Question

Users report seeing stale data — they update a setting, refresh, and the old value comes back, intermittently. Your app reads from three async streaming replicas behind a load balancer and writes to the primary. `pg_stat_replication` shows replica-2 with `replay_lag` of 45 seconds while the other two are sub-second. The primary is healthy. A bulk backfill job started 20 minutes ago on the primary, and replica-2 sits in a different AZ. Disk and CPU on replica-2 look fine but `replay_lag` keeps growing. Triage and mitigate.