Date: Thu, 5 Nov 2020 11:20:30 -0600
From: Justin Pryzby <pryzby@telsasoft.com>
To: Andrey Borodin <x4mmm@yandex-team.ru>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Tom Lane <tgl@sss.pgh.pa.us>,
	Darafei =?utf-8?Q?Kom=D1=8Fpa?= Praliaskouski <me@komzpa.net>,
	Pavel Borisov <pashkin.elfe@gmail.com>,
	Thomas Munro <thomas.munro@gmail.com>,
	Michael Paquier <michael@paquier.xyz>,
	Alexander Korotkov <a.korotkov@postgrespro.ru>,
	pgsql-hackers@postgresql.org
Subject: Re: Yet another fast GiST build
Message-ID: <20201105172030.GE22691@telsasoft.com>
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On Thu, Nov 05, 2020 at 10:11:52PM +0500, Andrey Borodin wrote:
> To test that functions are actually called for sorting build we should support directive sorting build like "CREATE INDEX ON A USING GIST(B) WITH(sorting=surely,and fail if not)".

Maybe you could add a DEBUG1 message for that, and include that in regression
tests, which would then fail if sorting wasn't used.

Maybe you'd need to make it consistent by setting GUCs like work_mem /
max_parallel_maintenance_workers / ??

Similar to this

postgres=# SET client_min_messages =debug;
postgres=# CREATE INDEX ON A USING GIST(i) WITH(buffering=off);
DEBUG:  building index "a_i_idx2" on table "a" serially
CREATE INDEX

> If we have unconditional sorting build and unconditional buffered build we can check opclasses code better.
> The problem is current reloption is called "buffering". It would be strange if we gave this enum possible value like "not buffering, but very much like buffering, just another way".
> How do you think, is it ok to add reloption "buffering=sorting" to enhance tests?
> 
> Best regards, Andrey Borodin.