edits

Author: timgraham

django_mongodb_backend/query.py

@@ -187,7 +187,7 @@ def _get_reroot_replacements(expression):
         extra_conditions.append(
             extra.replace_expressions(replacements).as_mql(compiler, connection)
         )
-    # pushed_filter_expression is a filter expression from the outer WHERE
+    # pushed_filter_expression is a Where expression from the outer WHERE
     # clause that involves fields from the joined (right-hand) table and
     # possibly the outer (left-hand) table. If it can be safely evaluated
     # within the $lookup pipeline (e.g., field comparisons like

docs/source/releases/5.2.x.rst

@@ -32,7 +32,13 @@ Bug fixes
   databases.
 - :meth:`QuerySet.explain() <django.db.models.query.QuerySet.explain>` now
   :ref:`returns a string that can be parsed as JSON <queryset-explain>`.
+
+Performance improvements
+------------------------
+
 - Improved ``QuerySet`` performance by removing low limit on server-side chunking.
+- Improved ``QuerySet`` join (``$lookup``) performance by pushing some simple
+  conditions from the ``WHERE`` (``$match``) clause to the ``$lookup`` stage.
 
 5.2.0 beta 1
 ============