Message-ID: <41f5c07b-cb7b-428b-b9db-9e9db8c9238b@oss.nttdata.com>
Date: Thu, 12 Jun 2025 23:41:13 +0900
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Subject: Re: pg_dump --with-* options
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To: Peter Eisentraut <peter@eisentraut.org>,
 Nathan Bossart <nathandbossart@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>, pgsql@j-davis.com
References: <7cc52488-f876-4ad3-affd-6e4b0ef0cb09@eisentraut.org>
 <aEMLzPQtjRbj2R7X@nathan>
 <17f63ecf-679c-4337-817f-908bb159701f@eisentraut.org>
From: Fujii Masao <masao.fujii@oss.nttdata.com>
In-Reply-To: <17f63ecf-679c-4337-817f-908bb159701f@eisentraut.org>
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On 2025/06/12 22:47, Peter Eisentraut wrote:
> On 06.06.25 17:39, Nathan Bossart wrote:
>> On Fri, Jun 06, 2025 at 09:14:32AM +0200, Peter Eisentraut wrote:
>>> We have
>>>
>>> =C2=A0=C2=A0 -a, --data-only=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 dump only =
the data, not the schema or statistics
>>> =C2=A0=C2=A0 --no-data=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0 do not dump data
>>> =C2=A0=C2=A0 --with-data=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0 dump the data=C2=A0 # this one is new
>>>
>>> (and there is also --section=3Ddata), and then three analogous option=
s for
>>> "schema" and "statistics".
>>>
>>> What is the purpose of the --with-data option?=C2=A0 Dumping the data=
 is the
>>> default.=C2=A0 Is this to override an earlier --no-data option?
>>
>> I believe the idea is that these will allow folks to be explicit about=
 what
>> they want instead of needing to understand the defaults for every
>> component.
>=20
> I get that idea, but we really need some more documentation for this, I=
 think.=C2=A0 So far I could only guess how this is supposed to be used, =
and I also happened to guess wrong.
>=20
> My initial guess was that --with-data can override --no-data.=C2=A0 Tha=
t would have been pretty standard "last option wins" behavior.=C2=A0 But =
pg_dump rejects that.=C2=A0 Personally, I think that is kind of wrong.
>=20
> But you can use --with-data to override, say, --schema-only.=C2=A0 That=
 also seems kind of wrong to me, but anyway.

While testing pg_dump --with-* in relation to bug #18952 [1],
I also ran into this behavior. It was surprising,
as I expected pg_dump to reject that combination of options.
The current behavior seems confusing.

Regards,

[1] https://postgr.es/m/18952-be40a620f8b1e755@postgresql.org

--=20
Fujii Masao
NTT DATA Japan Corporation