From 620f6a15bf490419160d544537607915749669f0 Mon Sep 17 00:00:00 2001
From: Roman Zaynetdinov <roman@neon.tech>
Date: Thu, 7 Mar 2024 19:38:55 +0200
Subject: [PATCH 1/3] Export db size, deadlocks and changed row metrics

We want to report metrics for the oldest user database.
---
 vm-image-spec.yaml | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/vm-image-spec.yaml b/vm-image-spec.yaml
index c1b7ad533a78..b0415ca4c6a0 100644
--- a/vm-image-spec.yaml
+++ b/vm-image-spec.yaml
@@ -142,6 +142,32 @@ files:
         query: |
           select datname, state, count(*) as count from pg_stat_activity where state <> '' group by datname, state;
 
+      - metric_name: pg_stats_userdb
+        type: gauge
+        help: 'Stats for the oldest non-system db'
+        key_labels:
+          - datname
+        value_label: kind
+        values:
+          - db_size
+          - deadlocks
+          # Rows
+          - inserted
+          - updated
+          - deleted
+        query: |
+          select pg_database_size(datname) as db_size, deadlocks,
+                 tup_inserted as inserted, tup_updated as updated, tup_deleted as deleted,
+                 datname
+            from pg_stat_database
+           where datname IN (
+             select datname
+               from pg_database
+              where datname <> 'postgres' and not datistemplate
+              order by oid
+              limit 1
+           );
+
 build: |
   # Build cgroup-tools
   #

From 6d615af6793e5e556c3649644a798ef2b923985f Mon Sep 17 00:00:00 2001
From: Roman Zaynetdinov <roman@neon.tech>
Date: Fri, 8 Mar 2024 14:19:26 +0200
Subject: [PATCH 2/3] Add db limit comment

---
 vm-image-spec.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/vm-image-spec.yaml b/vm-image-spec.yaml
index b0415ca4c6a0..043c50cfa6e0 100644
--- a/vm-image-spec.yaml
+++ b/vm-image-spec.yaml
@@ -155,6 +155,9 @@ files:
           - inserted
           - updated
           - deleted
+        # We export stats for only one non-system database. Without this limit
+        # it is too easy to abuse the system by creating lots of databases.
+        # We can try lifting this limit in the future after we understand the needs better.
         query: |
           select pg_database_size(datname) as db_size, deadlocks,
                  tup_inserted as inserted, tup_updated as updated, tup_deleted as deleted,

From 99891ad0a4d36a319b253dbca6ae11840b81f0ef Mon Sep 17 00:00:00 2001
From: Roman Zaynetdinov <roman@neon.tech>
Date: Fri, 8 Mar 2024 15:09:01 +0200
Subject: [PATCH 3/3] Add max_cluster_size and db_total_size

---
 vm-image-spec.yaml | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/vm-image-spec.yaml b/vm-image-spec.yaml
index 043c50cfa6e0..5b93088303f5 100644
--- a/vm-image-spec.yaml
+++ b/vm-image-spec.yaml
@@ -171,6 +171,22 @@ files:
               limit 1
            );
 
+      - metric_name: max_cluster_size
+        type: gauge
+        help: 'neon.max_cluster_size setting'
+        key_labels:
+        values: [max_cluster_size]
+        query: |
+          select setting::int as max_cluster_size from pg_settings where name = 'neon.max_cluster_size';
+
+      - metric_name: db_total_size
+        type: gauge
+        help: 'Size of all databases'
+        key_labels:
+        values: [total]
+        query: |
+          select sum(pg_database_size(datname)) as total from pg_database;
+
 build: |
   # Build cgroup-tools
   #