Dev dashboard performance improvement

Rather than one query per cell in the arches and repos statistics
tables, we can group these together up front using Django annotations.
This means we only need one query per table.

In my local instance with all of the staging repos imported, this
reduces the total query count on this page from 56 to 26, a rather
marked improvement.

Signed-off-by: Dan McGee <dan@archlinux.org>

2 files changed, 14 insertions, 9 deletions

diff --git a/devel/views.py b/devel/views.py
index 39f28a65..cf0d8ad2 100644
--- a/devel/views.py
+++ b/devel/views.py
@@ -13,7 +13,7 @@ from django.contrib.auth.models import User, Group
 from django.contrib.sites.models import Site
 from django.core.mail import send_mail
 from django.db import transaction
-from django.db.models import F
+from django.db.models import F, Count
 from django.http import Http404
 from django.shortcuts import get_object_or_404
 from django.template import loader, Context
@@ -54,6 +54,11 @@ def index(request):
     signoffs = sorted(get_signoff_groups(user=request.user),
             key=operator.attrgetter('pkgbase'))
 
+    arches = Arch.objects.all().annotate(
+            total_ct=Count('packages'), flagged_ct=Count('packages__flag_date'))
+    repos = Repo.objects.all().annotate(
+            total_ct=Count('packages'), flagged_ct=Count('packages__flag_date'))
+
     maintainers = get_annotated_maintainers()
 
     maintained = PackageRelation.objects.filter(
@@ -70,12 +75,12 @@ def index(request):
 
     page_dict = {
             'todos': todolists,
-            'repos': Repo.objects.all(),
-            'arches': Arch.objects.all(),
+            'arches': arches,
+            'repos': repos,
             'maintainers': maintainers,
             'orphan': orphan,
-            'flagged' : flagged,
-            'todopkgs' : todopkgs,
+            'flagged': flagged,
+            'todopkgs': todopkgs,
             'signoffs': signoffs
     }
 
diff --git a/templates/devel/index.html b/templates/devel/index.html
index a0ccb91f..c67cf277 100644
--- a/templates/devel/index.html
+++ b/templates/devel/index.html
@@ -194,10 +194,10 @@
                     <td>{{ arch.name }}</td>
                     <td><a href="/packages/?arch={{ arch.name }}"
                             title="View all packages for the {{ arch.name }} architecture">
-                            <strong>{{ arch.packages.count }}</strong> packages</a></td>
+                            <strong>{{ arch.total_ct }}</strong> packages</a></td>
                     <td><a href="/packages/?arch={{ arch.name }}&amp;flagged=Flagged"
                             title="View all flagged packages for the {{ arch.name }} architecture">
-                            <strong>{{ arch.packages.flagged.count }}</strong> packages</a></td>
+                            <strong>{{ arch.flagged_ct }}</strong> packages</a></td>
                 </tr>
             {% endfor %}
         </tbody>
@@ -224,10 +224,10 @@
                     <td>{{ repo.name }}</td>
                     <td><a href="/packages/?repo={{ repo.name }}"
                             title="View all packages in the {{ repo.name }} repository">
-                            <strong>{{ repo.packages.count }}</strong> packages</a></td>
+                            <strong>{{ repo.total_ct }}</strong> packages</a></td>
                     <td><a href="/packages/?repo={{ repo.name }}&amp;flagged=Flagged"
                             title="View all flagged packages in the {{ repo.name }} repository">
-                            <strong>{{ repo.packages.flagged.count }}</strong> packages</a></td>
+                            <strong>{{ repo.flagged_ct }}</strong> packages</a></td>
                 </tr>
             {% endfor %}
         </tbody>