--
--  Author: Hari Sekhon
--  Date: 2020-08-05 15:28:12 +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 Indexes Cache-hit Ratio
--
-- should be closer to 1, eg. 0.99

SELECT
  SUM(idx_blks_read) AS idx_read,
  SUM(idx_blks_hit)  AS idx_hit,
  (SUM(idx_blks_hit) - SUM(idx_blks_read)) /
					SUM(idx_blks_hit)
							AS ratio
FROM
  pg_statio_user_indexes
ORDER BY
  ratio DESC;