identity map->weakvaluedictionary

diff --git a/lib/sqlalchemy/mapping/objectstore.py b/lib/sqlalchemy/mapping/objectstore.py
index 7b5ebe82e45e31bc3fbfc6393e1edb5b3fe597df..5ca78b6f4b375ad924cfd494e19dd84bc92e9718 100644 (file)
--- a/lib/sqlalchemy/mapping/objectstore.py
+++ b/lib/sqlalchemy/mapping/objectstore.py
@@ -146,7 +146,7 @@ class UnitOfWork(object):
         if parent is not None:
             self.identity_map = parent.identity_map
         else:
-            self.identity_map = {}
+            self.identity_map = weakref.WeakValueDictionary()
             
         self.attributes = global_attributes
         self.new = util.HashSet(ordered = True)