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)

atlas/views.py

@@ -3111,31 +3111,32 @@ def collection_viva(request, pk):
     #    )
     #)
 
+    # Prefetch and annotate aggressively to avoid N+1 queries in the viva view.
+    # - Prefetch `case__series` using the ordering from SeriesDetail
+    # - Prefetch only non-removed images for those series (ordered by position)
+    # - Prefetch case resources and display sets
+    from django.db.models import Prefetch as _Prefetch
+
+    series_images_qs = SeriesImage.objects.filter(removed=False).order_by("position")
+    series_qs = Series.objects.order_by("seriesdetail__sort_order").prefetch_related(
+        _Prefetch("images", queryset=series_images_qs)
+    )
+
     casedetails = (
         CaseDetail.objects
         .filter(collection=collection)
         .select_related("case")
         .order_by("sort_order")
         .prefetch_related(
-            # Prefetch series and their images directly on the case
-            "case__series",
-            "case__series__modality",
-            "case__series__examination",
-            "case__series__plane",
-            "case__series__contrast",
-            "case__series__images",
+            _Prefetch("case__series", queryset=series_qs),
+            _Prefetch("case__series__modality"),
+            _Prefetch("case__series__examination"),
+            _Prefetch("case__series__plane"),
+            _Prefetch("case__series__contrast"),
+            _Prefetch("case__caseresource_set"),
+            _Prefetch("case__display_sets"),
         )
-    )
-
-    # Also annotate and prefetch additional related objects used by the viva
-    # template to avoid N+1 queries when rendering many cases.
-    casedetails = (
-        casedetails
         .annotate(series_count=Count("case__seriesdetail"))
-        .prefetch_related(
-            "case__caseresource_set",
-            "case__display_sets",
-        )
     )