Expressed the dirty flag handling logic in terms of autocommit.

django/db/backends/__init__.py

@@ -311,7 +311,8 @@ class BaseDatabaseWrapper(object):
         to decide in a managed block of code to decide whether there are open
         changes waiting for commit.
         """
-        self._dirty = True
+        if not self.autocommit:
+            self._dirty = True
 
     def set_clean(self):
         """

django/db/backends/postgresql_psycopg2/base.py

@@ -202,10 +202,6 @@ class DatabaseWrapper(BaseDatabaseWrapper):
                 level = self.isolation_level
             self.connection.set_isolation_level(level)
 
-    def set_dirty(self):
-        if self.transaction_state and self.transaction_state[-1]:
-            super(DatabaseWrapper, self).set_dirty()
-
     def check_constraints(self, table_names=None):
         """
         To check constraints, we set constraints to immediate. Then, when, we're done we must ensure they