From 99c19cad24b5bb5974403a1e2541fe28ac4c0d53 Mon Sep 17 00:00:00 2001
From: Tristan Partin <tristan@neon.tech>
Date: Fri, 16 Aug 2024 12:44:12 -0500
Subject: [PATCH] Add compute_receive_lsn metric

Useful for dashboarding the replication metrics of a single endpoint.

Signed-off-by: Tristan Partin <tristan@neon.tech>
---
 vm-image-spec.yaml | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/vm-image-spec.yaml b/vm-image-spec.yaml
index 8c1c4512b4..d1cfbda15d 100644
--- a/vm-image-spec.yaml
+++ b/vm-image-spec.yaml
@@ -272,6 +272,19 @@ files:
               else (pg_current_wal_lsn() - '0/0')::FLOAT8
             end as lsn;
 
+      - metric_name: compute_receive_lsn
+        type: gauge
+        help: 'Returns the last write-ahead log location that has been received and synced to disk by streaming replication'
+        key_labels:
+        values: [lsn]
+        query: |
+          SELECT
+            CASE
+              WHEN pg_catalog.pg_is_in_recovery()
+              THEN (pg_last_wal_receive_lsn() - '0/0')::FLOAT8
+              ELSE 0
+            END AS lsn;
+
       - metric_name: replication_delay_bytes
         type: gauge
         help: 'Bytes between received and replayed LSN'