New attempt at improving CheckinList.checkin_count

src/pretix/base/models/checkin.py

@@ -3,7 +3,7 @@ from django.db import models
 from django.db.models import Exists, F, Max, OuterRef, Q, Subquery
 from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _, pgettext_lazy
-from django_scopes import ScopedManager
+from django_scopes import ScopedManager, scopes_disabled
 from jsonfallback.fields import FallbackJSONField
 
 from pretix.base.models import LoggedModel
@@ -90,6 +90,9 @@ class CheckinList(LoggedModel):
         ).count()
 
     @property
+    @scopes_disabled()
+    # Disable scopes, because this query is safe and the additional organizer filter in the EXISTS() subquery tricks PostgreSQL into a bad
+    # subplan that sequentially scans all events
     def checkin_count(self):
         return self.event.cache.get_or_set(
             'checkin_list_{}_checkin_count'.format(self.pk),