From 6988b225c946c86db7e24507424a2b3fd8dba39a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20P=C3=A9ters?= <fpeters@entrouvert.com>
Date: Tue, 24 Dec 2019 10:14:55 +0100
Subject: [PATCH] manager: reduce number of queries when listing events
 (#38699)

---
 chrono/agendas/models.py                      | 38 ++++++++++++++++++-
 .../manager_events_agenda_month_view.html     | 10 ++---
 .../manager_events_agenda_settings.html       | 12 +++---
 chrono/manager/views.py                       |  9 +++++
 tests/test_agendas.py                         | 27 +++++++++++++
 5 files changed, 84 insertions(+), 12 deletions(-)

diff --git a/chrono/agendas/models.py b/chrono/agendas/models.py
index e4e85007..50ec863b 100644
--- a/chrono/agendas/models.py
+++ b/chrono/agendas/models.py
@@ -20,11 +20,12 @@ import math
 import requests
 import vobject
 
+import django
 from django.conf import settings
 from django.contrib.auth.models import Group
 from django.core.exceptions import ValidationError
 from django.db import models, transaction
-from django.db.models import Q
+from django.db.models import Count, Q, Case, When
 from django.urls import reverse
 from django.utils.dates import WEEKDAYS
 from django.utils.encoding import force_text
@@ -358,6 +359,41 @@ class Event(models.Model):
             return False
         return True
 
+    @staticmethod
+    def annotate_queryset(qs):
+        if django.VERSION < (2, 0):
+            return qs.annotate(
+                booked_places_count=Count(
+                    Case(
+                        When(
+                            booking__cancellation_datetime__isnull=True,
+                            booking__in_waiting_list=False,
+                            then='booking',
+                        )
+                    )
+                ),
+                waiting_list_count=Count(
+                    Case(
+                        When(
+                            booking__cancellation_datetime__isnull=True,
+                            booking__in_waiting_list=True,
+                            then='booking',
+                        )
+                    )
+                ),
+            )
+        else:
+            return qs.annotate(
+                booked_places_count=Count(
+                    'booking',
+                    filter=Q(booking__cancellation_datetime__isnull=True, booking__in_waiting_list=False),
+                ),
+                waiting_list_count=Count(
+                    'booking',
+                    filter=Q(booking__cancellation_datetime__isnull=True, booking__in_waiting_list=True),
+                ),
+            )
+
     @property
     def booked_places(self):
         return self.booking_set.filter(cancellation_datetime__isnull=True, in_waiting_list=False).count()
diff --git a/chrono/manager/templates/chrono/manager_events_agenda_month_view.html b/chrono/manager/templates/chrono/manager_events_agenda_month_view.html
index a64e7ad4..f419a937 100644
--- a/chrono/manager/templates/chrono/manager_events_agenda_month_view.html
+++ b/chrono/manager/templates/chrono/manager_events_agenda_month_view.html
@@ -8,13 +8,13 @@
 {% if object_list %}
   <ul class="objects-list single-links">
   {% for event in object_list %}
-    <li class="{% if event.booked_places > event.places %}overbooking{% endif %}
+    <li class="{% if event.booked_places_count > event.places %}overbooking{% endif %}
                {% if event.full %}full{% endif %}
                {% if not event.in_bookable_period %}not-{% endif %}bookable"
         {% if event.places %}
-          data-total="{{event.places}}" data-booked="{{event.booked_places}}"
+          data-total="{{event.places}}" data-booked="{{event.booked_places_count}}"
         {% elif event.waiting_list_places %}
-          data-total="{{event.waiting_list_places}}" data-booked="{{event.waiting_list}}"
+          data-total="{{event.waiting_list_places}}" data-booked="{{event.waiting_list_count}}"
         {% endif %}
         ><a href="{% url 'chrono-manager-event-view' pk=agenda.id event_pk=event.id %}">
         {% if event.label %}{{event.label}} / {% endif %}
@@ -22,11 +22,11 @@
         {% if event.full %}/ <span class="full">{% trans "full" %}</span>{% endif %}
         (
         {% if event.places %}
-        {% blocktrans with places=event.places booked_places=event.booked_places %}{{ places }} places, {{ booked_places }} booked places{% endblocktrans %}
+        {% blocktrans with places=event.places booked_places=event.booked_places_count %}{{ places }} places, {{ booked_places }} booked places{% endblocktrans %}
         {% endif %}
         {% if event.places and event.waiting_list_places %} / {% endif %}
         {% if event.waiting_list_places %}
-        {% blocktrans with places=event.waiting_list_places waiting_places=event.waiting_list %}
+        {% blocktrans with places=event.waiting_list_places waiting_places=event.waiting_list_count %}
         {{waiting_places}} on {{ places }} in waiting list
         {% endblocktrans %}
         {% endif %}
diff --git a/chrono/manager/templates/chrono/manager_events_agenda_settings.html b/chrono/manager/templates/chrono/manager_events_agenda_settings.html
index 51461e6b..a541a3db 100644
--- a/chrono/manager/templates/chrono/manager_events_agenda_settings.html
+++ b/chrono/manager/templates/chrono/manager_events_agenda_settings.html
@@ -13,14 +13,14 @@
 <div>
 {% if object.event_set.count %}
   <ul class="objects-list single-links">
-    {% for event in object.event_set.all %}
-    <li class="{% if event.booked_places > event.places %}overbooking{% endif %}
+    {% for event in view.get_events %}
+    <li class="{% if event.booked_places_count > event.places %}overbooking{% endif %}
                {% if event.full %}full{% endif %}
                {% if not event.in_bookable_period %}not-{% endif %}bookable"
         {% if event.places %}
-          data-total="{{event.places}}" data-booked="{{event.booked_places}}"
+          data-total="{{event.places}}" data-booked="{{event.booked_places_count}}"
         {% elif event.waiting_list_places %}
-          data-total="{{event.waiting_list_places}}" data-booked="{{event.waiting_list}}"
+          data-total="{{event.waiting_list_places}}" data-booked="{{event.waiting_list_count}}"
         {% endif %}
         ><a rel="popup" href="{% url 'chrono-manager-event-edit' pk=agenda.id event_pk=event.id %}?next=settings">
         {% if event.label %}{{event.label}} / {% endif %}
@@ -28,11 +28,11 @@
         {% if event.full %}/ <span class="full">{% trans "full" %}</span>{% endif %}
         (
         {% if event.places %}
-        {% blocktrans with places=event.places booked_places=event.booked_places %}{{ places }} places, {{ booked_places }} booked places{% endblocktrans %}
+        {% blocktrans with places=event.places booked_places=event.booked_places_count %}{{ places }} places, {{ booked_places }} booked places{% endblocktrans %}
         {% endif %}
         {% if event.places and event.waiting_list_places %} / {% endif %}
         {% if event.waiting_list_places %}
-        {% blocktrans with places=event.waiting_list_places waiting_places=event.waiting_list %}
+        {% blocktrans with places=event.waiting_list_places waiting_places=event.waiting_list_count %}
         {{waiting_places}} on {{ places }} in waiting list
         {% endblocktrans %}
         {% endif %}
diff --git a/chrono/manager/views.py b/chrono/manager/views.py
index 41dc9893..d73416d2 100644
--- a/chrono/manager/views.py
+++ b/chrono/manager/views.py
@@ -420,6 +420,12 @@ agenda_day_view = AgendaDayView.as_view()
 
 
 class AgendaMonthView(AgendaDateView, MonthArchiveView):
+    def get_queryset(self):
+        qs = super(AgendaMonthView, self).get_queryset()
+        if self.agenda.kind == 'meetings':
+            return qs
+        return Event.annotate_queryset(qs)
+
     def get_template_names(self):
         return ['chrono/manager_%s_agenda_month_view.html' % self.agenda.kind]
 
@@ -621,6 +627,9 @@ class ManagedDeskSubobjectMixin(object):
 class AgendaSettings(ManagedAgendaMixin, DetailView):
     model = Agenda
 
+    def get_events(self):
+        return Event.annotate_queryset(Event.objects.filter(agenda=self.agenda).select_related('agenda'))
+
     def get_template_names(self):
         return ['chrono/manager_%s_agenda_settings.html' % self.agenda.kind]
 
diff --git a/tests/test_agendas.py b/tests/test_agendas.py
index 1a74bd7b..8b57585d 100644
--- a/tests/test_agendas.py
+++ b/tests/test_agendas.py
@@ -455,3 +455,30 @@ def test_management_role_deletion():
 
     Agenda.objects.get(id=agenda.id).view_role is None
     Agenda.objects.get(id=agenda.id).edit_role is None
+
+
+def test_event_bookings_annotation():
+    agenda = Agenda(label='test', kind='events')
+    agenda.save()
+    event = Event(start_datetime=now(), label='foo', places=10, waiting_list_places=10, agenda=agenda)
+    event.save()
+    event2 = Event(start_datetime=now(), label='bar', places=10, waiting_list_places=10, agenda=agenda)
+    event2.save()
+
+    Booking(event=event).save()
+    Booking(event=event).save()
+    Booking(event=event, cancellation_datetime=now()).save()
+    Booking(event=event, in_waiting_list=True).save()
+    Booking(event=event, in_waiting_list=True, cancellation_datetime=now()).save()
+
+    Booking(event=event2).save()
+    Booking(event=event2).save()
+    Booking(event=event2).save()
+
+    for event in Event.annotate_queryset(Event.objects.filter(agenda=agenda)):
+        if event.label == 'foo':
+            assert event.booked_places_count == 2
+            assert event.waiting_list_count == 1
+        elif event.label == 'bar':
+            assert event.booked_places_count == 3
+            assert event.waiting_list_count == 0