diff --git a/swh/storage/common.py b/swh/storage/common.py
index 69364b3f1..01285ca70 100644
--- a/swh/storage/common.py
+++ b/swh/storage/common.py
@@ -1,32 +1,38 @@
 # Copyright (C) 2015-2016  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import functools
 
 
 def db_transaction(meth):
     """decorator to execute Storage methods within DB transactions
 
     The decorated method must accept a `cur` keyword argument
     """
     @functools.wraps(meth)
     def _meth(self, *args, **kwargs):
-        with self.db.transaction() as cur:
-            return meth(self, *args, cur=cur, **kwargs)
+        if 'cur' in kwargs and kwargs['cur']:
+            return meth(self, *args, **kwargs)
+        else:
+            with self.db.transaction() as cur:
+                return meth(self, *args, cur=cur, **kwargs)
     return _meth
 
 
 def db_transaction_generator(meth):
     """decorator to execute Storage methods within DB transactions, while
     returning a generator
 
     The decorated method must accept a `cur` keyword argument
 
     """
     @functools.wraps(meth)
     def _meth(self, *args, **kwargs):
-        with self.db.transaction() as cur:
-            yield from meth(self, *args, cur=cur, **kwargs)
+        if 'cur' in kwargs and kwargs['cur']:
+            yield from meth(self, *args, **kwargs)
+        else:
+            with self.db.transaction() as cur:
+                yield from meth(self, *args, cur=cur, **kwargs)
     return _meth