Zero-Downtime Migration (2026)

Database migration patterns that ensure continuous service availability during schema changes.

Overview

• Deploying schema changes to production systems with uptime requirements
• Renaming or removing columns without breaking existing application code
• Adding NOT NULL constraints to existing columns with data
• Creating indexes on large tables without locking
• Migrating data between columns or tables during live traffic
• Using pgroll for automated expand-contract migrations

Quick Reference

Expand-Contract Overview