- Added a new extension suite :mod:`sqlalchemy.ext.baked`. This

simple but unusual system allows for a dramatic savings in Python
overhead for the construction and processing of orm :class:`.Query`
objects, from query construction up through rendering of a string
SQL statement.
fixes #3054

1 files changed, 57 insertions, 30 deletions

diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index c6fdf479e..05349cf0b 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -26,7 +26,7 @@ from . import (
     exc as orm_exc, loading
 )
 from .base import _entity_descriptor, _is_aliased_class, \
-    _is_mapped_class, _orm_columns, _generative
+    _is_mapped_class, _orm_columns, _generative, InspectionAttr
 from .path_registry import PathRegistry
 from .util import (
     AliasedClass, ORMAdapter, join as orm_join, with_parent, aliased
@@ -831,7 +831,9 @@ class Query(object):
         :return: The object instance, or ``None``.
 
         """
+        return self._get_impl(ident, loading.load_on_ident)
 
+    def _get_impl(self, ident, fallback_fn):
         # convert composite types to individual args
         if hasattr(ident, '__composite_values__'):
             ident = ident.__composite_values__()
@@ -862,7 +864,7 @@ class Query(object):
                     return None
                 return instance
 
-        return loading.load_on_ident(self, key)
+        return fallback_fn(self, key)
 
     @_generative()
     def correlate(self, *args):
@@ -3332,7 +3334,7 @@ class _MapperEntity(_QueryEntity):
 
 
 @inspection._self_inspects
-class Bundle(object):
+class Bundle(InspectionAttr):
     """A grouping of SQL expressions that are returned by a :class:`.Query`
     under one namespace.
 
@@ -3528,14 +3530,20 @@ class _ColumnEntity(_QueryEntity):
     def __init__(self, query, column, namespace=None):
         self.expr = column
         self.namespace = namespace
+        search_entities = True
 
         if isinstance(column, util.string_types):
             column = sql.literal_column(column)
             self._label_name = column.name
+            search_entities = False
+            _entity = None
         elif isinstance(column, (
             attributes.QueryableAttribute,
             interfaces.PropComparator
         )):
+            _entity = column._parententity
+            if _entity is not None:
+                search_entities = False
             self._label_name = column.key
             column = column._query_clause_element()
             if isinstance(column, Bundle):
@@ -3558,6 +3566,7 @@ class _ColumnEntity(_QueryEntity):
             )
         else:
             self._label_name = getattr(column, 'key', None)
+            search_entities = True
 
         self.type = type_ = column.type
         if type_.hashable:
@@ -3588,30 +3597,38 @@ class _ColumnEntity(_QueryEntity):
         # leaking out their entities into the main select construct
         self.actual_froms = actual_froms = set(column._from_objects)
 
-        all_elements = [
-            elem for elem in visitors.iterate(column, {})
-            if 'parententity' in elem._annotations
-        ]
-
-        self.entities = util.unique_list([
-            elem._annotations['parententity']
-            for elem in all_elements
-            if 'parententity' in elem._annotations
-        ])
-
-        self._from_entities = set([
-            elem._annotations['parententity']
-            for elem in all_elements
-            if 'parententity' in elem._annotations
-            and actual_froms.intersection(elem._from_objects)
-        ])
-
-        if self.entities:
-            self.entity_zero = self.entities[0]
-        elif self.namespace is not None:
-            self.entity_zero = self.namespace
+        if not search_entities:
+            self.entity_zero = _entity
+            if _entity:
+                self.entities = [_entity]
+            else:
+                self.entities = []
+            self._from_entities = set(self.entities)
         else:
-            self.entity_zero = None
+            all_elements = [
+                elem for elem in visitors.iterate(column, {})
+                if 'parententity' in elem._annotations
+            ]
+
+            self.entities = util.unique_list([
+                elem._annotations['parententity']
+                for elem in all_elements
+                if 'parententity' in elem._annotations
+            ])
+
+            self._from_entities = set([
+                elem._annotations['parententity']
+                for elem in all_elements
+                if 'parententity' in elem._annotations
+                and actual_froms.intersection(elem._from_objects)
+            ])
+
+            if self.entities:
+                self.entity_zero = self.entities[0]
+            elif self.namespace is not None:
+                self.entity_zero = self.namespace
+            else:
+                self.entity_zero = None
 
     supports_single_entity = False
 
@@ -3673,10 +3690,15 @@ class _ColumnEntity(_QueryEntity):
 
 
 class QueryContext(object):
-    multi_row_eager_loaders = False
-    adapter = None
-    froms = ()
-    for_update = None
+    __slots__ = (
+        'multi_row_eager_loaders', 'adapter', 'froms', 'for_update',
+        'query', 'session', 'autoflush', 'populate_existing',
+        'invoke_all_eagers', 'version_check', 'refresh_state',
+        'primary_columns', 'secondary_columns', 'eager_order_by',
+        'eager_joins', 'create_eager_joins', 'propagate_options',
+        'attributes', 'statement', 'from_clause', 'whereclause',
+        'order_by', 'labels', '_for_update_arg', 'runid', 'partials'
+    )
 
     def __init__(self, query):
 
@@ -3693,8 +3715,13 @@ class QueryContext(object):
             self.whereclause = query._criterion
             self.order_by = query._order_by
 
+        self.multi_row_eager_loaders = False
+        self.adapter = None
+        self.froms = ()
+        self.for_update = None
         self.query = query
         self.session = query.session
+        self.autoflush = query._autoflush
         self.populate_existing = query._populate_existing
         self.invoke_all_eagers = query._invoke_all_eagers
         self.version_check = query._version_check