The dag_stats endpoint returns all dags by default. This can result in an extremely large payload ~ 3mb and slow response time when you have a lot of dags (In our case 1500+).
The accompanying pull request adds a dag_ids get parameter to the dag_stats end point which is populated by the dags present on the page.
Please see previous issue for task_stats
AIRFLOW-6095 which has already been merged with a similar solution