Horton

Re: On disable_cost

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>, Alena Rybakina <a.rybakina@postgrespro.ru>, Laurenz Albe <laurenz.albe@cybertec.at>, Heikki Linnakangas <hlinnaka@iki.fi>, Peter Geoghegan <pg@bowt.ie>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-10-05T23:26:14Z
Lists: pgsql-hackers 
On Sun, 6 Oct 2024 at 08:35, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> BTW, getting off the question of EXPLAIN output for a moment,
> I don't understand why disable_cost is still a thing.  The
> one remaining usage seems trivial to replace, as attached.

I didn't notice that any of these remained. I agree we should get rid
of it. The patch looks fine to me.

David

Commits

  1. Doc: add detail about EXPLAIN's "Disabled" property

  2. Adjust EXPLAIN's output for disabled nodes

  3. Fix order of parameters in a cost_sort call

  4. Show number of disabled nodes in EXPLAIN ANALYZE output.

  5. Treat number of disabled nodes in a path as a separate cost metric.

  6. Remove grotty use of disable_cost for TID scan plans.