Project Every Record Counts: Data Engineering for Backend Engineers
Part 21: "Every Record Counts" — Completeness and Correctness Engineering
Farah wants the 0.7% explained to the record. Rohan proves it: the board-deck waterfall closes to the penny, every pound the payment provider settled for the UK is traced to gold revenue or to a legitimate reason, and re-sent till baskets are decided once at the door and kept out of gold. Completeness and uniqueness as engineered properties: natural dedup keys, effectively-once delivery, control and hash totals at every hop, a daily control table gating publish in Airflow, late-data policy, restatement and a replay runbook.