Fix activity query

* Modify the activity query to ensure each state is always reported.

* Fix the activity preprocessor to unwrap the value from the array
  containing it.

sample-config/pgmon-metrics.yml

@@ -196,12 +196,28 @@ metrics:
     type: set
     query:
       0: >
-        SELECT state,
+        SELECT
-               count(*) AS backend_count,
+          states.state,
-               COALESCE(EXTRACT(EPOCH FROM max(now() - state_change)), 0) AS max_state_time
+          COALESCE(a.backend_count, 0) AS backend_count,
-        FROM pg_stat_activity
+          COALESCE(a.max_state_time, 0) AS max_state_time
-        WHERE datname = %(dbname)s
+        FROM (
-        GROUP BY state
+          SELECT state,
+                 count(*) AS backend_count,
+                 COALESCE(EXTRACT(EPOCH FROM now() - min(state_change)), 0) AS max_state_time
+          FROM pg_stat_activity
+          WHERE datname = %(dbname)s
+          GROUP BY state
+        ) AS a
+        RIGHT JOIN
+          unnest(ARRAY[
+            'active',
+            'idle',
+            'idle in transaction',
+            'idle in transaction (aborted)',
+            'fastpath function call',
+            'disabled'
+          ]) AS states(state)
+        USING (state);
     test_args:
       dbname: postgres
 
@@ -235,7 +251,7 @@ metrics:
   locks:
     type: row
     query:
-      0:
+      0: >
         SELECT COUNT(*) AS total,
                SUM(CASE WHEN granted THEN 1 ELSE 0 END) AS granted
         FROM pg_locks

zabbix_templates/pgmon_templates.yaml

@@ -411,7 +411,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "active")].max_state_time'
+                    - '$[?(@.state == "active")].max_state_time.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -429,7 +429,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "active")].backend_count'
+                    - '$[?(@.state == "active")].backend_count.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -448,7 +448,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "disabled")].max_state_time'
+                    - '$[?(@.state == "disabled")].max_state_time.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -466,7 +466,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "disabled")].backend_count'
+                    - '$[?(@.state == "disabled")].backend_count.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -485,7 +485,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "fastpath function call")].max_state_time'
+                    - '$[?(@.state == "fastpath function call")].max_state_time.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -503,7 +503,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "fastpath function call")].backend_count'
+                    - '$[?(@.state == "fastpath function call")].backend_count.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -522,7 +522,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "idle")].max_state_time'
+                    - '$[?(@.state == "idle")].max_state_time.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -540,7 +540,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "idle")].backend_count'
+                    - '$[?(@.state == "idle")].backend_count.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -559,7 +559,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "idle in transaction (aborted)")].max_state_time'
+                    - '$[?(@.state == "idle in transaction (aborted)")].max_state_time.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -577,7 +577,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "idle in transaction (aborted)")].backend_count'
+                    - '$[?(@.state == "idle in transaction (aborted)")].backend_count.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -596,7 +596,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "idle in transaction")].max_state_time'
+                    - '$[?(@.state == "idle in transaction")].max_state_time.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -614,7 +614,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "idle in transaction")].backend_count'
+                    - '$[?(@.state == "idle in transaction")].backend_count.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -633,7 +633,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "starting")].max_state_time'
+                    - '$[?(@.state == "starting")].max_state_time.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags:
@@ -651,7 +651,7 @@ zabbix_export:
               preprocessing:
                 - type: JSONPATH
                   parameters:
-                    - '$[?(@.state == "starting")].backend_count'
+                    - '$[?(@.state == "starting")].backend_count.first()'
               master_item:
                 key: 'pgmon_connection_states[{#DBNAME}]'
               tags: