- add MemoizedSlots, a generalized solution to using __getattr__

for memoization on a class that uses slots.
- apply many more __slots__.  mem use for nova now at 46% savings

1 files changed, 14 insertions, 6 deletions

diff --git a/lib/sqlalchemy/orm/properties.py b/lib/sqlalchemy/orm/properties.py
index 291fabdd0..d51b6920d 100644
--- a/lib/sqlalchemy/orm/properties.py
+++ b/lib/sqlalchemy/orm/properties.py
@@ -34,6 +34,13 @@ class ColumnProperty(StrategizedProperty):
 
     strategy_wildcard_key = 'column'
 
+    __slots__ = (
+        '_orig_columns', 'columns', 'group', 'deferred',
+        'instrument', 'comparator_factory', 'descriptor', 'extension',
+        'active_history', 'expire_on_flush', 'info', 'doc',
+        'strategy_class', '_creation_order', '_is_polymorphic_discriminator',
+        '_mapped_by_synonym')
+
     def __init__(self, *columns, **kwargs):
         """Provide a column-level property for use with a Mapper.
 
@@ -109,6 +116,7 @@ class ColumnProperty(StrategizedProperty):
             **Deprecated.** Please see :class:`.AttributeEvents`.
 
         """
+        super(ColumnProperty, self).__init__()
         self._orig_columns = [expression._labeled(c) for c in columns]
         self.columns = [expression._labeled(_orm_full_deannotate(c))
                         for c in columns]
@@ -206,7 +214,7 @@ class ColumnProperty(StrategizedProperty):
         elif dest_state.has_identity and self.key not in dest_dict:
             dest_state._expire_attributes(dest_dict, [self.key])
 
-    class Comparator(PropComparator):
+    class Comparator(util.MemoizedSlots, PropComparator):
         """Produce boolean, comparison, and other operators for
         :class:`.ColumnProperty` attributes.
 
@@ -225,8 +233,9 @@ class ColumnProperty(StrategizedProperty):
 
         """
 
-        @util.memoized_instancemethod
-        def __clause_element__(self):
+        __slots__ = '__clause_element__', 'info'
+
+        def _memoized_method___clause_element__(self):
             if self.adapter:
                 return self.adapter(self.prop.columns[0])
             else:
@@ -234,15 +243,14 @@ class ColumnProperty(StrategizedProperty):
                     "parententity": self._parentmapper,
                     "parentmapper": self._parentmapper})
 
-        @util.memoized_property
-        def info(self):
+        def _memoized_attr_info(self):
             ce = self.__clause_element__()
             try:
                 return ce.info
             except AttributeError:
                 return self.prop.info
 
-        def __getattr__(self, key):
+        def _fallback_getattr(self, key):
             """proxy attribute access down to the mapped column.
 
             this allows user-defined comparison methods to be accessed.