Fix Active Dref Operations List n+1 query issue (active-dref)

Author: szabozoltan69

dref/serializers.py

@@ -252,24 +252,36 @@ class Meta:
 
     @extend_schema_field(MiniOperationalUpdateActiveSerializer(many=True))
     def get_operational_update_details(self, obj):
-        queryset = DrefOperationalUpdate.objects.filter(dref_id=obj.id).order_by("-created_at")
+        prefetched = getattr(obj, "prefetched_operational_updates", None)
+        queryset = prefetched if prefetched is not None else obj.drefoperationalupdate_set.order_by("-created_at")
         return MiniOperationalUpdateActiveSerializer(queryset, many=True).data
 
     @extend_schema_field(MiniDrefFinalReportActiveSerializer)
     def get_final_report_details(self, obj):
-        queryset = DrefFinalReport.objects.filter(dref_id=obj.id).first()
-        return MiniDrefFinalReportActiveSerializer(queryset).data
+        prefetched = getattr(obj, "prefetched_final_report", None)
+        if prefetched is not None:
+            final_report = prefetched[0] if prefetched else None
+        else:
+            try:
+                final_report = obj.dreffinalreport
+            except DrefFinalReport.DoesNotExist:
+                final_report = None
+        return MiniDrefFinalReportActiveSerializer(final_report).data
 
     def get_has_ops_update(self, obj) -> bool:
-        op_count_count = obj.drefoperationalupdate_set.count()
-        if op_count_count > 0:
-            return True
-        return False
+        prefetched = getattr(obj, "prefetched_operational_updates", None)
+        if prefetched is not None:
+            return len(prefetched) > 0
+        return obj.drefoperationalupdate_set.exists()
 
     def get_has_final_report(self, obj) -> bool:
-        if hasattr(obj, "dreffinalreport"):
-            return True
-        return False
+        prefetched = getattr(obj, "prefetched_final_report", None)
+        if prefetched is not None:
+            return bool(prefetched)
+        try:
+            return obj.dreffinalreport is not None
+        except DrefFinalReport.DoesNotExist:
+            return False
 
     def get_application_type(self, obj) -> str:
         return "DREF"
@@ -278,10 +290,23 @@ def get_application_type_display(self, obj) -> str:
         return gettext("DREF application")
 
     def get_unpublished_op_update_count(self, obj) -> int:
+        prefetched = getattr(obj, "prefetched_operational_updates", None)
+        if prefetched is not None:
+            return sum(1 for op in prefetched if op.status != Dref.Status.APPROVED)
         return DrefOperationalUpdate.objects.filter(dref_id=obj.id).exclude(status=Dref.Status.APPROVED).count()
 
     def get_unpublished_final_report_count(self, obj) -> int:
-        return DrefFinalReport.objects.filter(dref_id=obj.id).exclude(status=Dref.Status.APPROVED).count()
+        prefetched = getattr(obj, "prefetched_final_report", None)
+        if prefetched is not None:
+            if not prefetched:
+                return 0
+            final_report = prefetched[0]
+            return 0 if final_report.status == Dref.Status.APPROVED else 1
+        try:
+            final_report = obj.dreffinalreport
+        except DrefFinalReport.DoesNotExist:
+            return 0
+        return 0 if final_report.status == Dref.Status.APPROVED else 1
 
 
 class PlannedInterventionSerializer(

dref/views.py

@@ -5,6 +5,7 @@
 import django.utils.timezone as timezone
 from django.contrib.auth.models import Permission
 from django.db import models, transaction
+from django.db.models import Prefetch
 from django.http import HttpResponse
 from django.templatetags.static import static
 from django.utils.translation import gettext
@@ -345,7 +346,23 @@ class ActiveDrefOperationsViewSet(viewsets.ReadOnlyModelViewSet):
     permission_classes = [permissions.IsAuthenticated, DenyGuestUserPermission]
     filterset_class = ActiveDrefFilterSet
     queryset = (
-        Dref.objects.prefetch_related("planned_interventions", "needs_identified", "national_society_actions", "users")
+        Dref.objects.select_related("country")
+        .prefetch_related(
+            "planned_interventions",
+            "needs_identified",
+            "national_society_actions",
+            "users",
+            Prefetch(
+                "dreffinalreport",
+                queryset=DrefFinalReport.objects.all(),
+                to_attr="prefetched_final_report",
+            ),
+            Prefetch(
+                "drefoperationalupdate_set",
+                queryset=DrefOperationalUpdate.objects.order_by("-created_at"),
+                to_attr="prefetched_operational_updates",
+            ),
+        )
         .order_by("-created_at")
         .filter(is_active=True)
         .distinct()