Database Migration Skill

This skill provides guidance on safe database schema evolution.

Migration Principles

• Always backward-compatible first
• Idempotent migration scripts
• Transactional DDL where supported
• Test migrations on production-scale data
• Clear rollback procedures

Strategies

• Expand-contract pattern for zero-downtime
• Shadow tables for large migrations
• Online schema change tools (gh-ost, pt-osc)
• Migration versioning and tracking

Safety

• Pre-deployment validation checks
• Automated rollback triggers
• Data integrity verification
• Point-in-time recovery readiness