Event product list: Fix another performance issue for large series

This is a follow-up for #6318, basically the same problem but in a
neighboring query.

Performance comparison for real-world event with 13k subevents:

In [15]: %time get_grouped_items(e, subevent=se, channel=e.organizer.sales_channels.get(identifier="web"))
CPU times: user 49.1 ms, sys: 3.79 ms, total: 52.9 ms
Wall time: 1.12 s
Out[15]: ([<Item: xxx>], True

In [16]: %time get_grouped_items_patched(e, subevent=se, channel=e.organizer.sales_channels.get(identifier="web"))
CPU times: user 30.2 ms, sys: 445 μs, total: 30.6 ms
Wall time: 45.3 ms
Out[16]: ([<Item: xxx>], True)

src/pretix/celery_app.py

@@ -19,55 +19,14 @@
 # You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
 # <https://www.gnu.org/licenses/>.
 #
-import logging
 import os
 
-from celery import Celery, signals
-from django.dispatch import receiver
+from celery import Celery
 
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "pretix.settings")
-logger = logging.getLogger(__name__)
 
 from django.conf import settings
 
 app = Celery('pretix')
 app.config_from_object('django.conf:settings', namespace='CELERY')
 app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)
-
-
-@receiver(signals.before_task_publish)
-def on_before_task_publish(sender, body, exchange, routing_key, headers, properties, declare, retry_policy, **kwargs):
-    from pretix.helpers.logs import local
-
-    trace = getattr(local, 'trace', [])
-    request_id = getattr(local, 'request_id', None)
-    if request_id:
-        trace.append(request_id)
-
-    headers["X-Pretix-Trace"] = " ".join(trace)
-
-
-@receiver(signals.task_received)
-def on_task_received(sender, request, **kwargs):
-    trace = request._request_dict.get("X-Pretix-Trace")
-    if trace:
-        logger.info(f"Task {request.id} has trace {trace}")
-
-
-@receiver(signals.task_prerun)
-def on_task_prerun(sender, task_id, task, **kwargs):
-    from pretix.helpers.logs import local
-
-    if "X-Pretix-Trace" in task.request.headers:
-        local.trace = task.request.headers["X-Pretix-Trace"].split(" ")
-    else:
-        local.trace = []
-    local.trace.append(task_id)
-
-
-@receiver(signals.task_postrun)
-def on_task_postrun(sender, task_id, task, **kwargs):
-    from pretix.helpers.logs import local
-
-    local.request_id = None
-    local.trace = []

src/pretix/helpers/logs.py

@@ -20,7 +20,6 @@
 # <https://www.gnu.org/licenses/>.
 #
 import logging
-import uuid
 
 from django.core.signals import request_finished
 from django.dispatch import receiver
@@ -66,9 +65,7 @@ class RequestIdMiddleware:
                 import sentry_sdk
                 sentry_sdk.set_tag("request_id", request.request_id)
         else:
-            # Web server did not pass a request ID, we still generate one to correlate between django logs and
-            # celery logs
-            local.request_id = request.request_id = str(uuid.uuid4())
+            local.request_id = request.request_id = None
 
         return self.get_response(request)
 

src/pretix/presale/views/event.py

@@ -155,8 +155,8 @@ def get_grouped_items(event, *, channel: SalesChannel, subevent=None, voucher=No
         ).filter(
             variation_q,
             Q(all_sales_channels=True) | Q(limit_sales_channels=channel),
+            Exists(Quota.variations.through.objects.filter(quota__subevent_id=subevent, itemvariation_id=OuterRef("pk"))),
             active=True,
-            quotas__isnull=False,
             subevent_disabled=False
         ).prefetch_related(
             *prefetch_membership_types,