System Design6 July 20268 min read

Zero-Downtime Database Migrations: The Expand-Contract Pattern in Production

How to rename database columns and alter schema types on 500-million row Postgres tables without holding table locks.

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Zero-Downtime Database Migrations: The Expand-Contract Pattern in Production Cover

Postgres Schema Architecture

Phase 1: Expand, Phase 2: Dual Write & Backfill, Phase 3: Contract.

#System Design #SQL

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