Dashboard screen performance fix

readthedocs/projects/views/private.py

@@ -7,6 +7,7 @@
 from django.contrib import messages
 from django.contrib.auth.decorators import login_required
 from django.contrib.auth.models import User
+from django.db.models import Count, OuterRef, Subquery
 from django.http import (
     Http404,
     HttpResponseBadRequest,
@@ -23,7 +24,7 @@
 from vanilla import CreateView, DeleteView, DetailView, GenericView, UpdateView
 
 from readthedocs.builds.forms import VersionForm
-from readthedocs.builds.models import Version
+from readthedocs.builds.models import Build, Version
 from readthedocs.core.mixins import ListViewWithForm, LoginRequiredMixin
 from readthedocs.core.utils import broadcast, prepare_build, trigger_build
 from readthedocs.integrations.models import HttpExchange, Integration
@@ -92,7 +93,14 @@ def validate_primary_email(self, user):
             notification.send()
 
     def get_queryset(self):
-        return Project.objects.dashboard(self.request.user)
+        # Filters the builds for a perticular project.
+        builds = Build.objects.filter(
+            project=OuterRef('pk'), type='html', state='finished')
+        # Creates a Subquery object which returns
+        # the value of Build.success of the latest build.
+        sub_query = Subquery(builds.values('success')[:1])
+        return Project.objects.dashboard(self.request.user).annotate(
+            build_count=Count('builds'), latest_build_success=sub_query)
 
     def get(self, request, *args, **kwargs):
         self.validate_primary_email(request.user)

readthedocs/templates/projects/project_dashboard_base.html

@@ -66,7 +66,7 @@ <h3>{% trans "Projects" %}</h3>
                       {% block project-name %}
                         {{ project.name }}
                       {% endblock %}
-                      {% with builds=project.builds.count %}
+                      {% with builds=project.build_count %}
                         {% if builds == 0 %}
                           <span class="right quiet">
                             {% trans "No builds yet" %}
@@ -80,13 +80,11 @@ <h3>{% trans "Projects" %}</h3>
                                 {{ builds }} builds
                               {% endblocktrans %}
                             </span>
-                            {% with build=project.get_latest_build %}
-                              {% if build.success %}
-                                <span class="build-state build-state-passing">{% trans "passing" %}</span>
-                              {% else %}
-                                <span class="build-state build-state-failing">{% trans "failing" %}</span>
-                              {% endif %}
-                            {% endwith %}
+                            {% if project.latest_build_success %}
+                              <span class="build-state build-state-passing">{% trans "passing" %}</span>
+                            {% else %}
+                              <span class="build-state build-state-failing">{% trans "failing" %}</span>
+                            {% endif %}
                           </span>
                         {% endif %}
                       {% endwith %}