The Replication Lag alert notifies you when its configured condition is met on PostgreSQL instances so you can investigate and respond.
Mini DBA describes this alert as: Lag In Seconds Seconds it takes to replicate from this instance to a secondary and be notified secondary has applied transaction. This may indicate periods of very high activity on secondary or bad network conditions. Mini DBA evaluates this alert once a minute so changes are detected quickly.
This alert protects high availability and disaster recovery by warning when replicas, replication slots, or apply processes fall behind. Lag can turn a planned failover into data loss risk or leave reporting users looking at stale data.
Enable it where replication, read replicas, failover, or reporting copies are part of the service design. Disable it on standalone systems that do not use replication so the alert list stays focused.
Threshold meaning: Seconds. Major threshold: 60 seconds. Minor threshold: 30 seconds. Comparison direction: over. For an over-threshold alert, decreasing a threshold makes that severity fire sooner; increasing it tolerates more load or pressure. Set the minor threshold as an early-warning level and the major threshold at the highest acceptable value for the service.
Check the sender, receiver, apply process, network path, and oldest retained log position. Restart failed replication workers only after capturing the error, then address the root cause such as disk pressure, long transactions, schema drift, network latency, or insufficient replica capacity.
For recovery and replication alerts, route notifications to the people who own recovery objectives. Higher thresholds can be reasonable for reporting replicas, but production failover paths normally need tighter settings and explicit escalation.