perf: N+1 fixes

openedx · Sep 20, 2023 · 637416d · 637416d
1 parent e279ca3
commit 637416d
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Showing 2 changed files with 15 additions and 4 deletions.
diff --git a/course_discovery/apps/api/serializers.py b/course_discovery/apps/api/serializers.py
@@ -1023,10 +1023,17 @@ class CourseRunSerializer(MinimalCourseRunSerializer):
     def prefetch_queryset(cls, queryset=None):
         queryset = super().prefetch_queryset(queryset=queryset)
 
-        return queryset.select_related('language', 'video', 'expected_program_type').prefetch_related(
+        return queryset.select_related(
             'course__level_type',
+            'course__video__image',
+            'language',
+            'video',
+            'expected_program_type'
+        ).prefetch_related(
+            'course__level_type__translations',
             'transcript_languages',
             'video__image',
+            'language__translations',
             Prefetch('staff', queryset=MinimalPersonSerializer.prefetch_queryset()),
         )
 
@@ -1100,7 +1107,11 @@ class CourseRunWithProgramsSerializer(CourseRunSerializer):
     def prefetch_queryset(cls, queryset=None):
         queryset = super().prefetch_queryset(queryset=queryset)
 
-        return queryset.prefetch_related('course__programs__excluded_course_runs')
+        return queryset.select_related('course').prefetch_related(
+            Prefetch('course__programs', queryset=(
+                Program.objects.select_related('type', 'partner').prefetch_related('excluded_course_runs', 'courses')
+            ))
+        )
 
     def get_programs(self, obj):
         programs = []

diff --git a/course_discovery/apps/api/v1/tests/test_views/test_course_runs.py b/course_discovery/apps/api/v1/tests/test_views/test_course_runs.py
@@ -1019,7 +1019,7 @@ def test_list(self):
         """ Verify the endpoint returns a list of all course runs. """
         url = reverse('api:v1:course_run-list')
 
-        with self.assertNumQueries(17, threshold=3):
+        with self.assertNumQueries(14, threshold=3):
             response = self.client.get(url)
 
         assert response.status_code == 200
@@ -1032,7 +1032,7 @@ def test_list_sorted_by_course_start_date(self):
         """ Verify the endpoint returns a list of all course runs sorted by start date. """
         url = '{root}?ordering=start'.format(root=reverse('api:v1:course_run-list'))
 
-        with self.assertNumQueries(17, threshold=3):
+        with self.assertNumQueries(14, threshold=3):
             response = self.client.get(url)
 
         assert response.status_code == 200