Merge pull request #1362 from open-zaak/feature/zaken_pagination

optimize list zaken

src/openzaak/components/zaken/api/pagination.py

@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: EUPL-1.2
+# Copyright (C) 2023 Dimpact
+from django.core.paginator import Paginator as DjangoPaginator
+from django.utils.functional import cached_property
+
+from rest_framework.pagination import PageNumberPagination
+
+
+class ZaakPaginator(DjangoPaginator):
+    @cached_property
+    def count(self):
+        """
+        ⚡ restricts values to PK to remove implicit join from SQL query
+        """
+        return self.object_list.values("pk").count()
+
+
+class ZaakPagination(PageNumberPagination):
+    django_paginator_class = ZaakPaginator

src/openzaak/components/zaken/api/viewsets.py

@@ -72,6 +72,7 @@
 )
 from .kanalen import KANAAL_ZAKEN
 from .mixins import ClosedZaakMixin
+from .pagination import ZaakPagination
 from .permissions import ZaakAuthRequired, ZaakNestedAuthRequired
 from .scopes import (
     SCOPE_STATUSSEN_TOEVOEGEN,
@@ -242,7 +243,7 @@ class ZaakViewSet(
     filterset_class = ZaakFilter
     ordering_fields = ("startdatum",)
     lookup_field = "uuid"
-    pagination_class = PageNumberPagination
+    pagination_class = ZaakPagination
 
     permission_classes = (ZaakAuthRequired,)
     required_scopes = {