Document -extend.query-path in README. Add more examples to queries.yaml.

Author: ncabatoff

README.md

@@ -65,6 +65,10 @@ for l in StringIO(x):
 Adjust the value of the resultant prometheus value type appropriately. This helps build
 rich self-documenting metrics for the exporter.
 
+### Adding new metrics via a config file
+
+The -extend.query-path command-line argument specifies a YAML file containing additional queries to run.
+Some examples are provided in [queries.yaml](queries.yaml).
 
 ### Running as non-superuser
 

queries.yaml

@@ -1,6 +1,100 @@
 pg_replication:
-  query: 'SELECT EXTRACT(EPOCH FROM (now() - pg_last_xact_replay_timestamp()))::INT as lag'
+  query: "SELECT EXTRACT(EPOCH FROM (now() - pg_last_xact_replay_timestamp()))::INT as lag"
   metrics:
     - lag:
-        usage: 'GAUGE'
-        description: 'Replication lag behind master in seconds'
+        usage: "GAUGE"
+        description: "Replication lag behind master in seconds"
+
+pg_postmaster:
+  query: "SELECT pg_postmaster_start_time as start_time_seconds from pg_postmaster_start_time()"
+  metrics:
+    - start_time_seconds:
+        usage: "GAUGE"
+        description: "Time at which postmaster started"
+
+pg_settings_shared_buffers:
+  query: "SELECT 8192*setting as bytes from pg_settings where name = 'shared_buffers'"
+  metrics:
+    - bytes:
+        usage: "GAUGE"
+        description: "Size of shared_buffers"
+
+pg_settings_checkpoint:
+  query: "select (select setting::int from pg_settings where name = 'checkpoint_segments') as segments, (select setting::int from pg_settings where name = 'checkpoint_timeout') as timeout_seconds, (select setting::float from pg_settings where name = 'checkpoint_completion_target') as completion_target"
+  metrics:
+    - segments:
+        usage: "GAUGE"
+        description: "Number of checkpoint segments"
+    - timeout_seconds:
+        usage: "GAUGE"
+        description: "Checkpoint timeout in seconds"
+    - completion_target:
+        usage: "GAUGE"
+        description: "Checkpoint completion target, ranging from 0 to 1"
+
+pg_stat_user_tables:
+  query: "SELECT schemaname, relname, seq_scan, seq_tup_read, idx_scan, idx_tup_fetch, n_tup_ins, n_tup_upd, n_tup_del, n_tup_hot_upd, n_live_tup, n_dead_tup, n_mod_since_analyze, last_vacuum, last_autovacuum, last_analyze, last_autoanalyze, vacuum_count, autovacuum_count, analyze_count, autoanalyze_count FROM pg_stat_user_tables"
+  metrics:
+    - schemaname:
+        usage: "LABEL"
+        description: "Name of the schema that this table is in"
+    - relname:
+        usage: "LABEL"
+        description: "Name of this table"
+    - seq_scan:
+        usage: "COUNTER"
+        description: "Number of sequential scans initiated on this table"
+    - seq_tup_read:
+        usage: "COUNTER"
+        description: "Number of live rows fetched by sequential scans"
+    - idx_scan:
+        usage: "COUNTER"
+        description: "Number of index scans initiated on this table"
+    - idx_tup_fetch:
+        usage: "COUNTER"
+        description: "Number of live rows fetched by index scans"
+    - n_tup_ins:
+        usage: "COUNTER"
+        description: "Number of rows inserted"
+    - n_tup_upd:
+        usage: "COUNTER"
+        description: "Number of rows updated"
+    - n_tup_del:
+        usage: "COUNTER"
+        description: "Number of rows deleted"
+    - n_tup_hot_upd:
+        usage: "COUNTER"
+        description: "Number of rows HOT updated (i.e., with no separate index update required)"
+    - n_live_tup:
+        usage: "GAUGE"
+        description: "Estimated number of live rows"
+    - n_dead_tup:
+        usage: "GAUGE"
+        description: "Estimated number of dead rows"
+    - n_mod_since_analyze:
+        usage: "GAUGE"
+        description: "Estimated number of rows changed since last analyze"
+    - last_vacuum:
+        usage: "GAUGE"
+        description: "Last time at which this table was manually vacuumed (not counting VACUUM FULL)"
+    - last_autovacuum:
+        usage: "GAUGE"
+        description: "Last time at which this table was vacuumed by the autovacuum daemon"
+    - last_analyze:
+        usage: "GAUGE"
+        description: "Last time at which this table was manually analyzed"
+    - last_autoanalyze:
+        usage: "GAUGE"
+        description: "Last time at which this table was analyzed by the autovacuum daemon"
+    - vacuum_count:
+        usage: "COUNTER"
+        description: "Number of times this table has been manually vacuumed (not counting VACUUM FULL)"
+    - autovacuum_count:
+        usage: "COUNTER"
+        description: "Number of times this table has been vacuumed by the autovacuum daemon"
+    - analyze_count:
+        usage: "COUNTER"
+        description: "Number of times this table has been manually analyzed"
+    - autoanalyze_count:
+        usage: "COUNTER"
+        description: "Number of times this table has been analyzed by the autovacuum daemon"