Fix ID age query and template

sample-config/pgmon-metrics.yml

@@ -22,7 +22,7 @@ metrics:
   max_frozen_age:
     type: row
     query:
-      0: SELECT max(age(datfrozenxid)), max(mxid_age(datminmxid)) FROM pg_database
+      0: SELECT max(age(datfrozenxid)) AS xid_age, max(mxid_age(datminmxid)) AS mxid_age FROM pg_database
 
   # Per-database metrics
   db_stats:
@@ -47,12 +47,6 @@ metrics:
     test_args:
       repid: 127.0.0.1_test_rep
 
-  # Debugging
-  sleep:
-    type: value
-    query:
-      0: SELECT now(), pg_sleep(5);
-
   # Per-slot metrics
   slot_stats:
     type: row