Limit batch size in bulk voucher creation (avoid problems with MySQL's max_packet_size)

src/pretix/control/forms/vouchers.py

@@ -393,7 +393,7 @@ class VoucherBulkForm(VoucherForm):
             data['bulk'] = True
             del data['codes']
             objs.append(obj)
-        Voucher.objects.bulk_create(objs)
+        Voucher.objects.bulk_create(objs, batch_size=200)
         objs = []
         for v in event.vouchers.filter(code__in=self.cleaned_data['codes']):
             # We need to query them again as bulk_create does not fill in .pk values on databases

src/pretix/control/views/vouchers.py

@@ -327,7 +327,7 @@ class VoucherBulkCreate(EventPermissionRequiredMixin, CreateView):
                 v.log_action('pretix.voucher.added', data=form.cleaned_data, user=self.request.user, save=False)
             )
             voucherids.append(v.pk)
-        LogEntry.objects.bulk_create(log_entries)
+        LogEntry.objects.bulk_create(log_entries, batch_size=200)
 
         if form.cleaned_data['send']:
             vouchers_send.apply_async(kwargs={