Date: Wed, 25 Jun 2025 09:48:12 -0500
From: Nathan Bossart <nathandbossart@gmail.com>
To: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Jeff Davis <pgsql@j-davis.com>,
	Peter Eisentraut <peter@eisentraut.org>,
	pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: pg_dump --with-* options
Message-ID: <aFwMLD7S8tbsafc3@nathan>
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On Wed, Jun 25, 2025 at 08:18:28AM +0900, Fujii Masao wrote:
> For pg_dump and pg_dumpall, I agree with Jeff's idea in [1],
> but if the statistics is skipped by default, I don't think
> we need a --no-statistics option. So, here's how I think
> the options should work:
> 
>     * Keep: --schema-only, --data-only, --statistics-only, --no-schema, --no-data, -and -statistics
>     * Remove: --no-statistics, --with-schema, and --with-data
>     * Combinations:
>         Schema + Data + Stats     : --statistics
>         Schema + Data             : (default)
>         Schema + Stats            : --no-data --statistics
>         Data + Stats              : --no-schema --statistics
>         Schema only               : --schema-only   (or --no-data)
>         Data only                 : --data-only     (or --no-schema)
>         Stats only                : --statistics-only (or --no-schema --no-data --statistics)

I believe this is equivalent to the second option I proposed upthread [0].
Jeff proposed a variation of this option that keeps --no-statistics around
so that we could more easily change the default for stats down the road
[1].

> As I mentioned in [2], if we treat --statistics in the similar way to
> --sequence-data, i.e., allow --statistics to be used with --schema-only
> or --data-only, we could simplify further:
> 
>     * Keep: --schema-only, --data-only, --statistics-only, and --statistics
>     * Remove: --no-schema, --no-data, --no-statistics, --with-schema, and --with-data
>     * Combinations:
>         Schema + Data + Stats     : --statistics
>         Schema + Data             : (default)
>         Schema + Stats            : --schema-only --statistics
>         Data + Stats              : --data-only --statistics
>         Schema only               : --schema-only
>         Data only                 : --data-only
>         Stats only                : --statistics-only
> 
> Some may find this confusing due to mixing --statistics with --schema-only
> or --data-only, so I understand if there's hesitation.

Hm.  I didn't really intend for --sequence-data to set a precedent here.
That's mostly intended as a submode for --binary-upgrade.  Perhaps we
should consider removing it as a documented option and instead convert it
to --binary-upgrade=sequence-data or something.  In any case, allowing
"only" options to be used in conjunction with --statistics seems a little
confusing to me.  But I'm not strongly opposed to the idea.

> For pg_restore, I believe there's agreement to restore statistics
> by default if they exist in the archive. So:
> 
>     * Keep: --schema-only, --data-only, --statistics-only, --no-schema, --no-data, and --no-statistics
>     * Remove: --with-schema, --with-data, and --statistics
>     * Combinations:
>         Schema + Data + Stats     : (default)
>         Schema + Data             : --no-statistics
>         Schema + Stats            : --no-data
>         Data + Stats              : --no-schema
>         Schema only               : --schema-only   (or --no-data --no-statistics)
>         Data only                 : --data-only     (or --no-schema --no-statistics)
>         Stats only                : --statistics-only (or --no-schema --no-data)

+1

[0] https://postgr.es/m/aFLxvrh71VWqdL9A%40nathan
[1] https://postgr.es/m/031558c60e84362898922caa6a90587e7fdf2a57.camel%40j-davis.com

-- 
nathan