Database DevOps schema migration strategies

Implement database DevOps with automated schema migrations, backup strategies, and zero-downtime deployments. Migration frameworks: 1. Flyway: version-based migrations, checksum validation, rollback support, team collaboration. 2. Liquibase: XML/YAML changesets, database-agnostic, conditional execution. 3. Alembic (Python): revision control, branching support, auto-generation from models. Database CI/CD: 1. Schema testing: unit tests for stored procedures, data validation, performance regression testing. 2. Environment promotion: dev → test → staging → production with data anonymization. 3. Deployment automation: blue-green database deployments, read replica promotion. Zero-downtime strategies: 1. Backward-compatible changes: additive migrations, column defaults, index creation online. 2. Multi-phase deployment: expand (add new), migrate (data transformation), contract (remove old). 3. Shadow tables: parallel table structures, gradual data migration, validation queries. Backup and recovery: 1. Automated backups: daily full backups, transaction log backups every 15 minutes. 2. Cross-region replication: RTO < 4 hours, RPO < 1 hour for critical systems. 3. Disaster recovery testing: monthly failover tests, recovery time validation. Performance monitoring: 1. Query performance: slow query logging (>1 second), index optimization recommendations. 2. Connection pooling: PgBouncer, connection limits based on server capacity. Database security: encryption at rest, TDE implementation, access control with least privilege, audit logging for sensitive operations.