Incident Overview
Nordwell Retail runs a three-node PostgreSQL 15 cluster (one primary, two streaming replicas) supporting its order-management service. At 02:14 local time, the on-call platform engineer, Priya, receives two alerts within four minutes of each other: replica lag has crossed 30 minutes on both replicas, and disk utilisation on the primary's data volume has crossed 78% and is still climbing.
Application dashboards show order processing latency is normal and error rates are flat, so the incident is not yet customer-visible, but the disk trend threatens to become one within a few hours if it continues unchecked.
Investigation Options
Review the available operational moves and select the best immediate action.
Query pg_replication_slots and pg_stat_replication to confirm which slot or replica is retaining WAL before changing anything.
Immediately drop the inactive logical replication slot identified on the monitoring dashboard.
Terminate the long-running autovacuum worker process on orders_history to reduce disk growth.
Temporarily raise max_wal_size and archive_timeout as an immediate mitigation while root-cause investigation continues.