Improve park listing performance with optimized queries and caching

Implement performance enhancements for park listing by optimizing database queries, introducing efficient caching mechanisms, and refining pagination for a significantly faster and smoother user experience.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: c446bc9e-66df-438c-a86c-f53e6da13649
Replit-Commit-Checkpoint-Type: intermediate_checkpoint

apps/parks/views.py

@@ -229,10 +229,16 @@ class ParkListView(HTMXFilterableMixin, ListView):
     context_object_name = "parks"
     filter_class = ParkFilter
     paginate_by = 20
+    
+    # Use optimized pagination
+    paginator_class = None  # Will be set dynamically
 
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
         self.filter_service = ParkFilterService()
+        # Import here to avoid circular imports
+        from .services.pagination_service import OptimizedPaginator
+        self.paginator_class = OptimizedPaginator
 
     def get_template_names(self) -> list[str]:
         """Return park_list.html for HTMX requests"""
@@ -246,54 +252,35 @@ class ParkListView(HTMXFilterableMixin, ListView):
 
     def get_queryset(self) -> QuerySet[Park]:
         """Get optimized queryset with enhanced filtering and proper relations"""
+        from apps.core.utils.query_optimization import monitor_db_performance
+        
         try:
-            # Start with optimized base queryset
-            queryset = (
-                get_base_park_queryset()
-                .select_related(
-                    'operator',
-                    'property_owner', 
-                    'location',
-                    'banner_image',
-                    'card_image'
-                )
-                .prefetch_related(
-                    'photos',
-                    'rides__manufacturer',
-                    'areas'
-                )
-            )
-
-            # Use filter service for enhanced filtering
-            filter_params = self._get_clean_filter_params()
-            
-            # Apply ordering
-            ordering = self.request.GET.get('ordering', 'name')
-            if ordering:
-                # Validate ordering to prevent SQL injection
-                valid_orderings = [
-                    'name', '-name', 
-                    'average_rating', '-average_rating',
-                    'coaster_count', '-coaster_count', 
-                    'ride_count', '-ride_count',
-                    'opening_date', '-opening_date'
-                ]
-                if ordering in valid_orderings:
-                    queryset = queryset.order_by(ordering)
-                else:
-                    queryset = queryset.order_by('name')  # Default fallback
-            
-            # Apply other filters through service
-            filtered_queryset = self.filter_service.get_filtered_queryset(filter_params)
-            
-            # Combine with optimized queryset maintaining the optimizations
-            final_queryset = queryset.filter(
-                pk__in=filtered_queryset.values_list('pk', flat=True)
-            )
-
-            # Create filterset for form rendering
-            self.filterset = self.filter_class(self.request.GET, queryset=final_queryset)
-            return self.filterset.qs
+            with monitor_db_performance("park_list_queryset"):
+                # Get clean filter parameters
+                filter_params = self._get_clean_filter_params()
+                
+                # Use filter service to build optimized queryset directly
+                # This eliminates the expensive pk__in subquery anti-pattern
+                queryset = self.filter_service.get_optimized_filtered_queryset(filter_params)
+                
+                # Apply ordering with validation
+                ordering = self.request.GET.get('ordering', 'name')
+                if ordering:
+                    valid_orderings = [
+                        'name', '-name', 
+                        'average_rating', '-average_rating',
+                        'coaster_count', '-coaster_count', 
+                        'ride_count', '-ride_count',
+                        'opening_date', '-opening_date'
+                    ]
+                    if ordering in valid_orderings:
+                        queryset = queryset.order_by(ordering)
+                    else:
+                        queryset = queryset.order_by('name')  # Default fallback
+                
+                # Create filterset for form rendering
+                self.filterset = self.filter_class(self.request.GET, queryset=queryset)
+                return self.filterset.qs
             
         except Exception as e:
             messages.error(self.request, f"Error loading parks: {str(e)}")