From 3f19640715fcec26a24c04753dad5a5be51b3d8c Mon Sep 17 00:00:00 2001
From: Ibrar Ahmed <ibrar.ahmad@gmail.com>
Date: Tue, 2 Feb 2021 17:55:31 +0000
Subject: [PATCH] PG-172: Exponential histogram for time buckets.

---
 pg_stat_monitor--1.0.sql | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/pg_stat_monitor--1.0.sql b/pg_stat_monitor--1.0.sql
index 601009f..5b663db 100644
--- a/pg_stat_monitor--1.0.sql
+++ b/pg_stat_monitor--1.0.sql
@@ -177,6 +177,19 @@ SELECT
 $$
 LANGUAGE SQL PARALLEL SAFE;
 
+CREATE OR REPLACE FUNCTION histogram(_bucket int, _quryid text)
+RETURNS SETOF RECORD AS $$
+DECLARE
+ rec record;
+BEGIN
+for rec in
+        with stat as (select queryid, bucket, unnest(range()) as range, unnest(resp_calls)::int freq from pg_stat_monitor) select range, freq, repeat('■', (freq::float / max(freq) over() * 30)::int) as bar from stat where queryid = _quryid and bucket = _bucket
+loop
+return next rec;
+end loop;
+END
+$$ language plpgsql;
+
 GRANT SELECT ON pg_stat_monitor_settings TO PUBLIC;
 -- Don't want this to be available to non-superusers.
 REVOKE ALL ON FUNCTION pg_stat_monitor_reset() FROM PUBLIC;