Catchup and backfill behavior in Apache Airflow - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does 'catchup' mean in Airflow?

Catchup means Airflow runs all the missed scheduled tasks from the past until the current date when the scheduler starts or DAG is enabled.

beginner

How do you disable catchup in an Airflow DAG?

Set the parameter catchup=False in the DAG definition to prevent Airflow from running past missed tasks.

beginner

What is backfill in Airflow?

Backfill is a manual command to run tasks for a specific past date range, useful for filling missing data or rerunning tasks.

intermediate

What happens if catchup is enabled and the DAG was paused for several days?

Airflow will run all the missed DAG runs for each scheduled interval from the last run date until now, catching up on all missed work.

intermediate

How does backfill differ from catchup in Airflow?

Catchup runs missed DAG runs automatically on scheduler start or DAG enable, while backfill is a manual command to run DAG runs for specific past dates.

What does setting catchup=False do in an Airflow DAG?

A Prevents running missed past DAG runs automatically

B Runs all past DAG runs immediately

C Disables the DAG permanently

D Runs the DAG only once

Setting catchup=False stops Airflow from running all missed scheduled DAG runs automatically.

Which Airflow feature lets you manually run tasks for past dates?

A Catchup

B Trigger Rule

C Scheduler

D Backfill

Backfill is the manual command to run DAG tasks for specific past date ranges.

If a DAG was paused for a week and catchup is enabled, what happens when it is unpaused?

A Only today's tasks run

B All missed DAG runs for the week run automatically

C No tasks run until next schedule

D The DAG is deleted

With catchup enabled, Airflow runs all missed DAG runs from the paused period automatically.

Which parameter controls catchup behavior in an Airflow DAG?

A catchup

B schedule_interval

C start_date

D depends_on_past

The catchup parameter enables or disables automatic running of missed DAG runs.

What is the main difference between catchup and backfill?

A Catchup is manual, backfill is automatic

B Catchup runs future tasks, backfill runs past tasks

C Catchup runs missed tasks automatically, backfill runs tasks manually for past dates

D They are the same

Catchup runs missed DAG runs automatically; backfill is a manual command to run past DAG runs.

Explain what catchup means in Airflow and how to control it.

Think about what happens when Airflow starts after missing scheduled runs.

Describe the backfill command in Airflow and when you would use it.

Consider how to run tasks for specific past dates on demand.