diff --git a/heat/engine/sync_point.py b/heat/engine/sync_point.py
index 8e18eb5a2a..b0f08adc45 100644
--- a/heat/engine/sync_point.py
+++ b/heat/engine/sync_point.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import ast
 from oslo_log import log as logging
 import six
 
@@ -75,16 +76,47 @@ def update_input_data(context, entity_id, current_traversal,
     return rows_updated
 
 
+def _str_pack_tuple(t):
+    return u'tuple:' + str(t)
+
+
+def _str_unpack_tuple(s):
+    s = s[s.index(':') + 1:]
+    return ast.literal_eval(s)
+
+
+def _deserialize(d):
+    d2 = {}
+    for k, v in d.items():
+        if isinstance(k, six.string_types) and k.startswith(u'tuple:('):
+            k = _str_unpack_tuple(k)
+        if isinstance(v, dict):
+            v = _deserialize(v)
+        d2[k] = v
+    return d2
+
+
+def _serialize(d):
+    d2 = {}
+    for k, v in d.items():
+        if isinstance(k, tuple):
+            k = _str_pack_tuple(k)
+        if isinstance(v, dict):
+            v = _serialize(v)
+        d2[k] = v
+    return d2
+
+
 def deserialize_input_data(db_input_data):
     db_input_data = db_input_data.get('input_data')
     if not db_input_data:
         return {}
 
-    return {tuple(i): j for i, j in db_input_data}
+    return dict(_deserialize(db_input_data))
 
 
 def serialize_input_data(input_data):
-    return {'input_data': [[list(i), j] for i, j in six.iteritems(input_data)]}
+    return {'input_data': _serialize(input_data)}
 
 
 def sync(cnxt, entity_id, current_traversal, is_update, propagate,
@@ -95,7 +127,7 @@ def sync(cnxt, entity_id, current_traversal, is_update, propagate,
     while not rows_updated:
         # TODO(sirushtim): Add a conf option to add no. of retries
         sync_point = get(cnxt, entity_id, current_traversal, is_update)
-        input_data = dict(deserialize_input_data(sync_point.input_data))
+        input_data = deserialize_input_data(sync_point.input_data)
         input_data.update(new_data)
         rows_updated = update_input_data(
             cnxt, entity_id, current_traversal, is_update,
diff --git a/heat/tests/engine/test_sync_point.py b/heat/tests/engine/test_sync_point.py
index 375d8103a0..f10aaf9b1e 100644
--- a/heat/tests/engine/test_sync_point.py
+++ b/heat/tests/engine/test_sync_point.py
@@ -65,4 +65,4 @@ class SyncPointTestCase(common.HeatTestCase):
 
     def test_serialize_input_data(self):
         res = sync_point.serialize_input_data({(3, 8): None})
-        self.assertEqual({'input_data': [[[3, 8], None]]}, res)
+        self.assertEqual({'input_data': {u'tuple:(3, 8)': None}}, res)
diff --git a/heat/tests/test_convg_stack.py b/heat/tests/test_convg_stack.py
index 61c5a4f733..eecae5640f 100644
--- a/heat/tests/test_convg_stack.py
+++ b/heat/tests/test_convg_stack.py
@@ -70,7 +70,7 @@ class StackConvergenceCreateUpdateDeleteTest(common.HeatTestCase):
             expected_calls.append(
                 mock.call.worker_client.WorkerClient.check_resource(
                     stack.context, rsrc_id, stack.current_traversal,
-                    {'input_data': []},
+                    {'input_data': {}},
                     is_update, None))
         self.assertEqual(expected_calls, mock_cr.mock_calls)
 
@@ -127,7 +127,7 @@ class StackConvergenceCreateUpdateDeleteTest(common.HeatTestCase):
             expected_calls.append(
                 mock.call.worker_client.WorkerClient.check_resource(
                     stack.context, rsrc_id, stack.current_traversal,
-                    {'input_data': []},
+                    {'input_data': {}},
                     is_update, None))
         self.assertEqual(expected_calls, mock_cr.mock_calls)
 
@@ -265,7 +265,7 @@ class StackConvergenceCreateUpdateDeleteTest(common.HeatTestCase):
             expected_calls.append(
                 mock.call.worker_client.WorkerClient.check_resource(
                     stack.context, rsrc_id, stack.current_traversal,
-                    {'input_data': []},
+                    {'input_data': {}},
                     is_update, None))
 
         leaves = curr_stack.convergence_dependencies.leaves()
@@ -273,7 +273,7 @@ class StackConvergenceCreateUpdateDeleteTest(common.HeatTestCase):
             expected_calls.append(
                 mock.call.worker_client.WorkerClient.check_resource(
                     curr_stack.context, rsrc_id, curr_stack.current_traversal,
-                    {'input_data': []},
+                    {'input_data': {}},
                     is_update, None))
         self.assertEqual(expected_calls, mock_cr.mock_calls)
 
@@ -347,7 +347,7 @@ class StackConvergenceCreateUpdateDeleteTest(common.HeatTestCase):
             expected_calls.append(
                 mock.call.worker_client.WorkerClient.check_resource(
                     stack.context, rsrc_id, stack.current_traversal,
-                    {'input_data': []},
+                    {'input_data': {}},
                     is_update, None))
 
         leaves = curr_stack.convergence_dependencies.leaves()
@@ -355,7 +355,7 @@ class StackConvergenceCreateUpdateDeleteTest(common.HeatTestCase):
             expected_calls.append(
                 mock.call.worker_client.WorkerClient.check_resource(
                     curr_stack.context, rsrc_id, curr_stack.current_traversal,
-                    {'input_data': []},
+                    {'input_data': {}},
                     is_update, None))
         self.assertEqual(expected_calls, mock_cr.mock_calls)