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Airflow & DAGs · Testing & Troubleshooting

How do you backfill six months?

Mediumairflow-35
backfillhistory

Question

How do you backfill six months of Airflow DAG runs?

Solution

Backfill = run a DAG for historical periods that weren't processed.

CLI pattern (version-dependent):

airflow dags backfill <dag_id> --start-date 2026-03-01 --end-date 2026-08-31

Modern setups may also manually trigger selected historical runs.

Precautions

Idempotency, downstream impact, DB/API load, duplicate risk, concurrency, catchup/data intervals. Six months can mean hundreds of task runs.

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