database-migration
Installation
SKILL.md
Database Migration
Purpose
Plan and execute database migrations including schema changes, cross-engine migration, zero-downtime deployments, and rollback strategies.
Architecture Decision Trees
Online vs Offline Migration
| Factor | Offline | Online (CDC) |
|---|---|---|
| Downtime | Hours (full lock) | Minutes or zero |
| Complexity | Low | High |
| Data volume | Any | Any |
| Consistency | Guaranteed (locked) | Eventual (CDC catch-up) |
| Rollback | Snapshot restore | Reverse CDC |
| Tooling | pg_dump/mysqldump | DMS, Debezium, GoldenGate |
| Best for | <50GB, maintenance window | Large DBs, 24/7 apps |