diff --git a/surveillance/maintenance/check_activity.py b/surveillance/maintenance/check_activity.py
index 1ef44824..e44a870b 100755
--- a/surveillance/maintenance/check_activity.py
+++ b/surveillance/maintenance/check_activity.py
@@ -15,17 +15,17 @@ def pg_stat_ended(curseur):
     """
     curseur.execute(PG_STAT_REQ)
     data = curseur.fetchall()
-    seuil = max([donnee['xact_start'] for donnee in data])
+    seuil = max([donnee['xact_start'] for donnee in data if donnee['xact_start'] is not None])
     while True and seuil:
         curseur.execute(PG_STAT_REQ)
         data = curseur.fetchall()
-        front = min([donnee['xact_start'] for donnee in data])
+        front = min([donnee['xact_start'] for donnee in data if donnee['xact_start'] is not None])
         if front > seuil:
             break
         time.sleep(30)
 
 if __name__ == "__main__":
-    conn = psycopg2.connect(database='filtrage')
+    conn = psycopg2.connect(database='filtrage', user='crans')
     conn.set_session(autocommit=True)
     curseur = conn.cursor(cursor_factory=psycopg2.extras.DictCursor)
     pg_stat_ended(curseur)