Using generators for small lists is highly inefficient. This change shoves

6% of total time for large ORM queries. Not bad for a 2 characters change :)

diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 6bc55c831526de86c66ed7a9e421574d18d220b3..146c4d67373bf3f75ec357463f5a9c0f0cf126d7 100644 (file)
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -1583,7 +1583,7 @@ class Mapper(object):
 
         identity_class = self._identity_class
         def identity_key(row):
-            return (identity_class, tuple(row[column] for column in pk_cols))
+            return (identity_class, tuple([row[column] for column in pk_cols]))
 
         new_populators = []
         existing_populators = []