Optimize collection_viva by aggressively prefetching and annotating related objects to prevent N+1 queries

atlas/models.py

@@ -720,11 +720,20 @@ class Case(models.Model, AuthorMixin, QuestionMixin):
 
         series_qs = self.series.all()
         if exclude_series_ids is not None:
-            series_qs = self.series.exclude(id__in=exclude_series_ids)
-        images = [
-            [image.image.url for image in series.images.filter(removed=False)]
-            for series in series_qs.order_by('seriesdetail__sort_order').prefetch_related('images')
-        ]
+            series_qs = series_qs.exclude(id__in=exclude_series_ids)
+
+        # Ensure series are ordered by the through model sort_order
+        series_list = list(series_qs.order_by('seriesdetail__sort_order').prefetch_related('images'))
+
+        images = []
+        for series in series_list:
+            # If images were prefetched, use the cached list and filter in Python
+            prefetched = getattr(series, '_prefetched_objects_cache', {}).get('images')
+            if prefetched is not None:
+                imgs = [img.image.url for img in prefetched if not getattr(img, 'removed', False)]
+            else:
+                imgs = [image.image.url for image in series.images.filter(removed=False)]
+            images.append(imgs)
 
         if as_json:
             return json.dumps(images)