database-migrations

Zero-downtime database migrations in PostgreSQL use the expand-contract pattern to separate schema and data changes, preventing table locks. This approach ensures applications remain operational by deploying backward-compatible schema updates incrementally before removing deprecated structures.

Adding a non-nullable column to a large table requires a multi-step migration strategy to avoid locking. You must first deploy the column as nullable, backfill existing rows, and enforce constraints at the application layer before finally applying the non-null database constraint.

Yes, this guide provides specific schema migration workflows and patterns for Drizzle and Prisma. It covers safe deployment strategies tailored to these ORMs, ensuring reversible schema changes and preventing inline indexing anti-patterns on large production tables.

Rolling back a failed production migration requires immutability and prior rollback planning during the initial schema change design. The guide details creating reversible migration steps for tools like Django and golang-migrate to safely restore previous database states without data loss.

Inline indexing on large tables during schema migrations causes severe table locking and application downtime. The guide identifies this as a critical anti-pattern, recommending explicit, concurrent index creation strategies instead to maintain database availability.