Some optimizations to trade_offers to reduce loading times

home/views.py

@@ -14,106 +14,58 @@ from django.http import HttpResponseRedirect
 class HomePageView(TemplateView):
     template_name = "home/home.html"
 
-    def get_base_trade_offer_queryset(self):
-        """
-        Returns a queryset for TradeOffer that includes prefetches and denormalized aggregates.
-        """
-        active_states = [
-            TradeAcceptance.AcceptanceState.ACCEPTED,
-            TradeAcceptance.AcceptanceState.SENT,
-            TradeAcceptance.AcceptanceState.RECEIVED,
-            TradeAcceptance.AcceptanceState.THANKED_BY_INITIATOR,
-            TradeAcceptance.AcceptanceState.THANKED_BY_ACCEPTOR,
-            TradeAcceptance.AcceptanceState.THANKED_BY_BOTH,
-        ]
-
-        have_cards_prefetch = Prefetch(
-            'have_cards',
-            queryset=Card.objects.annotate(
-                trade_offer_count=Count("trade_offers_have")
-            ).order_by("trade_offer_count", "id")
-        )
-        want_cards_prefetch = Prefetch(
-            'want_cards',
-            queryset=Card.objects.annotate(
-                trade_offer_count=Count("trade_offers_want")
-            ).order_by("trade_offer_count", "id")
-        )
-
-        qs = (
-            TradeOffer.objects.all()
-            .prefetch_related(
-                have_cards_prefetch,
-                "have_cards__decks",
-                "have_cards__rarity",
-                "have_cards__cardset",
-                want_cards_prefetch,
-                "want_cards__decks",
-                "want_cards__rarity",
-                "want_cards__cardset",
-                "acceptances",
-                
-            )
-            .select_related("initiated_by__user")
-        )
-        return qs
-
     def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)
         
-        context["cards"] = Card.objects.all() \
-            .order_by("name", "rarity__pk") \
-            .select_related("rarity", "cardset") \
-            .prefetch_related("decks")
+        context["cards"] = Card.objects.all().order_by("name", "rarity__pk")
         
         # Reuse base trade offer queryset for market stats
-        base_offer_qs = self.get_base_trade_offer_queryset().filter(is_closed=False)
+        base_offer_qs = TradeOffer.objects.filter(is_closed=False)
         
         # Recent Offers
-        recent_offers_qs = base_offer_qs.order_by("-created_at")[:10]
-        context["recent_offers"] = list(recent_offers_qs)[:5]
+        recent_offers_qs = base_offer_qs.order_by("-created_at")
+        context["recent_offers"] = recent_offers_qs[:6]
         
         # Most Offered Cards
         context["most_offered_cards"] = (
-            Card.objects.filter(tradeofferhavecard__isnull=False)
+            Card.objects_no_prefetch.filter(tradeofferhavecard__isnull=False)
             .annotate(offer_count=Sum("tradeofferhavecard__quantity"))
-            .order_by("-offer_count")
-            .select_related("rarity", "cardset")
-            .prefetch_related("decks")[:5]
+            .order_by("-offer_count", "?")[:6]
         )
         
         # Most Wanted Cards
         context["most_wanted_cards"] = (
-            Card.objects.filter(tradeofferwantcard__isnull=False)
+            Card.objects_no_prefetch.filter(tradeofferwantcard__isnull=False)
             .annotate(offer_count=Sum("tradeofferwantcard__quantity"))
-            .order_by("-offer_count")
-            .select_related("rarity", "cardset")
-            .prefetch_related("decks")[:5]
+            .order_by("-offer_count", "?")[:6]
         )
         
         # Least Offered Cards
         context["least_offered_cards"] = (
-            Card.objects.annotate(offer_count=Sum("tradeofferhavecard__quantity"))
-            .order_by("offer_count", "?")[:5]
+            Card.objects_no_prefetch.annotate(offer_count=Sum("tradeofferhavecard__quantity"))
+            .order_by("offer_count", "?")[:6]
         )
         
-        # Featured Offers grouped by rarity
-        all_offers = base_offer_qs.order_by("created_at")
         featured = {}
-        featured["All"] = all_offers[:5]
-        grouped = defaultdict(list)
-        for offer in all_offers:
-            normalized_ids = {card.rarity.normalized_id for card in offer.have_cards.all() if card.rarity}
-            for norm in normalized_ids:
-                grouped[norm].append(offer)
-        norm_ids_available = list(grouped.keys())
-        rareness_qs = Rarity.objects.filter(pk__in=[6] + [nid for nid in norm_ids_available if nid != 6])
-        rarity_map = {rarity.pk: rarity.icons for rarity in rareness_qs}
-        for norm in sorted(grouped.keys(), reverse=True):
-            offers = grouped[norm]
+        featured["All"] = base_offer_qs.order_by("created_at")[:6]
+
+        normalized_ids = list(
+            Rarity.objects.filter(pk__lte=5).values_list("normalized_id", flat=True).distinct()
+        )
+
+        rarity_map = {rarity.normalized_id: rarity.icons for rarity in Rarity.objects.filter(pk__lte=5)}
+
+        # For each normalized id (sorted descending), filter base offers that have a related card with that rarity.
+        for norm in sorted(normalized_ids, reverse=True):
+            offers_qs = base_offer_qs.filter(
+                have_cards__rarity__normalized_id=norm
+                # or want cards, but all offers share the same rarity so checking have_cards is enough
+                # TODO: attach rarity to offer so we don't need to do this
+            ).order_by("created_at").distinct()[:6]
             icon_label = rarity_map.get(norm)
             if icon_label:
-                featured[icon_label] = offers[:5]
+                featured[icon_label] = offers_qs
+
         context["featured_offers"] = featured
 
         return context