How To Run Logical Replication On A Production PostgreSQL Cluster

Upgrading PostgreSQL in production is not fun. You have real data, real users, and a version of Postgres that’s probably several major releases behind. The obvious approach (dump, upgrade, restore) works fine on a 10GB database on a Saturday night. It doesn’t work when you have TBs of data, applications that can’t afford hours of downtime, and a team watching the monitoring dashboard at 2am.