Horton

Re: On disable_cost

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Laurenz Albe <laurenz.albe@cybertec.at>, Heikki Linnakangas <hlinnaka@iki.fi>, Peter Geoghegan <pg@bowt.ie>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-10-05T16:05:25Z
Lists: pgsql-hackers 
David Rowley <dgrowleyml@gmail.com> writes:
> I'd encourage anyone else on the sidelines who has an opinion on how
> to display the disabled-ness of a plan node in EXPLAIN to speak up
> now, even if it's just a +1 to something someone has already written.
> It would be nice to see what more people think.

FWIW, I do not like the current display one bit.

I think "Disabled: true" on only the nodes that are themselves disabled
would be a very substantial readability improvement.

			regards, tom lane

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.