Stopped flipping the uses_savepoints feature at runtime.

django/db/backends/__init__.py

@@ -161,17 +161,17 @@ class BaseDatabaseWrapper(object):
     ##### Backend-specific savepoint management methods #####
 
     def _savepoint(self, sid):
-        if not self.features.uses_savepoints:
+        if not self.features.uses_savepoints or self.autocommit:
             return
         self.cursor().execute(self.ops.savepoint_create_sql(sid))
 
     def _savepoint_rollback(self, sid):
-        if not self.features.uses_savepoints:
+        if not self.features.uses_savepoints or self.autocommit:
             return
         self.cursor().execute(self.ops.savepoint_rollback_sql(sid))
 
     def _savepoint_commit(self, sid):
-        if not self.features.uses_savepoints:
+        if not self.features.uses_savepoints or self.autocommit:
             return
         self.cursor().execute(self.ops.savepoint_commit_sql(sid))
 

django/db/backends/postgresql_psycopg2/base.py

@@ -49,6 +49,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     has_select_for_update = True
     has_select_for_update_nowait = True
     has_bulk_insert = True
+    uses_savepoints = True
     supports_tablespaces = True
     supports_transactions = True
     can_distinct_on_fields = True
@@ -88,8 +89,6 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         self.introspection = DatabaseIntrospection(self)
         self.validation = BaseDatabaseValidation(self)
 
-        self.features.uses_savepoints = False
-
     def get_connection_params(self):
         settings_dict = self.settings_dict
         if not settings_dict['NAME']:
@@ -174,7 +173,6 @@ class DatabaseWrapper(BaseDatabaseWrapper):
             self.cursor().close()
         if managed and self.autocommit:
             self.set_autocommit(False)
-            self.features.uses_savepoints = True
 
     def _leave_transaction_management(self, managed):
         """
@@ -186,7 +184,6 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         if not managed and not self.autocommit:
             self.rollback()                     # Must terminate transaction first.
             self.set_autocommit(True)
-            self.features.uses_savepoints = False
 
     def _set_isolation_level(self, isolation_level):
         assert isolation_level in range(1, 5)     # Use set_autocommit for level = 0