Added PostgresqlReplicationLagHigh rule (#456)

* Added PostgresqlReplicationLagHigh rule

* Update PostgreSQL replication lag alert settings

---------

Co-authored-by: Samuel Berthe <dev@samuel-berthe.fr>

_data/rules.yml

@@ -747,6 +747,11 @@ groups:
                 for: 6h
                 comments: |
                   See https://github.com/samber/awesome-prometheus-alerts/issues/289#issuecomment-1164842737
+              - name: Postgresql replication lag high
+                description: The PostgreSQL replication lag is high (> 60s)
+                query: "pg_replication_lag_seconds > 5"
+                severity: warning
+                for: 30s
 
       - name: SQL Server
         exporters:

dist/rules/postgresql/postgres-exporter.yml

@@ -192,3 +192,12 @@ groups:
       annotations:
         summary: Postgresql invalid index (instance {{ $labels.instance }})
         description: "The table {{ $labels.relname }} has an invalid index: {{ $labels.indexrelname }}. You should execute `DROP INDEX {{ $labels.indexrelname }};`\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
+
+    - alert: PostgresqlReplicationLagHigh
+      expr: 'pg_replication_lag_seconds > 60'
+      for: 2m
+      labels:
+        severity: warning
+      annotations:
+        summary: Postgresql replication lag high (> 60s) (instance {{ $labels.instance }})
+        description: "The PostgreSQL replication lag is high\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"