diff --git a/django/db/backends/util.py b/django/db/backends/util.py
index b0463b79af..3ba1cb00cd 100644
--- a/django/db/backends/util.py
+++ b/django/db/backends/util.py
@@ -16,9 +16,12 @@ class CursorWrapper(object):
         self.cursor = cursor
         self.db = db
 
-    def __getattr__(self, attr):
+    def set_dirty(self):
         if self.db.is_managed():
             self.db.set_dirty()
+
+    def __getattr__(self, attr):
+        self.set_dirty()
         if attr in self.__dict__:
             return self.__dict__[attr]
         else:
@@ -31,6 +34,7 @@ class CursorWrapper(object):
 class CursorDebugWrapper(CursorWrapper):
 
     def execute(self, sql, params=()):
+        self.set_dirty()
         start = time()
         try:
             return self.cursor.execute(sql, params)
@@ -47,6 +51,7 @@ class CursorDebugWrapper(CursorWrapper):
             )
 
     def executemany(self, sql, param_list):
+        self.set_dirty()
         start = time()
         try:
             return self.cursor.executemany(sql, param_list)
diff --git a/tests/regressiontests/transactions_regress/tests.py b/tests/regressiontests/transactions_regress/tests.py
index 22f1b0f911..59722630df 100644
--- a/tests/regressiontests/transactions_regress/tests.py
+++ b/tests/regressiontests/transactions_regress/tests.py
@@ -4,6 +4,7 @@ from django.core.exceptions import ImproperlyConfigured
 from django.db import connection, transaction
 from django.db.transaction import commit_on_success, commit_manually, TransactionManagementError
 from django.test import TransactionTestCase, skipUnlessDBFeature
+from django.test.utils import override_settings
 from django.utils.unittest import skipIf
 
 from .models import Mod, M2mA, M2mB
@@ -166,6 +167,13 @@ class TestTransactionClosing(TransactionTestCase):
         except:
             self.fail("A transaction consisting of a failed operation was not closed.")
 
+    @override_settings(DEBUG=True)
+    def test_failing_query_transaction_closed_debug(self):
+        """
+        Regression for #6669. Same test as above, with DEBUG=True.
+        """
+        self.test_failing_query_transaction_closed()
+
 
 class TestManyToManyAddTransaction(TransactionTestCase):
     def test_manyrelated_add_commit(self):