diff --git a/swh/storage/db.py b/swh/storage/db.py
--- a/swh/storage/db.py
+++ b/swh/storage/db.py
@@ -987,6 +987,7 @@
                        ON ov.origin = ovs.origin AND ov.visit = ovs.visit
                      INNER JOIN snapshot ON ovs.snapshot=snapshot.id
                      WHERE ov.origin=o.id
+                     LIMIT 1
                      )
                    AND """
         query += "url %s %%s "