migration-safety

Prevent production incidents during database schema migrations by enforcing safe migration patterns, detecting dangerous operations like unbatched updates, and mandating rollback path documentation before deployment. This validation approach avoids irreversible data loss and application downtime.

The expand-contract pattern for zero-downtime migrations deploys destructive schema changes in phases: expanding the schema first, deploying application changes, then contracting by removing old columns. This avoids locking tables and prevents application downtime during column type changes or removals.

Safely add a NOT NULL column to a large production table by following safe backfill steps rather than locking the table for hours. The migration-safety process flags dangerous patterns and validates pre-migration safety checks to ensure data integrity on large datasets.

Migration safety validation works with all relational and NoSQL database systems and ORM migration frameworks. It applies to migration authoring, pull request review, and pre-release validation tasks to enforce safe patterns across diverse database environments.

Dangerous database migration patterns to avoid include adding NOT NULL constraints without prior backfills, dropping columns or tables, unbatched large table updates, and adding unique constraints without duplicate checks. Detecting these high-risk patterns prevents unrecoverable schema or data changes.

Create a rollback plan for a database migration by using pre-release validation checklists to confirm rollback paths exist and document irreversible changes before production deployment. This ensures mandatory rollback procedures are prepared to prevent unrecoverable data loss.