WeakCompositeKey was coded incorrectly and was not weakly referencing anything. However when repaired, the usage within RelationLoader._create_joins() still creates cycles between key elements and the value placed in the dict. In the interests of risk reduction, WCK is now removed and the two caches it was used for are now non-cached. Speed comparisons with one join/eager-heavy web application show no noticeable effect in response time.

3 files changed, 3 insertions, 50 deletions

diff --git a/lib/sqlalchemy/orm/properties.py b/lib/sqlalchemy/orm/properties.py
index 7198cc830..c83e03599 100644
--- a/lib/sqlalchemy/orm/properties.py
+++ b/lib/sqlalchemy/orm/properties.py
@@ -381,7 +381,6 @@ class RelationProperty(StrategizedProperty):
         self.join_depth = join_depth
         self.local_remote_pairs = _local_remote_pairs
         self.extension = extension
-        self.__join_cache = {}
         self.comparator_factory = comparator_factory or RelationProperty.Comparator
         self.comparator = self.comparator_factory(self, None)
         util.set_creation_order(self)
@@ -1004,12 +1003,6 @@ class RelationProperty(StrategizedProperty):
         return self.mapper.common_parent(self.parent)
 
     def _create_joins(self, source_polymorphic=False, source_selectable=None, dest_polymorphic=False, dest_selectable=None, of_type=None):
-        key = util.WeakCompositeKey(source_polymorphic, source_selectable, dest_polymorphic, dest_selectable, of_type)
-        try:
-            return self.__join_cache[key]
-        except KeyError:
-            pass
-
         if source_selectable is None:
             if source_polymorphic and self.parent.with_polymorphic:
                 source_selectable = self.parent._with_polymorphic_selectable
@@ -1076,10 +1069,9 @@ class RelationProperty(StrategizedProperty):
         else:
             target_adapter = None
 
-        self.__join_cache[key] = ret = (primaryjoin, secondaryjoin, 
+        return (primaryjoin, secondaryjoin, 
                 (source_selectable or self.parent.local_table), 
                 (dest_selectable or self.mapper.local_table), secondary, target_adapter)
-        return ret
 
     def _get_join(self, parent, primary=True, secondary=True, polymorphic_parent=True):
         """deprecated.  use primary_join_against(), secondary_join_against(), full_join_against()"""
diff --git a/lib/sqlalchemy/orm/strategies.py b/lib/sqlalchemy/orm/strategies.py
index 5f820565f..7195310cd 100644
--- a/lib/sqlalchemy/orm/strategies.py
+++ b/lib/sqlalchemy/orm/strategies.py
@@ -594,7 +594,6 @@ class EagerLoader(AbstractRelationLoader):
     
     def init(self):
         super(EagerLoader, self).init()
-        self.clauses = {}
         self.join_depth = self.parent_property.join_depth
 
     def init_class_attribute(self):
@@ -669,14 +668,8 @@ class EagerLoader(AbstractRelationLoader):
     
         towrap = context.eager_joins.setdefault(entity_key, default_towrap)
     
-        # create AliasedClauses object to build up the eager query.  this is cached after 1st creation.
-        # this also allows ORMJoin to cache the aliased joins it produces since we pass the same
-        # args each time in the typical case.
-        path_key = util.WeakCompositeKey(*path)
-        try:
-            clauses = self.clauses[path_key]
-        except KeyError:
-            self.clauses[path_key] = clauses = mapperutil.ORMAdapter(mapperutil.AliasedClass(self.mapper), 
+        # create AliasedClauses object to build up the eager query.  
+        clauses = mapperutil.ORMAdapter(mapperutil.AliasedClass(self.mapper), 
                     equivalents=self.mapper._equivalent_columns)
 
         if adapter:
diff --git a/lib/sqlalchemy/util.py b/lib/sqlalchemy/util.py
index 619888135..110ef21d5 100644
--- a/lib/sqlalchemy/util.py
+++ b/lib/sqlalchemy/util.py
@@ -1178,38 +1178,6 @@ class _TLocalRegistry(ScopedRegistry):
         except AttributeError:
             pass
 
-class WeakCompositeKey(object):
-    """an weak-referencable, hashable collection which is strongly referenced
-    until any one of its members is garbage collected.
-
-    """
-    keys = set()
-
-    __slots__ = 'args', '__weakref__'
-    
-    def __init__(self, *args):
-        self.args = [self.__ref(arg) for arg in args]
-        WeakCompositeKey.keys.add(self)
-
-    def __ref(self, arg):
-        if isinstance(arg, type):
-            return weakref.ref(arg, self.__remover)
-        else:
-            return lambda: arg
-
-    def __remover(self, wr):
-        WeakCompositeKey.keys.discard(self)
-
-    def __hash__(self):
-        return hash(tuple(self))
-
-    def __cmp__(self, other):
-        return cmp(tuple(self), tuple(other))
-
-    def __iter__(self):
-        return iter(arg() for arg in self.args)
-
-
 class _symbol(object):
     def __init__(self, name):
         """Construct a new named symbol."""