Compute graders just once per Course.

cms/djangoapps/contentstore/views/item.py

@@ -589,7 +589,7 @@ def _get_module_info(xblock, rewrite_static_links=True):
 
 
 def create_xblock_info(xblock, data=None, metadata=None, include_ancestor_info=False, include_child_info=False,
-                       course_outline=False, include_children_predicate=NEVER, parent_xblock=None):
+                       course_outline=False, include_children_predicate=NEVER, parent_xblock=None, graders=None):
     """
     Creates the information needed for client-side XBlockInfo.
 
@@ -626,13 +626,17 @@ def create_xblock_info(xblock, data=None, metadata=None, include_ancestor_info=F
     is_xblock_unit = is_unit(xblock, parent_xblock)
     is_unit_with_changes = is_xblock_unit and modulestore().has_changes(xblock.location)
 
+    if graders is None:
+        graders = CourseGradingModel.fetch(xblock.location.course_key).graders
+
     # Compute the child info first so it can be included in aggregate information for the parent
     should_visit_children = include_child_info and (course_outline and not is_xblock_unit or not course_outline)
     if should_visit_children and xblock.has_children:
         child_info = _create_xblock_child_info(
             xblock,
             course_outline,
-            include_children_predicate=include_children_predicate
+            graders,
+            include_children_predicate=include_children_predicate,
         )
     else:
         child_info = None
@@ -641,7 +645,6 @@ def create_xblock_info(xblock, data=None, metadata=None, include_ancestor_info=F
     release_date = get_default_time_display(xblock.start) if xblock.start != DEFAULT_START_DATE else None
     published = modulestore().has_item(xblock.location, revision=ModuleStoreEnum.RevisionOption.published_only)
 
-    graders = CourseGradingModel.fetch(xblock.location.course_key).graders
     xblock_info = {
         "id": unicode(xblock.location),
         "display_name": xblock.display_name_with_default,
@@ -777,7 +780,7 @@ def _create_xblock_ancestor_info(xblock, course_outline):
     }
 
 
-def _create_xblock_child_info(xblock, course_outline, include_children_predicate=NEVER):
+def _create_xblock_child_info(xblock, course_outline, graders, include_children_predicate=NEVER):
     """
     Returns information about the children of an xblock, as well as about the primary category
     of xblock expected as children.
@@ -794,7 +797,8 @@ def _create_xblock_child_info(xblock, course_outline, include_children_predicate
             create_xblock_info(
                 child, include_child_info=True, course_outline=course_outline,
                 include_children_predicate=include_children_predicate,
-                parent_xblock=xblock
+                parent_xblock=xblock,
+                graders=graders
             ) for child in xblock.get_children()
         ]
     return child_info