diff --git a/src/pretix/settings.py b/src/pretix/settings.py
index 969822f63..937be967b 100644
--- a/src/pretix/settings.py
+++ b/src/pretix/settings.py
@@ -87,16 +87,17 @@ CACHES = {
         'LOCATION': 'unique-snowflake',
     }
 }
+REAL_CACHE_USED = False
+SESSION_ENGINE = None
 
 HAS_MEMCACHED = config.has_option('memcached', 'location')
 if HAS_MEMCACHED:
+    REAL_CACHE_USED = True
     CACHES['default'] = {
         'BACKEND': 'django.core.cache.backends.memcached.PyLibMCCache',
         'LOCATION': config.get('memcached', 'location'),
     }
 
-SESSION_ENGINE = "django.contrib.sessions.backends.cached_db"
-
 HAS_REDIS = config.has_option('redis', 'location')
 if HAS_REDIS:
     CACHES['redis'] = {
@@ -108,10 +109,16 @@ if HAS_REDIS:
     }
     if not HAS_MEMCACHED:
         CACHES['default'] = CACHES['redis']
+        REAL_CACHE_USED = True
     if config.getboolean('redis', 'sessions', fallback=False):
         SESSION_ENGINE = "django.contrib.sessions.backends.cache"
         SESSION_CACHE_ALIAS = "redis"
 
+if not SESSION_ENGINE and REAL_CACHE_USED:
+    SESSION_ENGINE = "django.contrib.sessions.backends.cached_db"
+else:
+    SESSION_ENGINE = "django.contrib.sessions.backends.db"
+
 HAS_CELERY = config.has_option('celery', 'broker')
 if HAS_CELERY:
     BROKER_URL = config.get('celery', 'broker')