Merge pull request #1592 from MITx/fix/cdodge/optimize-instructor-dashboard

additional courseware view optimizations. Do a 'depth' fetch on the sele...

common/lib/xmodule/xmodule/modulestore/mongo.py

@@ -64,7 +64,11 @@ class CachingDescriptorSystem(MakoDescriptorSystem):
         location = Location(location)
         json_data = self.module_data.get(location)
         if json_data is None:
-            return self.modulestore.get_item(location)
+            module = self.modulestore.get_item(location)
+            if module is not None:
+                # update our own cache after going to the DB to get cache miss
+                self.module_data.update(module.system.module_data)
+            return module
         else:
             # load the module and apply the inherited metadata
             try: