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Data Engineer Pe Airflow Scheduling Dependencies Interview Questions

75 verified Data Engineer Pe Airflow Scheduling Dependencies interview questions — solve with answers, learn from explanations, test yourself in a real simulation.

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Sample questions

Pe Airflow Scheduling DependenciesDifficulty 2
In Airflow 2.x, for a DAG with a daily schedule, what does a DagRun's logical_date represent?
  • aThe start of the data interval a DagRun covers, not when it runs✓
  • bThe wall-clock time the scheduler actually started running the DagRun
  • cThe timestamp when the DAG's last task instance finished
  • dA random identifier Airflow assigns to the DagRun
Explanation:In Airflow 2.x, logical_date marks the start of the data interval a DagRun covers, not the actual execution time — a daily DAG typically runs after the interval closes, not at its start.
Pe Airflow Scheduling DependenciesDifficulty 1
In Airflow 2.x, which context variable replaced the deprecated execution_date?
  • arun_id
  • bdata_timestamp
  • cscheduled_at
  • dlogical_date✓
Explanation:execution_date was deprecated starting Airflow 2.2 in favor of logical_date, which better reflects that the value marks interval start rather than run time.
Pe Airflow Scheduling DependenciesDifficulty 2
In Airflow 2.x, for a DAG with schedule='@daily', when does Airflow typically trigger the DagRun for a given day's data interval?
  • aAt the start of that day, 00:00
  • bAfter that day's interval has closed, i.e. next day's 00:00✓
  • cExactly 12 hours into the day
  • dOnly when a user manually clicks 'Trigger DAG'
Explanation:In Airflow 2.x's default CronDataIntervalTimetable, a DagRun is scheduled after its data interval ends so Airflow can be sure all of that interval's data is available to process.
Pe Airflow Scheduling DependenciesDifficulty 2
A DAG is defined as follows:
dag = DAG(
    "daily_etl",
    start_date=datetime(2024, 1, 1),
    schedule="@daily",
    catchup=True,
)

Today is 2024-01-10 and the DAG has never run before. What happens when it is unpaused?
  • aAirflow only creates a single DagRun for the current day and ignores the past
  • bIt creates a DagRun for each missed daily interval since start_date✓
  • cAirflow refuses to run until the user manually changes start_date to today
  • dAirflow deletes the DAG because too many intervals were missed
Explanation:catchup=True makes the scheduler backfill every missed scheduled interval since start_date, creating a DagRun for each one.
Pe Airflow Scheduling DependenciesDifficulty 1
What does catchup=False change compared to the default catchup behavior?
  • aAirflow runs all missed intervals but in reverse chronological order
  • bAirflow disables retries for every task in the DAG
  • cIt skips the missed intervals and schedules only from the most recent one✓
  • dAirflow prevents the DAG from ever being manually triggered
Explanation:catchup=False tells the scheduler to ignore intervals missed while the DAG was inactive and start scheduling from the most recent interval onward.
Pe Airflow Scheduling DependenciesDifficulty 2
What is the purpose of the airflow dags backfill CLI command?
  • aIt creates DagRuns for a chosen date range, independent of catchup✓
  • bIt permanently changes the DAG's catchup setting in the database
  • cIt only re-runs tasks that are currently in a failed state
  • dIt deletes all existing DagRuns for the DAG before recreating the schedule
Explanation:airflow dags backfill lets an operator explicitly request runs for a specific interval range on demand, regardless of whether catchup is enabled.

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