diff --git a/src/pretix/base/services/cart.py b/src/pretix/base/services/cart.py
index c19aaa462b..e3367532d8 100644
--- a/src/pretix/base/services/cart.py
+++ b/src/pretix/base/services/cart.py
@@ -1,6 +1,7 @@
 from datetime import datetime, timedelta
 
 from django.conf import settings
+from django.db import transaction
 from django.db.models import Q
 from django.utils.timezone import now
 from django.utils.translation import ugettext_lazy as _
@@ -65,7 +66,7 @@ def _check_date(event: Event) -> None:
         raise CartError(error_messages['ended'])
 
 
-def _add_items(event: Event, items: List[Tuple[str, Optional[str], int]],
+def _add_new_items(event: Event, items: List[Tuple[str, Optional[str], int]],
                cart_id: str, expiry: datetime) -> Optional[str]:
     err = None
 
@@ -145,7 +146,7 @@ def _add_items_to_cart(event: Event, items: List[Tuple[str, Optional[str], int]]
         if not items:
             raise CartError(error_messages['empty'])
 
-        err = _add_items(event, items, cart_id, expiry)
+        err = _add_new_items(event, items, cart_id, expiry)
         _delete_expired(expired)
         if err:
             raise CartError(err)
diff --git a/src/pretix/base/services/orders.py b/src/pretix/base/services/orders.py
index 94abb00fcb..45326cbe3b 100644
--- a/src/pretix/base/services/orders.py
+++ b/src/pretix/base/services/orders.py
@@ -182,21 +182,22 @@ def _perform_order(event: str, payment_provider: str, position_ids: List[str],
         _check_positions(event, dt, positions)
         order = _create_order(event, email, positions, dt, pprov,
                               locale=locale)
-        mail(
-            order.email, _('Your order: %(code)s') % {'code': order.code},
-            'pretixpresale/email/order_placed.txt',
-            {
-                'order': order,
-                'event': event,
-                'url': build_absolute_uri(event, 'presale:event.order', kwargs={
-                    'order': order.code,
-                    'secret': order.secret
-                }),
-                'payment': pprov.order_pending_mail_render(order)
-            },
-            event, locale=order.locale
-        )
-        return order.identity
+
+    mail(
+        order.email, _('Your order: %(code)s') % {'code': order.code},
+        'pretixpresale/email/order_placed.txt',
+        {
+            'order': order,
+            'event': event,
+            'url': build_absolute_uri(event, 'presale:event.order', kwargs={
+                'order': order.code,
+                'secret': order.secret
+            }),
+            'payment': pprov.order_pending_mail_render(order)
+        },
+        event, locale=order.locale
+    )
+    return order.identity
 
 
 def perform_order(event: str, payment_provider: str, positions: List[str],