Comment out inefficient pg_stat_statements metric (#3039)

* Comment out inefficient pg_stat_statements metric

* Minor tweaks

chart/compass/charts/prometheus-postgres-exporter/values.yaml

@@ -223,76 +223,57 @@ config:
             usage: "GAUGE"
             description: "Disk space used by the database"
 
-    pg_stat_statements:
-      query: "SELECT t2.rolname, t3.datname, queryid, calls, total_time / 1000 as total_time_seconds, min_time / 1000 as min_time_seconds, max_time / 1000 as max_time_seconds, mean_time / 1000 as mean_time_seconds, stddev_time / 1000 as stddev_time_seconds, rows, shared_blks_hit, shared_blks_read, shared_blks_dirtied, shared_blks_written, local_blks_hit, local_blks_read, local_blks_dirtied, local_blks_written, temp_blks_read, temp_blks_written, blk_read_time / 1000 as blk_read_time_seconds, blk_write_time / 1000 as blk_write_time_seconds FROM pg_stat_statements t1 join pg_roles t2 on (t1.userid=t2.oid) join pg_database t3 on (t1.dbid=t3.oid)"
-      master: true
-      metrics:
-        - rolname:
-            usage: "LABEL"
-            description: "Name of user"
-        - datname:
-            usage: "LABEL"
-            description: "Name of database"
-        - queryid:
-            usage: "LABEL"
-            description: "Query ID"
-        - calls:
-            usage: "COUNTER"
-            description: "Number of times executed"
-        - total_time_seconds:
-            usage: "COUNTER"
-            description: "Total time spent in the statement, in milliseconds"
-        - min_time_seconds:
-            usage: "GAUGE"
-            description: "Minimum time spent in the statement, in milliseconds"
-        - max_time_seconds:
-            usage: "GAUGE"
-            description: "Maximum time spent in the statement, in milliseconds"
-        - mean_time_seconds:
-            usage: "GAUGE"
-            description: "Mean time spent in the statement, in milliseconds"
-        - stddev_time_seconds:
-            usage: "GAUGE"
-            description: "Population standard deviation of time spent in the statement, in milliseconds"
-        - rows:
-            usage: "COUNTER"
-            description: "Total number of rows retrieved or affected by the statement"
-        - shared_blks_hit:
-            usage: "COUNTER"
-            description: "Total number of shared block cache hits by the statement"
-        - shared_blks_read:
-            usage: "COUNTER"
-            description: "Total number of shared blocks read by the statement"
-        - shared_blks_dirtied:
-            usage: "COUNTER"
-            description: "Total number of shared blocks dirtied by the statement"
-        - shared_blks_written:
-            usage: "COUNTER"
-            description: "Total number of shared blocks written by the statement"
-        - local_blks_hit:
-            usage: "COUNTER"
-            description: "Total number of local block cache hits by the statement"
-        - local_blks_read:
-            usage: "COUNTER"
-            description: "Total number of local blocks read by the statement"
-        - local_blks_dirtied:
-            usage: "COUNTER"
-            description: "Total number of local blocks dirtied by the statement"
-        - local_blks_written:
-            usage: "COUNTER"
-            description: "Total number of local blocks written by the statement"
-        - temp_blks_read:
-            usage: "COUNTER"
-            description: "Total number of temp blocks read by the statement"
-        - temp_blks_written:
-            usage: "COUNTER"
-            description: "Total number of temp blocks written by the statement"
-        - blk_read_time_seconds:
-            usage: "COUNTER"
-            description: "Total time the statement spent reading blocks, in milliseconds (if track_io_timing is enabled, otherwise zero)"
-        - blk_write_time_seconds:
-            usage: "COUNTER"
-            description: "Total time the statement spent writing blocks, in milliseconds (if track_io_timing is enabled, otherwise zero)"
+    #WARNING: 
+    # This set of metrics can be very expensive on a busy server as every
+    # unique query executed will create an additional time series#
+
+    #pg_stat_statements:
+    # query: |
+    #   SELECT
+    #     pg_get_userbyid(userid) as user,
+    #     pg_database.datname,
+    #     pg_stat_statements.queryid,
+    #     pg_stat_statements.calls as calls_total,
+    #     pg_stat_statements.total_time / 1000.0 as seconds_total,
+    #     pg_stat_statements.rows as rows_total,
+    #     pg_stat_statements.blk_read_time / 1000.0 as block_read_seconds_total,
+    #     pg_stat_statements.blk_write_time / 1000.0 as block_write_seconds_total
+    #     FROM pg_stat_statements
+    #     JOIN pg_database
+    #       ON pg_database.oid = pg_stat_statements.dbid
+    #     WHERE
+    #       total_time > (
+    #         SELECT percentile_cont(0.1)
+    #           WITHIN GROUP (ORDER BY total_time)
+    #           FROM pg_stat_statements
+    #       )
+    #     ORDER BY seconds_total DESC
+    #     LIMIT 100
+    # metrics:
+    #   - user:
+    #       usage: "LABEL"
+    #       description: "The user who executed the statement"
+    #   - datname:
+    #       usage: "LABEL"
+    #       description: "The database in which the statement was executed"
+    #   - queryid:
+    #       usage: "LABEL"
+    #       description: "Internal hash code, computed from the statement's parse tree"
+    #   - calls_total:
+    #       usage: "COUNTER"
+    #       description: "Number of times executed"
+    #   - seconds_total:
+    #       usage: "COUNTER"
+    #       description: "Total time spent in the statement, in seconds"
+    #   - rows_total:
+    #       usage: "COUNTER"
+    #       description: "Total number of rows retrieved or affected by the statement"
+    #   - block_read_seconds_total:
+    #       usage: "COUNTER"
+    #       description: "Total time the statement spent reading blocks, in seconds"
+    #   - block_write_seconds_total:
+    #       usage: "COUNTER"
+    #       description: "Total time the statement spent writing blocks, in seconds"
 
     compass_director_tenants_total:
       query: "SELECT COUNT(ID) as quantity FROM business_tenant_mappings;"