Run zero-downtime schema migrations

Steps

1. 1Expand: add nullable columns/tables first; deploy code writing both paths
2. 2Backfill in batches with sleep/throttling; monitor replication lag
3. 3Switch reads to the new shape behind a flag; verify parity metrics
4. 4Contract: remove old columns only after N days of clean telemetry
5. 5Never rename or drop during peak; schedule low-traffic windows
6. 6Test every migration against a production-size snapshot first

Common Pitfalls

• ▲CREATE INDEX without CONCURRENTLY blocking writes
• ▲Deploying code that assumes new column before migration runs

Commands

$ npx skills add aniruddhaadak80/skills --skill databases-zero-downtime-migrations

$ npx skills add aniruddhaadak80/skills --skill databases-zero-downtime-migrations -g

Tags