Fix O(N) queries on staff semester view

e-valuation · Dec 29, 2022 · 5f339e8 · 5f339e8
1 parent e61b2b1
commit 5f339e8
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Showing 3 changed files with 12 additions and 4 deletions.
diff --git a/evap/evaluation/templatetags/evaluation_filters.py b/evap/evaluation/templatetags/evaluation_filters.py
@@ -74,6 +74,11 @@
 register = Library()
 
 
+@register.filter(name="len")
+def _len(a):
+    return len(a)
+
+
 @register.filter(name="zip")
 def _zip(a, b):
     return zip(a, b)

diff --git a/evap/staff/templates/staff_semester_view.html b/evap/staff/templates/staff_semester_view.html
@@ -384,11 +384,11 @@ <h3>
                                             {{ course.responsibles_names }}
                                         </div>
                                     </td>
-                                    <td data-col="evaluation-count" data-order="{{ course.evaluations.count }}">
-                                        {% if course.evaluations.count == 0 %}
+                                    <td data-col="evaluation-count" data-order="{{ course.evaluations.all|len }}">
+                                        {% if course.evaluations.all|len == 0 %}
                                             <span class="badge bg-warning">{% trans 'No evaluations' %}</span>
                                         {% else %}
-                                            {{ course.evaluations.count }}
+                                            {{ course.evaluations.all|len }}
                                         {% endif %}
                                     </td>
                                     <td class="icon-buttons">

diff --git a/evap/staff/views.py b/evap/staff/views.py
@@ -149,6 +149,7 @@ def get_evaluations_with_prefetched_data(semester):
             ),
             "course__degrees",
             "course__responsibles",
+            "course__semester",
         )
         .annotate(
             num_contributors=Count("contributions", filter=~Q(contributions__contributor=None), distinct=True),
@@ -180,7 +181,9 @@ def semester_view(request, semester_id):
 
     evaluations = get_evaluations_with_prefetched_data(semester)
     evaluations = sorted(evaluations, key=lambda cr: cr.full_name)
-    courses = Course.objects.filter(semester=semester)
+    courses = Course.objects.filter(semester=semester).prefetch_related(
+        "type", "degrees", "responsibles", "evaluations"
+    )
 
     # semester statistics (per degree)
     @dataclass