From 98f8faa349f9f650b955efc44a4cddd4337d243c Mon Sep 17 00:00:00 2001
From: AlanCoding <arominge@redhat.com>
Date: Tue, 12 Dec 2017 14:25:58 -0500
Subject: [PATCH] simplify query for active_count

---
 awx/main/managers.py                          | 16 ++++++++-----
 .../tests/functional/models/test_inventory.py | 24 +++++++++++++++++++
 2 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/awx/main/managers.py b/awx/main/managers.py
index 69d4a24b6b..aa478cb027 100644
--- a/awx/main/managers.py
+++ b/awx/main/managers.py
@@ -7,7 +7,7 @@ import logging
 
 from django.db import models
 from django.utils.timezone import now
-from django.db.models import Sum, Q
+from django.db.models import Sum
 from django.conf import settings
 
 from awx.main.utils.filters import SmartFilter
@@ -21,11 +21,15 @@ class HostManager(models.Manager):
     """Custom manager class for Hosts model."""
 
     def active_count(self):
-        """Return count of active, unique hosts for licensing. Exclude ones source from another Tower"""
-        try:
-            return self.filter(~Q(inventory_sources__source='tower')).order_by('name').distinct('name').count()
-        except NotImplementedError: # For unit tests only, SQLite doesn't support distinct('name')
-            return len(set(self.values_list('name', flat=True)))
+        """Return count of active, unique hosts for licensing.
+        Construction of query involves:
+         - remove any ordering specified in model's Meta
+         - Exclude hosts sourced from another Tower
+         - Restrict the query to only return the name column
+         - Only consider results that are unique
+         - Return the count of this query
+        """
+        return self.order_by().exclude(inventory_sources__source='tower').values('name').distinct().count()
 
     def get_queryset(self):
         """When the parent instance of the host query set has a `kind=smart` and a `host_filter`
diff --git a/awx/main/tests/functional/models/test_inventory.py b/awx/main/tests/functional/models/test_inventory.py
index 35c5a63d4f..7a537e6a2a 100644
--- a/awx/main/tests/functional/models/test_inventory.py
+++ b/awx/main/tests/functional/models/test_inventory.py
@@ -35,6 +35,30 @@ class TestInventoryScript:
         }
 
 
+@pytest.mark.django_db
+class TestActiveCount:
+
+    def test_host_active_count(self, organization):
+        inv1 = Inventory.objects.create(name='inv1', organization=organization)
+        inv2 = Inventory.objects.create(name='inv2', organization=organization)
+        assert Host.objects.active_count() == 0
+        inv1.hosts.create(name='host1')
+        inv2.hosts.create(name='host1')
+        assert Host.objects.active_count() == 1
+        inv1.hosts.create(name='host2')
+        assert Host.objects.active_count() == 2
+
+    def test_active_count_minus_tower(self, inventory):
+        inventory.hosts.create(name='locally-managed-host')
+        source = inventory.inventory_sources.create(
+            name='tower-source', source='tower'
+        )
+        source.hosts.create(
+            name='remotely-managed-host', inventory=inventory
+        )
+        assert Host.objects.active_count() == 1
+
+
 @pytest.mark.django_db
 class TestSCMUpdateFeatures: