# Backfill

> Source: https://sukruyusufkaya.com/en/glossary/backfill
> Updated: 2026-05-13T20:01:48.774Z
> Type: glossary
> Category: veri-muhendisligi-ve-ai-altyapisi
**TLDR:** The process of reprocessing historical periods or filling missing historical data gaps after the fact.

<p>Backfill is a critical operation in data engineering used to regenerate historical data or fill missing historical periods. It often becomes necessary when new business rules are introduced, model logic changes, or a pipeline defect is corrected. If not handled carefully, backfills can create duplicate data, excessive cost, and timeline disruption. Strong backfill design must be considered together with idempotency and lineage.</p>