vm-image: Expose new LFC working set size metrics

vm-image-spec.yaml

@@ -236,6 +236,7 @@ files:
         query: |
           select sum(pg_database_size(datname)) as total from pg_database;
 
+      # DEPRECATED
       - metric_name: lfc_approximate_working_set_size
         type: gauge
         help: 'Approximate working set size in pages of 8192 bytes'
@@ -244,6 +245,20 @@ files:
         query: |
           select neon.approximate_working_set_size(false) as approximate_working_set_size;
 
+      - metric_name: lfc_approximate_working_set_size_windows
+        type: gauge
+        help: 'Approximate working set size in pages of 8192 bytes'
+        key_labels: [duration]
+        values: [size]
+        # NOTE: This is the "public" / "human-readable" version. Here, we supply a small selection
+        # of durations in a pretty-printed form.
+        query: |
+          select
+            x as duration,
+            neon.approximate_working_set_size_seconds(extract('epoch' from x::interval)::int) as size
+          from
+            (values ('5m'),('15m'),('1h')) as t (x);
+
       - metric_name: current_lsn
         type: gauge
         help: 'Current LSN of the database'
@@ -377,13 +392,19 @@ files:
         query: |
           select pg_size_bytes(current_setting('neon.file_cache_size_limit')) as lfc_cache_size_limit;
 
-      - metric_name: lfc_approximate_working_set_size
+      - metric_name: lfc_approximate_working_set_size_windows
         type: gauge
         help: 'Approximate working set size in pages of 8192 bytes'
-        key_labels:
-        values: [approximate_working_set_size]
+        key_labels: [duration_seconds]
+        values: [size]
+        # NOTE: This is the "internal" / "machine-readable" version. This outputs the working set
+        # size looking back 1..60 minutes, labeled with the number of minutes.
         query: |
-          select neon.approximate_working_set_size(false) as approximate_working_set_size;
+          select
+            x::text as duration_seconds,
+            neon.approximate_working_set_size_seconds(x) as size
+          from
+            (select generate_series * 60 as x from generate_series(1, 60));
 build: |
   # Build cgroup-tools
   #