Zero-Downtime PostgreSQL Migrations at Scale

--- title : " Zero-Downtime PostgreSQL Migrations at Scale" published : true description : " Advisory lock strategies, ghost table patterns, and pg_repack techniques for non-blocking schema migrations on high-traffic mobile backends." tags : postgresql, architecture, devops, api canonical_url : https://blog.mvpfactory.co/zero-downtime-postgresql-migrations-at-scale --- ## What We Will Build By the end of this tutorial, you will have a complete migration playbook for PostgreSQL that eliminates downtime during schema changes. We will walk through advisory locks for coordinating migration runners, the ghost table pattern for lock-free schema rewrites, `pg_repack` for bloat reclamation, and the `CREATE INDEX CONCURRENTLY` failure mode that silently breaks your queries. These are the patterns I use on mobile backends handling 10k+ requests per second. ## Prerequisites - PostgreSQL 14+ (the patterns work on older versions, but 14+ handles `ADD COLUMN ... DEFAULT` without table rewrites) - A