Fixed #18702 -- Removed chunked reads from QuerySet iteration

docs/releases/1.6.txt

@@ -524,6 +524,25 @@ non-standard behavior has been preserved but moved to the model form field layer
 and occurs only when the associated widget is
 :class:`~django.forms.SelectMultiple` or a subclass.
 
+QuerySet iteration
+~~~~~~~~~~~~~~~~~~
+
+The ``QuerySet`` iteration was changed to immediately convert all fetched
+rows to ``Model`` objects. In Django 1.5 and earlier the fetched rows were
+converted to ``Model`` objects in chunks of 100.
+
+Existing code will work, but the amount of rows converted to objects
+might change in certain use cases. Such usages include partially looping
+over a queryset or any usage which ends up doing ``__bool__`` or
+``__contains__``.
+
+Notably most database backends did fetch all the rows in one go already in
+1.5.
+
+It is still possible to convert the fetched rows to ``Model`` objects
+lazily by using the :meth:`~django.db.models.query.QuerySet.iterator()`
+method.
+
 Miscellaneous
 ~~~~~~~~~~~~~