def get_queryset(self, *args, **kwargs):
return prefetch_generic_foreign_key_objects(
super()
.get_queryset()
.select_related("user", "content_type")
.order_by("content_type")
)
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
# Prefetch the object list here as at this point it has been paginated
# which saves prefetching the related objects for all notifications
context["object_list"] = prefetch_generic_foreign_key_objects(
context["object_list"])
return context
def test_notification_list_view_num_queries(client, django_assert_num_queries):
user1 = UserFactory()
phase = PhaseFactory()
eval = EvaluationFactory(submission__phase=phase,
status=Evaluation.FAILURE)
# delete all prior notifications for easier testing below
Notification.objects.all().delete()
# create notification
_ = NotificationFactory(
user=user1,
type=Notification.Type.EVALUATION_STATUS,
actor=eval.submission.creator,
message="failed",
action_object=eval,
target=phase,
)
notifications = Notification.objects.select_related(
"actor_content_type",
"target_content_type",
"action_object_content_type",
"user",
).all()
notifications_with_prefetched_fks = prefetch_generic_foreign_key_objects(
Notification.objects.select_related(
"actor_content_type",
"target_content_type",
"action_object_content_type",
"user",
).all())
try:
settings.DEBUG = True
notifications[0].target
# when the generic foreign keys have not been prefetched, accessing the
# action target, result in two db calls
assert len(connection.queries) == 2
reset_queries()
notifications_with_prefetched_fks[0].target
# when gfks have been prefetched, accessing the action target
# no longer requires any db calls
assert len(connection.queries) == 0
# related objects of the generic foreign keys have also been prefetched
notifications[0].action_object.submission.phase.challenge
assert len(connection.queries) == 5
reset_queries()
notifications_with_prefetched_fks[
0].action_object.submission.phase.challenge
assert len(connection.queries) == 0
finally:
settings.DEBUG = False
reset_queries()
def get_queryset(self):
return prefetch_generic_foreign_key_objects(
super()
.get_queryset()
.select_related(
"actor_content_type",
"target_content_type",
"action_object_content_type",
"user__verification",
)
.order_by("-created")
)
def test_follow_list_view_num_queries():
user1 = UserFactory()
f = ForumFactory(type=Forum.FORUM_POST)
follow(user=user1, obj=f)
follows = Follow.objects.select_related("user", "content_type").all()
follows_with_prefetched_gfks = prefetch_generic_foreign_key_objects(
Follow.objects.select_related("user", "content_type").all())
try:
settings.DEBUG = True
follows[0].follow_object
assert len(connection.queries) == 2
reset_queries()
follows_with_prefetched_gfks[0].follow_object
assert len(connection.queries) == 0
finally:
settings.DEBUG = False
reset_queries()
def test_notification_list_view_num_queries(client, django_assert_num_queries):
user1 = UserFactory()
_ = NotificationFactory(
user=user1,
message="requested access to",
target=AlgorithmFactory(),
type=Notification.Type.ACCESS_REQUEST,
)
notifications = Notification.objects.select_related(
"actor_content_type",
"target_content_type",
"action_object_content_type",
"user",
).all()
notifications_with_prefetched_fks = prefetch_generic_foreign_key_objects(
Notification.objects.select_related(
"actor_content_type",
"target_content_type",
"action_object_content_type",
"user",
).all())
# double check that there is an action target for the test below to be meaningful
assert notifications[0].target
try:
settings.DEBUG = True
notifications[0].target
# when the generic foreign keys have not been prefetched, accessing the
# action target, result in two db calls
assert len(connection.queries) == 2
reset_queries()
notifications_with_prefetched_fks[0].target
# when gfks have been prefetched, accessing the action target
# no longer requires any db calls
assert len(connection.queries) == 0
finally:
settings.DEBUG = False
reset_queries()
