[Composer][airflow_db_cleanup] - All DAGs runs older than `max_db_entry_age_in_days` are deleted

从 composer/workflows/airflow_db_cleanup.py 开始，检查 list_dags 和 dag_id 是如何传递给 build_query 的。将显示的更改与链接的 commit 进行比较，并验证清理过程绝不会生成未限定范围的查询；完成的标准是移除较早的运行记录，同时不删除每个 DAG 保留的最新运行记录。

In which file did you encounter the issue?

composer/workflows/airflow_db_cleanup.py

Did you change the file? If so, how?

            dags = session.query(airflow_db_model.dag_id).distinct()
            session.commit()

-            list_dags = [str(list(dag)[0]) for dag in dags] + [None]
+            list_dags = [str(list(dag)[0]) for dag in dags]
            for dag_id in list_dags:
                query = build_query(
                    session=session,

Describe the issue

Since this commit which removed a check on whether dag_id argument is None, running the airflow_db_cleanup DAG will result in deleting all DAGs runs older than max_db_entry_age_in_days across all DAG IDs without keeping the at least the latest run for each DAG.

As shown in the logs for the final iteration [None] this generates the following query:

[2025-09-19T13:24:14.981+0000] {airflow_db_cleanup.py:378} INFO - Query: SELECT dag_run.state AS dag_run_state, dag_run.id AS dag_run_id, dag_run.dag_id AS dag_run_dag_id, dag_run.queued_at AS dag_run_queued_at,
dag_run.execution_date AS dag_run_execution_date, dag_run.start_date AS dag_run_start_date, dag_run.end_date AS dag_run_end_date, dag_run.run_id AS dag_run_run_id, dag_run.creating_job_id AS dag_run_creating_job_id,
dag_run.external_trigger AS dag_run_external_trigger, dag_run.run_type AS dag_run_run_type, dag_run.conf AS dag_run_conf, dag_run.data_interval_start AS dag_run_data_interval_start,
dag_run.data_interval_end AS dag_run_data_interval_end, dag_run.last_scheduling_decision AS dag_run_last_scheduling_decision, dag_run.dag_hash AS dag_run_dag_hash,
dag_run.log_template_id AS dag_run_log_template_id, dag_run.updated_at AS dag_run_updated_at, dag_run.clear_number AS dag_run_clear_number
FROM dag_run
WHERE dag_run.execution_date <= %(execution_date_1)s