migration-planner

To check database migration risks, you need a pre-flight analysis that identifies data-loss exposure, lock impact, and rollback paths before executing schema changes. This assessment evaluates downtime risks and affected code blast radius for proposed migrations.

A zero-downtime database migration uses expand and contract rollout patterns to apply schema changes without locking tables or interrupting service. You need it when modifying large tables where standard migrations would cause unacceptable production outages.

Planning a rollback for a failed database schema migration requires mapping honest reversal paths before execution, accounting for irreversible data loss. A pre-migration risk dossier outlines these rollback steps to ensure safe recovery from failed schema changes.

Yes, the migration risk analysis supports common migration systems and ORMs including Prisma, Alembic, Django, ActiveRecord, Flyway, and Knex. It auto-detects project context to ground the assessment in the specific database engine and existing migration conventions.

To add a NOT NULL column to a large table without locking the database, use a batched backfill strategy combined with a zero-downtime expand and contract rollout. Pre-migration analysis identifies full-table rewrite lock risks and provides safe backfill steps to prevent downtime.

The limitation of analyzing schema migrations before execution is that it provides a read-only, human-gated risk assessment rather than automatically applying fixes. It identifies downtime risks and code blast radius but requires manual implementation of the suggested rollout paths.