From: | Michael Paquier <michael(at)paquier(dot)xyz> |
---|---|
To: | James Salsman <jsalsman(at)gmail(dot)com> |
Cc: | pgsql-docs(at)lists(dot)postgresql(dot)org |
Subject: | Re: monitoring-stats.html is too impenetrable |
Date: | 2019-12-06 03:04:45 |
Message-ID: | 20191206030445.GI121835@paquier.xyz |
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Thread: | |
Lists: | pgsql-docs |
On Wed, Dec 04, 2019 at 03:29:55AM -0800, James Salsman wrote:
> Thank you for your thoughtful reply. This might be much easier:
>
> How about adding another example to
> https://www.postgresql.org/docs/11/planner-stats.html ?
Not sure I see the parallel here. This page talks about planner
statistics, and yours about being able to find missing indexes because
of incorrect stats.
> SELECT relname, seq_scan-idx_scan AS too_much_seq,
> case when seq_scan-idx_scan>0 THEN 'Missing Index?' ELSE 'OK' END,
> pg_relation_size(relid::regclass) AS rel_size, seq_scan, idx_scan
> FROM pg_stat_all_tables
> WHERE schemaname='public' AND pg_relation_size(relid::regclass)>80000
> ORDER BY too_much_seq DESC;
Again. this is a bit more complex than that.
--
Michael
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