diff --git a/awx/api/generics.py b/awx/api/generics.py
index 7a818722bc..e474a1bafc 100644
--- a/awx/api/generics.py
+++ b/awx/api/generics.py
@@ -370,7 +370,7 @@ class SubListCreateAttachDetachAPIView(SubListCreateAPIView):
     # Base class for a sublist view that allows for creating subobjects and
     # attaching/detaching them from the parent.
 
-    def is_valid_relation(self, parent, sub):
+    def is_valid_relation(self, parent, sub, created=False):
         return None
 
     def get_description_context(self):
@@ -410,7 +410,7 @@ class SubListCreateAttachDetachAPIView(SubListCreateAPIView):
             raise PermissionDenied()
 
         # Verify that the relationship to be added is valid.
-        attach_errors = self.is_valid_relation(parent, sub)
+        attach_errors = self.is_valid_relation(parent, sub, created=created)
         if attach_errors is not None:
             if created:
                 sub.delete()
diff --git a/awx/api/views.py b/awx/api/views.py
index 910eae869b..84306332b0 100644
--- a/awx/api/views.py
+++ b/awx/api/views.py
@@ -69,7 +69,6 @@ from awx.api.renderers import * # noqa
 from awx.api.serializers import * # noqa
 from awx.api.metadata import RoleMetadata
 from awx.main.consumers import emit_channel_notification
-from awx.main.scheduler.dag_simple import SimpleDAG
 
 logger = logging.getLogger('awx.api.views')
 
@@ -2657,31 +2656,36 @@ class WorkflowJobTemplateNodeChildrenBaseList(EnforceParentRelationshipMixin, Su
         self.check_parent_access(parent)
         return getattr(parent, self.relationship).all()
 
-    def is_valid_relation(self, parent, sub):
-        workflow_nodes = parent.workflow_job_template.workflow_job_template_nodes.all()
-        graph = SimpleDAG()
+    def is_valid_relation(self, parent, sub, created=False):
+        if created:
+            return None
+
+        workflow_nodes = parent.workflow_job_template.workflow_job_template_nodes.all().\
+            prefetch_related('success_nodes', 'failure_nodes', 'always_nodes')
+        graph = {}
         for workflow_node in workflow_nodes:
-            graph.add_node(workflow_node)
+            graph[workflow_node.pk] = dict(node_object=workflow_node, metadata={'parent': None})
 
         find = False
         for node_type in ['success_nodes', 'failure_nodes', 'always_nodes']:
             for workflow_node in workflow_nodes:
-                related_nodes = getattr(workflow_node, node_type).all()
+                parent_node = graph[workflow_node.pk]
+                related_nodes = getattr(parent_node['node_object'], node_type).all()
                 for related_node in related_nodes:
-                    graph.add_edge(workflow_node, related_node, node_type)
-                    if (not find and
-                        parent == workflow_node and
-                        sub == related_node and
-                        self.relationship == node_type):
+                    sub_node = graph[related_node.pk]
+                    sub_node['metadata']['parent'] = parent_node
+                    if not find and parent == workflow_node and sub == related_node and self.relationship == node_type:
                         find = True
         if not find:
-            graph.add_edge(parent, sub, self.relationship)
-
-        if graph.cycle_detected():
-            return {"Error": "Cycle detected!"}
-
-        if graph.multi_ancestor_detected():
-            return {"Error": "Multiple ancestor detected!"}
+            sub_node = graph[sub.pk]
+            parent_node = graph[parent.pk]
+            if sub_node['metadata']['parent'] is not None:
+                return {"Error": "Multiple ancestor detected!"}
+            iter_node = parent_node
+            while iter_node is not None:
+                if iter_node == sub_node:
+                    return {"Error": "Cycle detected!"}
+                iter_node = iter_node['metadata']['parent']
 
         return None
 
diff --git a/awx/main/scheduler/dag_simple.py b/awx/main/scheduler/dag_simple.py
index e629eccd98..c6aa6247c0 100644
--- a/awx/main/scheduler/dag_simple.py
+++ b/awx/main/scheduler/dag_simple.py
@@ -137,53 +137,3 @@ class SimpleDAG(object):
             if len(self.get_dependents(n['node_object'])) < 1:
                 roots.append(n)
         return roots
-
-    def _find_cycle(self, node):
-        stack = [node]
-        node['metadata']['color'] = 'gray'
-
-        while len(stack) > 0:
-            if stack[-1]['metadata']['count'] == len(stack[-1]['metadata']['adj_list']):
-                stack[-1]['metadata']['color'] = 'black'
-                stack.pop()
-            else:
-                to_push = stack[-1]['metadata']['adj_list'][stack[-1]['metadata']['count']]
-                stack[-1]['metadata']['count'] += 1
-                if to_push['metadata']['color'] == 'gray':
-                    return True
-                elif to_push['metadata']['color'] == 'white':
-                    to_push['metadata']['color'] = 'gray'
-                    stack.append(to_push)
-
-        return False
-
-    def _clean_meta(self):
-        for node in self.nodes:
-            node['metadata'] = None
-
-    def cycle_detected(self):
-        for node in self.nodes:
-            node['metadata'] = {"adj_list": [], "color": "white", "count": 0}
-        for edge in self.edges:
-            self.nodes[edge[0]]['metadata']['adj_list'].append(self.nodes[edge[1]])
-
-        for node in self.nodes:
-            if node['metadata']['color'] == 'white' and self._find_cycle(node):
-                self._clean_meta()
-                return True
-
-        self._clean_meta()
-        return False
-
-    def multi_ancestor_detected(self):
-        for node in self.nodes:
-            node['metadata'] = {"ancestor": None}
-        for edge in self.edges:
-            if self.nodes[edge[1]]['metadata']['ancestor'] is None:
-                self.nodes[edge[1]]['metadata']['ancestor'] = self.nodes[edge[0]]
-            else:
-                self._clean_meta()
-                return True
-
-        self._clean_meta()
-        return False