Add archive ready and temp file items to template

- Add the initital item definitions to the template for archive ready
  files and temp files.

- Fix the temp file query to be able to return both columns in all
  cases.

sample-config/pgmon-metrics.yml

@@ -120,25 +120,27 @@ metrics:
     type: row
     query:
       120000: >
-        SELECT count(*) AS count, coalesce(sum(size), 0) AS size
+        SELECT count(*) AS count,
+               coalesce(sum(size), 0) AS size
         FROM pg_ls_tmpdir()
         WHERE name LIKE 'pgsql_tmp%%'
       90500: >
-        SELECT count(*) AS count, coalesce(sum((pg_stat_file(name)).size), 0) AS size
+        SELECT count(*) AS count,
+               coalesce(sum((pg_stat_file(name)).size), 0) AS size
         FROM pg_ls_dir('base/pgsql_tmp/', true, false) AS name
         WHERE name LIKE 'pgsql_tmp%%'
       0: >
-        SELECT
-          CASE WHEN (
-            SELECT count(*)
-            FROM pg_ls_dir('base') AS 
-            base WHERE base = 'pgsql_tmp') = 0
-          THEN 0
-          ELSE (
-            SELECT count(*)
+          SELECT count(*) AS count,
+                 coalesce(sum((pg_stat_file(files.name)).size), 0) AS size
+          FROM (
+            SELECT name
+            FROM pg_ls_dir('base') AS name
+            WHERE name = 'pgsql_tmp') AS dir
+          LEFT JOIN (
+            SELECT name
             FROM pg_ls_dir('base/pgsql_tmp/') AS name
-            WHERE name LIKE 'pgsql_tmp%%')
-          END
+            WHERE name LIKE 'pgsql_tmp%%') AS files
+          ON dir.name IS NOT NULL
 
 
   ready_archive_files:
@@ -162,7 +164,9 @@ metrics:
             SELECT count(*)
             FROM pg_ls_dir('pg_xlog/') AS f
             WHERE f = 'archive_status') = 0
-          THEN 0
+          THEN (
+            SELECT 0 AS count
+          )
           ELSE (
             SELECT count(*) AS count
             FROM pg_ls_dir('pg_xlog/archive_status/') AS name