diff --git a/lib/cartodb/controllers/layergroup.js b/lib/cartodb/controllers/layergroup.js
index 0f5512d6..899e35eb 100644
--- a/lib/cartodb/controllers/layergroup.js
+++ b/lib/cartodb/controllers/layergroup.js
@@ -600,6 +600,7 @@ LayergroupController.prototype.getAffectedTables = function (user, dbName, layer
                     return callback(err);
                 }
 
+                // feed affected tables cache so it can be reused from, for instance, map controller
                 this.layergroupAffectedTables.set(dbName, layergroupId, tables);
 
                 callback(null, tables);