[+] add Total index size panel to Health Check dashboard (#1115)

* Add `indexes_size_b` column to `db_size` metric

The column returns the total index size aggregated from
`pg_stat_user_indexes`

* Add `Total index size` panel to `Health Check` dashboard

* Maintain styling for metric query

Co-authored-by: Pavlo Golub <[email protected]>

---------

Co-authored-by: Pavlo Golub <[email protected]>

Author: 0xgouda

grafana/postgres/v12/0-health-check.json

@@ -5115,24 +5115,97 @@
       "type": "stat"
     },
     {
+      "datasource": {
+        "type": "grafana-postgresql-datasource",
+        "uid": "pgwatch-metrics"
+      },
+      "description": "Total size of user indexes for the selected DB. requires db_size metric.",
       "fieldConfig": {
-        "defaults": {},
+        "defaults": {
+          "decimals": 1,
+          "mappings": [],
+          "thresholds": {},
+          "unit": "bytes"
+        },
         "overrides": []
       },
       "gridPos": {
         "h": 2,
-        "w": 12,
+        "w": 6,
         "x": 12,
         "y": 18
       },
-      "id": 48,
+      "id": 51,
+      "maxDataPoints": 100,
+      "options": {
+        "colorMode": "none",
+        "graphMode": "none",
+        "justifyMode": "auto",
+        "orientation": "horizontal",
+        "percentChangeColorMode": "standard",
+        "reduceOptions": {
+          "calcs": [],
+          "fields": "",
+          "values": false
+        },
+        "showPercentChange": false,
+        "textMode": "auto",
+        "wideLayout": true
+      },
+      "pluginVersion": "12.1.0",
+      "targets": [
+        {
+          "datasource": {
+            "type": "grafana-postgresql-datasource",
+            "uid": "pgwatch-metrics"
+          },
+          "editorMode": "code",
+          "format": "table",
+          "group": [],
+          "groupBy": [],
+          "measurement": "db_size",
+          "metricColumn": "none",
+          "orderByTime": "ASC",
+          "policy": "default",
+          "rawQuery": true,
+          "rawSql": "SELECT\n  (data->>'indexes_size_b')::int8\nFROM\n  db_size\nWHERE\n  $__timeFilter(time)\n  AND dbname = '$dbname'\nORDER BY time DESC\nLIMIT 1",
+          "refId": "A",
+          "resultFormat": "time_series",
+          "select": [],
+          "sql": {},
+          "tags": [],
+          "timeColumn": "time",
+          "where": [
+            {
+              "name": "$__timeFilter",
+              "params": [],
+              "type": "macro"
+            }
+          ]
+        }
+      ],
+      "title": "Total index size",
+      "type": "stat"
+    },
+    {
+      "fieldConfig": {
+        "defaults": {},
+        "overrides": []
+      },
+      "gridPos": {
+        "h": 7,
+        "w": 12,
+        "x": 0,
+        "y": 20
+      },
+      "id": 12,
       "options": {
         "code": {
           "language": "plaintext",
           "showLineNumbers": false,
           "showMiniMap": false
         },
-        "content": "### The preset threshold values (green / yellow / red) should be reviewed / adjusted!",
+        "content": "### Brought to you by\n\n[![Cybertec – The PostgreSQL Database Company](https://www.cybertec-postgresql.com/wp-content/uploads/2025/02/cybertec-logo-white-blue.svg)](https://www.cybertec-postgresql.com/en/)\n",
         "mode": "markdown"
       },
       "pluginVersion": "12.1.0",
@@ -5146,19 +5219,19 @@
         "overrides": []
       },
       "gridPos": {
-        "h": 7,
+        "h": 2,
         "w": 12,
-        "x": 0,
+        "x": 12,
         "y": 20
       },
-      "id": 12,
+      "id": 48,
       "options": {
         "code": {
           "language": "plaintext",
           "showLineNumbers": false,
           "showMiniMap": false
         },
-        "content": "### Brought to you by\n\n[![Cybertec – The PostgreSQL Database Company](https://www.cybertec-postgresql.com/wp-content/uploads/2025/02/cybertec-logo-white-blue.svg)](https://www.cybertec-postgresql.com/en/)\n",
+        "content": "### The preset threshold values (green / yellow / red) should be reviewed / adjusted!",
         "mode": "markdown"
       },
       "pluginVersion": "12.1.0",

internal/metrics/metrics.yaml

@@ -447,7 +447,8 @@ metrics:
         node_status: standby
     db_size:
         description: >
-            Retrieves the size of the current database and the size of the `pg_catalog` schema, providing insights into the storage usage of the database.
+            Retrieves the size of the current database, the size of the `pg_catalog` schema, and total indexes size
+            providing insights into the storage usage of the database.
             It returns the size in bytes for both the current database and the catalog schema.
             This metric helps administrators monitor database size and storage consumption.
         sqls:
@@ -458,7 +459,9 @@ metrics:
                   (select sum(pg_total_relation_size(c.oid))::int8
                    from pg_class c join pg_namespace n on n.oid = c.relnamespace
                    where nspname = 'pg_catalog' and relkind = 'r'
-                  ) as catalog_size_b
+                  ) as catalog_size_b,
+                  (select sum(pg_relation_size(indexrelid))::int8
+                from pg_stat_user_indexes) as indexes_size_b
         gauges:
             - '*'
         statement_timeout_seconds: 300