Further optimizations, improve counting to rely on backend DB

ram/bookshelf/admin.py

@@ -194,6 +194,12 @@ class BookAdmin(SortableAdminBase, admin.ModelAdmin):
         ]
 
         data = []
+
+        # Prefetch related data to avoid N+1 queries
+        queryset = queryset.select_related(
+            'publisher', 'shop'
+        ).prefetch_related('authors', 'tags', 'property__property')
+
         for obj in queryset:
             properties = settings.CSV_SEPARATOR_ALT.join(
                 "{}:{}".format(property.property.name, property.value)
@@ -360,6 +366,12 @@ class CatalogAdmin(SortableAdminBase, admin.ModelAdmin):
         ]
 
         data = []
+
+        # Prefetch related data to avoid N+1 queries
+        queryset = queryset.select_related(
+            'manufacturer', 'shop'
+        ).prefetch_related('scales', 'tags', 'property__property')
+
         for obj in queryset:
             properties = settings.CSV_SEPARATOR_ALT.join(
                 "{}:{}".format(property.property.name, property.value)

ram/consist/admin.py

@@ -122,12 +122,27 @@ class ConsistAdmin(SortableAdminBase, admin.ModelAdmin):
             "Item ID",
         ]
         data = []
+
+        # Prefetch related data to avoid N+1 queries
+        queryset = queryset.select_related(
+            'company', 'scale'
+        ).prefetch_related(
+            'tags',
+            'consist_item__rolling_stock__rolling_class__type'
+        )
+
         for obj in queryset:
+            # Cache the type count to avoid recalculating for each item
+            types = " + ".join(
+                "{}x {}".format(t["count"], t["type"])
+                for t in obj.get_type_count()
+            )
+            # Cache tags to avoid repeated queries
+            tags_str = settings.CSV_SEPARATOR_ALT.join(
+                t.name for t in obj.tags.all()
+            )
+
             for item in obj.consist_item.all():
-                types = " + ".join(
-                    "{}x {}".format(t["count"], t["type"])
-                    for t in obj.get_type_count()
-                )
                 data.append(
                     [
                         obj.uuid,
@@ -139,9 +154,7 @@ class ConsistAdmin(SortableAdminBase, admin.ModelAdmin):
                         obj.scale.scale,
                         obj.era,
                         html.unescape(strip_tags(obj.description)),
-                        settings.CSV_SEPARATOR_ALT.join(
-                            t.name for t in obj.tags.all()
-                        ),
+                        tags_str,
                         obj.length,
                         types,
                         item.rolling_stock.__str__(),

ram/consist/models.py

@@ -48,6 +48,11 @@ class Consist(BaseModel):
     def length(self):
         return self.consist_item.filter(load=False).count()
 
+    @property
+    def loads_count(self):
+        """Count of loads in this consist using database aggregation."""
+        return self.consist_item.filter(load=True).count()
+
     def get_type_count(self):
         return self.consist_item.filter(load=False).annotate(
             type=models.F("rolling_stock__rolling_class__type__type")

ram/portal/templates/consist.html

@@ -142,7 +142,7 @@
                     </tr>
                     <tr>
                       <th scope="row">Composition</th>
-                      <td>{% for t in consist.get_type_count %}{{ t.count }}x {{ t.type }} {{t.category }}{% if not forloop.last %} &raquo; {% endif %}{% endfor %}{% if loads %} | <i class="bi bi-download"></i> {{ loads|length }}x Load{{ loads|pluralize }}{% endif %}</td>
+                      <td>{% for t in consist.get_type_count %}{{ t.count }}x {{ t.type }} {{t.category }}{% if not forloop.last %} &raquo; {% endif %}{% endfor %}{% if loads %} | <i class="bi bi-download"></i> {{ loads_count }}x Load{{ loads|pluralize }}{% endif %}</td>
                     </tr>
                   </tbody>
                 </table>

ram/portal/views.py

@@ -579,6 +579,12 @@ class GetConsist(View):
         except ObjectDoesNotExist:
             raise Http404
 
+        # Get all published rolling stock IDs for efficient filtering
+        published_ids = set(
+            RollingStock.objects.get_published(request.user)
+            .values_list('uuid', flat=True)
+        )
+
         # Fetch consist items with related rolling stock in one query
         consist_items = consist.consist_item.select_related(
             'rolling_stock',
@@ -589,21 +595,17 @@ class GetConsist(View):
             'rolling_stock__scale',
         ).prefetch_related('rolling_stock__image')
 
-        # Filter items and loads
-        data = list(
+        # Filter items and loads efficiently
+        data = [
             item.rolling_stock
             for item in consist_items.filter(load=False)
-            if RollingStock.objects.get_published(request.user)
-            .filter(uuid=item.rolling_stock_id)
-            .exists()
-        )
-        loads = list(
+            if item.rolling_stock.uuid in published_ids
+        ]
+        loads = [
             item.rolling_stock
             for item in consist_items.filter(load=True)
-            if RollingStock.objects.get_published(request.user)
-            .filter(uuid=item.rolling_stock_id)
-            .exists()
-        )
+            if item.rolling_stock.uuid in published_ids
+        ]
 
         paginator = Paginator(data, get_items_per_page())
         data = paginator.get_page(page)
@@ -619,6 +621,7 @@ class GetConsist(View):
                 "consist": consist,
                 "data": data,
                 "loads": loads,
+                "loads_count": len(loads),
                 "page_range": page_range,
             },
         )

ram/roster/admin.py

@@ -273,6 +273,18 @@ class RollingStockAdmin(SortableAdminBase, admin.ModelAdmin):
             "Properties",
         ]
         data = []
+
+        # Prefetch related data to avoid N+1 queries
+        queryset = queryset.select_related(
+            'rolling_class',
+            'rolling_class__type',
+            'rolling_class__company',
+            'manufacturer',
+            'scale',
+            'decoder',
+            'shop'
+        ).prefetch_related('tags', 'property__property')
+
         for obj in queryset:
             properties = settings.CSV_SEPARATOR_ALT.join(
                 "{}:{}".format(property.property.name, property.value)