Prevent high mem usage in generate_course_overview.

openedx/core/djangoapps/content/course_overviews/management/commands/generate_course_overview.py

@@ -54,4 +54,4 @@ class Command(BaseCommand):
             except InvalidKeyError:
                 raise CommandError('Invalid key specified.')
 
-        CourseOverview.get_select_courses(course_keys, force_update=options.get('force_update'))
+        CourseOverview.update_select_courses(course_keys, force_update=options.get('force_update'))

openedx/core/djangoapps/content/course_overviews/models.py

@@ -487,9 +487,10 @@ class CourseOverview(TimeStampedModel):
         return json.loads(self._pre_requisite_courses_json)
 
     @classmethod
-    def get_select_courses(cls, course_keys, force_update=False):
+    def update_select_courses(cls, course_keys, force_update=False):
         """
-        Returns CourseOverview objects for the given course_keys.
+        A side-effecting method that updates CourseOverview objects for
+        the given course_keys.
 
         Arguments:
             course_keys (list[CourseKey]): Identifies for which courses to
@@ -498,8 +499,6 @@ class CourseOverview(TimeStampedModel):
                 whether the requested CourseOverview objects should be
                 forcefully updated (i.e., re-synched with the modulestore).
         """
-        course_overviews = []
-
         log.info('Generating course overview for %d courses.', len(course_keys))
         log.debug('Generating course overview(s) for the following courses: %s', course_keys)
 
@@ -507,7 +506,7 @@ class CourseOverview(TimeStampedModel):
 
         for course_key in course_keys:
             try:
-                course_overviews.append(action(course_key))
+                action(course_key)
             except Exception as ex:  # pylint: disable=broad-except
                 log.exception(
                     'An error occurred while generating course overview for %s: %s',
@@ -517,8 +516,6 @@ class CourseOverview(TimeStampedModel):
 
         log.info('Finished generating course overviews.')
 
-        return course_overviews
-
     @classmethod
     def get_all_courses(cls, orgs=None, filter_=None):
         """

openedx/core/djangoapps/content/course_overviews/tests.py

@@ -450,13 +450,14 @@ class CourseOverviewTestCase(ModuleStoreTestCase):
             unmodified_overview = CourseOverview.get_from_id(course.id)
             self.assertEqual(unmodified_overview.version, 11)
 
-    def test_get_select_courses(self):
+    def test_update_select_courses(self):
         course_ids = [CourseFactory.create().id for __ in range(3)]
         select_course_ids = course_ids[:len(course_ids) - 1]  # all items except the last
-        self.assertEqual(
-            {course_overview.id for course_overview in CourseOverview.get_select_courses(select_course_ids)},
-            set(select_course_ids),
-        )
+        with mock.patch(
+            'openedx.core.djangoapps.content.course_overviews.models.CourseOverview.get_from_id'
+        ) as mock_get_from_id:
+            CourseOverview.update_select_courses(select_course_ids)
+            self.assertEquals(mock_get_from_id.call_count, len(select_course_ids))
 
     def test_get_all_courses(self):
         course_ids = [CourseFactory.create(emit_signals=True).id for __ in range(3)]