diff --git a/bin/sql_db.py b/bin/sql_db.py
index 1e88f1b66c7..f3b8c86b64c 100644
--- a/bin/sql_db.py
+++ b/bin/sql_db.py
@@ -71,7 +71,7 @@ class Cursor(object):
 
         @wraps(f)
         def wrapper(self, *args, **kwargs):
-            if not hasattr(self, '_obj'):
+            if self.__closed:
                 raise psycopg2.ProgrammingError('Unable to use the cursor after having closing it')
             return f(self, *args, **kwargs)
         return wrapper
@@ -81,6 +81,7 @@ class Cursor(object):
         self._serialized = serialized
         self._cnx = pool.getconn()
         self._obj = self._cnx.cursor(cursor_factory=psycopg1cursor)
+        self.__closed = False
         self.autocommit(False)
         self.dbname = pool.dbname
 
@@ -89,7 +90,7 @@ class Cursor(object):
             self.__caller = tuple(stack()[2][1:3])
         
     def __del__(self):
-        if hasattr(self, '_obj'):
+        if not self.__closed:
             if tools.config['log_level'] in (netsvc.LOG_DEBUG, netsvc.LOG_DEBUG_RPC):
                 # Oops. 'self' has not been closed explicitly.
                 # The cursor will be deleted by the garbage collector, 
@@ -166,6 +167,7 @@ class Cursor(object):
         # collected as fast as they should). The problem is probably due in
         # part because browse records keep a reference to the cursor.
         del self._obj
+        self.__closed = True
         self._pool.putconn(self._cnx)
     
     @check