RDS PostgreSQL 13 to 15 Upgrade with GCP DataStream
We upgraded our AWS RDS PostgreSQL instance from version 13 to 15. On paper it looks like a few clicks in the console. In practice, with logical replication and a CDC pipeline involved, there are several things that will block or break the upgrade if you do not handle them in the right order. Context RDS instance: db.m5.4xlarge, ~1.5TB database, primary + read-replica ~5000 API requests/min at peak load GCP DataStream connected to BigQuery via logical replication – this is the main complication Custom parameter group on both primary and read-replica with logical replication enabled No blue-green deployment on AWS RDS, so this is an in-place upgrade with real downtime BigQuery will show roughly 1 hour of data loss for the period the slot was dropped – DataStream cannot backfill that gap automatically. AWS does offer a manual backfill option but it has additional cost associated with it Because there is no blue-green option here, the ~8 minutes of downtime is real and users will see it. Planning matters. ...