self.route_list = []
 
@@ -153,11 +152,7 @@ class InterfacesUpdater(MIBUpdater):
 
     def __init__(self):
         super().__init__()
-        self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.STATE_DB)
+        self.db_conn = Namespace.init_namespace_dbs() 
 
         self.lag_name_if_name_map = {}
         self.if_name_lag_name_map = {}
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc2737.py b/src/sonic_ax_impl/mibs/ietf/rfc2737.py
index 79dc9425c..4f5a7eb74 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc2737.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc2737.py
@@ -122,8 +122,6 @@ def __init__(self):
 
         self.statedb = Namespace.init_namespace_dbs()
         Namespace.connect_all_dbs(self.statedb, mibs.STATE_DB)
-        Namespace.connect_all_dbs(self.statedb, mibs.COUNTERS_DB)
-        Namespace.connect_all_dbs(self.statedb, mibs.APPL_DB)
 
         self.if_alias_map = {}
 
@@ -155,7 +153,7 @@ def reinit_data(self):
 
         # update interface maps
         _, self.if_alias_map, _, _, _ = \
-            Namespace.init_namespace_sync_d_interface_tables(self.statedb)
+            Namespace.init_namespace_sync_d_interface_tables(Namespace.init_namespace_dbs())
 
         device_metadata = mibs.get_device_metadata(self.statedb[0])
         chassis_sub_id = (self.CHASSIS_ID, )
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc2863.py b/src/sonic_ax_impl/mibs/ietf/rfc2863.py
index 6853ab952..ec575e7d0 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc2863.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc2863.py
@@ -49,9 +49,6 @@ def __init__(self):
         super().__init__()
 
         self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.CONFIG_DB)
 
         self.lag_name_if_name_map = {}
         self.if_name_lag_name_map = {}
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc4292.py b/src/sonic_ax_impl/mibs/ietf/rfc4292.py
index b1b16d7df..c004338bb 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc4292.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc4292.py
@@ -11,7 +11,6 @@ def __init__(self):
         super().__init__()
         self.tos = 0 # ipCidrRouteTos
         self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
         self.route_dest_map = {}
         self.route_dest_list = []
         ## loopback ip string -> ip address object
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc4363.py b/src/sonic_ax_impl/mibs/ietf/rfc4363.py
index 00d2fc2be..e9aa46af6 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc4363.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc4363.py
@@ -11,9 +11,6 @@ class FdbUpdater(MIBUpdater):
     def __init__(self):
         super().__init__()
         self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, mibs.ASIC_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
 
         self.if_name_map = {}
         self.if_alias_map = {}
diff --git a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py
index ce1859bdf..77ee7f88e 100644
--- a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py
+++ b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoPfcExtMIB.py
@@ -13,8 +13,6 @@ class PfcUpdater(MIBUpdater):
     def __init__(self):
         super().__init__()
         self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
 
         self.if_name_map = {}
         self.if_alias_map = {}
diff --git a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoSwitchQosMIB.py b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoSwitchQosMIB.py
index 5d3cb4616..274b71695 100644
--- a/src/sonic_ax_impl/mibs/vendor/cisco/ciscoSwitchQosMIB.py
+++ b/src/sonic_ax_impl/mibs/vendor/cisco/ciscoSwitchQosMIB.py
@@ -46,8 +46,6 @@ def __init__(self):
         """
         super().__init__()
         self.db_conn = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(self.db_conn, mibs.COUNTERS_DB)
-        Namespace.connect_all_dbs(self.db_conn, mibs.APPL_DB)
         self.lag_name_if_name_map = {}
         self.if_name_lag_name_map = {}
         self.oid_lag_name_map = {}
diff --git a/tests/namespace/test_mibs.py b/tests/namespace/test_mibs.py
index 99e9bc6cb..b461d09ed 100644
--- a/tests/namespace/test_mibs.py
+++ b/tests/namespace/test_mibs.py
@@ -17,8 +17,6 @@ def setUpClass(cls):
 
     def test_init_namespace_sync_d_lag_tables(self):
         dbs = Namespace.init_namespace_dbs()
-        Namespace.connect_all_dbs(dbs, mibs.APPL_DB)
-        Namespace.connect_all_dbs(dbs, mibs.COUNTERS_DB)
 
         lag_name_if_name_map, \
         if_name_lag_name_map, \
diff --git a/tests/test_mibs.py b/tests/test_mibs.py
index ec7b3f0bc..3c28a89e5 100644
--- a/tests/test_mibs.py
+++ b/tests/test_mibs.py
@@ -17,8 +17,6 @@ def setUpClass(cls):
 
     def test_init_sync_d_lag_tables(self):
         db_conn = mibs.init_db()
-        db_conn.connect(mibs.APPL_DB)
-        db_conn.connect(mibs.COUNTERS_DB)
 
         lag_name_if_name_map, \
         if_name_lag_name_map, \

From 3442ff96abb84a61b32bc94d0b760db36c78f282 Mon Sep 17 00:00:00 2001
From: SuvarnaMeenakshi <sumeenak@microsoft.com>
Date: Wed, 24 Jun 2020 11:33:30 -0700
Subject: [PATCH 7/8] Fix to make sure pubsub channel in LLDPRemManAddrUpdater
 is not created everytime in update_data but is created only if the channel
 was not created previously.

Signed-off-by: SuvarnaMeenakshi <sumeenak@microsoft.com>
---
 src/sonic_ax_impl/mibs/ieee802_1ab.py | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/sonic_ax_impl/mibs/ieee802_1ab.py b/src/sonic_ax_impl/mibs/ieee802_1ab.py
index 0d0feab57..78c125e52 100644
--- a/src/sonic_ax_impl/mibs/ieee802_1ab.py
+++ b/src/sonic_ax_impl/mibs/ieee802_1ab.py
@@ -536,18 +536,18 @@ def update_rem_if_mgmt(self, if_oid, if_name):
             return
         self.if_range.sort()
 
-    def _update_per_namespace_data(self, db_conn, pubsub):
+    def _update_per_namespace_data(self, inst):
         """
         Listen to updates in APP DB, update local cache
         """
-        if not pubsub:
-            redis_client = db_conn.get_redis_client(db_conn.APPL_DB)
-            db = db_conn.get_dbid(db_conn.APPL_DB)
-            pubsub = redis_client.pubsub()
-            pubsub.psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
+        if not self.pubsub[inst]:
+            redis_client = self.db_conn[inst].get_redis_client(self.db_conn[inst].APPL_DB)
+            db = self.db_conn[inst].get_dbid(self.db_conn[inst].APPL_DB)
+            self.pubsub[inst] = redis_client.pubsub()
+            self.pubsub[inst].psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
 
         while True:
-            data, interface, if_index = poll_lldp_entry_updates(pubsub)
+            data, interface, if_index = poll_lldp_entry_updates(self.pubsub[inst])
 
             if not data:
                 break
@@ -561,7 +561,7 @@ def _update_per_namespace_data(self, db_conn, pubsub):
 
     def update_data(self):
         for i in range(len(self.db_conn)):
-             self._update_per_namespace_data(self.db_conn[i], self.pubsub[i])
+             self._update_per_namespace_data(i)
 
 
     def reinit_data(self):

From ea91aca896a9e7a4e1ec80d2d288dd75f541cda0 Mon Sep 17 00:00:00 2001
From: SuvarnaMeenakshi <sumeenak@microsoft.com>
Date: Thu, 25 Jun 2020 00:21:35 -0700
Subject: [PATCH 8/8] Fix as per review comments.

Signed-off-by: SuvarnaMeenakshi <sumeenak@microsoft.com>
---
 src/sonic_ax_impl/mibs/__init__.py     |  7 ++++++
 src/sonic_ax_impl/mibs/ieee802_1ab.py  | 31 ++++++++++----------------
 src/sonic_ax_impl/mibs/ietf/rfc2737.py | 17 +++++++-------
 3 files changed, 27 insertions(+), 28 deletions(-)

diff --git a/src/sonic_ax_impl/mibs/__init__.py b/src/sonic_ax_impl/mibs/__init__.py
index 18e522ef8..e9353861d 100644
--- a/src/sonic_ax_impl/mibs/__init__.py
+++ b/src/sonic_ax_impl/mibs/__init__.py
@@ -389,6 +389,13 @@ def get_transceiver_sensor_sub_id(ifindex, sensor):
     transceiver_oid, = get_transceiver_sub_id(ifindex)
     return (transceiver_oid + SENSOR_PART_ID_MAP[sensor], )
 
+def get_redis_pubsub(db_conn, db_name, pattern):
+    redis_client = db_conn.get_redis_client(db_name)
+    db = db_conn.get_dbid(db_name)
+    pubsub = redis_client.pubsub()
+    pubsub.psubscribe("__keyspace@{}__:{}".format(db, pattern))
+    return pubsub
+
 class RedisOidTreeUpdater(MIBUpdater):
     def __init__(self, prefix_str):
         super().__init__()
diff --git a/src/sonic_ax_impl/mibs/ieee802_1ab.py b/src/sonic_ax_impl/mibs/ieee802_1ab.py
index 78c125e52..6b36ff866 100644
--- a/src/sonic_ax_impl/mibs/ieee802_1ab.py
+++ b/src/sonic_ax_impl/mibs/ieee802_1ab.py
@@ -71,7 +71,6 @@ class ManAddrConst:
     """
     man_addr_oid = (1, 3, 6, 1, 2, 1, 2, 2, 1, 1)
 
-
 def poll_lldp_entry_updates(pubsub):
     ret = None, None, None
     msg = pubsub.get_message()
@@ -222,18 +221,12 @@ def get_next(self, sub_id):
             return None
         return self.if_range[right]
 
-    def _update_per_namespace_data(self, inst):
+    def _update_per_namespace_data(self, pubsub):
         """
         Listen to updates in APP DB, update local cache
         """
-        if not self.pubsub[inst]:
-            redis_client = self.db_conn[inst].get_redis_client(self.db_conn[inst].APPL_DB)
-            db = self.db_conn[inst].get_dbid(self.db_conn[inst].APPL_DB)
-            self.pubsub[inst] = redis_client.pubsub()
-            self.pubsub[inst].psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
-
         while True:
-            data, interface, if_id = poll_lldp_entry_updates(self.pubsub[inst])
+            data, interface, if_id = poll_lldp_entry_updates(pubsub)
 
             if not data:
                 break
@@ -243,7 +236,10 @@ def _update_per_namespace_data(self, inst):
 
     def update_data(self):
         for i in range(len(self.db_conn)):
-            self._update_per_namespace_data(i)
+            if not self.pubsub[i]:
+                pattern = mibs.lldp_entry_table(b'*')
+                self.pubsub[i] = mibs.get_redis_pubsub(self.db_conn[i], self.db_conn[i].APPL_DB, pattern)
+            self._update_per_namespace_data(self.pubsub[i])
 
     def local_port_num(self, sub_id):
         if len(sub_id) == 0:
@@ -536,18 +532,12 @@ def update_rem_if_mgmt(self, if_oid, if_name):
             return
         self.if_range.sort()
 
-    def _update_per_namespace_data(self, inst):
+    def _update_per_namespace_data(self, pubsub):
         """
         Listen to updates in APP DB, update local cache
         """
-        if not self.pubsub[inst]:
-            redis_client = self.db_conn[inst].get_redis_client(self.db_conn[inst].APPL_DB)
-            db = self.db_conn[inst].get_dbid(self.db_conn[inst].APPL_DB)
-            self.pubsub[inst] = redis_client.pubsub()
-            self.pubsub[inst].psubscribe("__keyspace@{}__:{}".format(db, mibs.lldp_entry_table(b'*')))
-
         while True:
-            data, interface, if_index = poll_lldp_entry_updates(self.pubsub[inst])
+            data, interface, if_index = poll_lldp_entry_updates(pubsub)
 
             if not data:
                 break
@@ -561,7 +551,10 @@ def _update_per_namespace_data(self, inst):
 
     def update_data(self):
         for i in range(len(self.db_conn)):
-             self._update_per_namespace_data(i)
+            if not self.pubsub[i]:
+                pattern = mibs.lldp_entry_table(b'*')
+                self.pubsub[i] = mibs.get_redis_pubsub(self.db_conn[i], self.db_conn[i].APPL_DB, pattern)
+            self._update_per_namespace_data(self.pubsub[i])
 
 
     def reinit_data(self):
diff --git a/src/sonic_ax_impl/mibs/ietf/rfc2737.py b/src/sonic_ax_impl/mibs/ietf/rfc2737.py
index 4f5a7eb74..b503967d1 100644
--- a/src/sonic_ax_impl/mibs/ietf/rfc2737.py
+++ b/src/sonic_ax_impl/mibs/ietf/rfc2737.py
@@ -181,7 +181,7 @@ def reinit_data(self):
             interface = transceiver_entry.split(mibs.TABLE_NAME_SEPARATOR_VBAR)[-1]
             self._update_transceiver_cache(interface)
 
-    def _update_per_namespace_data(self, inst):
+    def _update_per_namespace_data(self, pubsub):
         """
         Update cache.
         Here we listen to changes in STATE_DB TRANSCEIVER_INFO table
@@ -190,14 +190,8 @@ def _update_per_namespace_data(self, inst):
 
         # This code is not executed in unit test, since mockredis
         # does not support pubsub
-        if not self.pubsub[inst]:
-            redis_client = self.statedb[inst].get_redis_client(self.statedb[inst].STATE_DB)
-            db = self.statedb[inst].get_dbid(self.statedb[inst].STATE_DB)
-            self.pubsub[inst] = redis_client.pubsub()
-            self.pubsub[inst].psubscribe("__keyspace@{}__:{}".format(db, self.TRANSCEIVER_KEY_PATTERN))
-
         while True:
-            msg = self.pubsub[inst].get_message()
+            msg = pubsub.get_message()
 
             if not msg:
                 break
@@ -233,8 +227,13 @@ def _update_per_namespace_data(self, inst):
                         self.physical_entities.remove(sub_id)
 
     def update_data(self):
+        # This code is not executed in unit test, since mockredis
+        # does not support pubsub
         for i in range(len(self.statedb)):
-             self._update_per_namespace_data(i)
+            if not self.pubsub[i]:
+                pattern = self.TRANSCEIVER_KEY_PATTERN
+                self.pubsub[i] = mibs.get_redis_pubsub(self.statedb[i], self.statedb[i].STATE_DB, pattern)
+            self._update_per_namespace_data(self.pubsub[i])
 
     def _update_transceiver_cache(self, interface):
         """