added postgres_active_query_count.sql

sql/postgres_active_query_count.sql

@@ -0,0 +1,25 @@
+--
+--  Author: Hari Sekhon
+--  Date: 2020-08-05 15:33:36 +0100 (Wed, 05 Aug 2020)
+--
+--  vim:ts=2:sts=2:sw=2:et:filetype=sql
+--
+--  https://github.com/harisekhon/bash-tools
+--
+--  License: see accompanying Hari Sekhon LICENSE file
+--
+--  If you're using my code you're welcome to connect with me on LinkedIn and optionally send me feedback to help steer this or other code I publish
+--
+--  https://www.linkedin.com/in/harisekhon
+--
+
+-- PostgreSQL number of active queries
+--
+-- should be <= CPU Cores, otherwise upgrade/scale
+
+SELECT
+  COUNT(*) as active_query_count
+FROM
+  pg_stat_activity
+WHERE
+  state='active';