From: Tom Lane <tgl@sss.pgh.pa.us>
To: Giovani Garcia <giovani.garcia@protonmail.com>
cc: "pgsql-interfaces@lists.postgresql.org"
 <pgsql-interfaces@lists.postgresql.org>
Subject: Re: Doubt regarding query parameter metadata
In-reply-to: 
 <eCpNID63M_eEUgOvB_39vy2LH_FaR9YS3hoUp7fYHbsKOQp9OzOfGglSQV3Cs50ajXJK3DBpZ-fma6qCawNyfX2Py3jnP7IOhr4FTUcbGBk=@protonmail.com>
References: 
 <eCpNID63M_eEUgOvB_39vy2LH_FaR9YS3hoUp7fYHbsKOQp9OzOfGglSQV3Cs50ajXJK3DBpZ-fma6qCawNyfX2Py3jnP7IOhr4FTUcbGBk=@protonmail.com>
Comments: In-reply-to Giovani Garcia <giovani.garcia@protonmail.com>
	message dated "Thu, 01 Apr 2021 03:33:40 -0000"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <3396839.1617286460.1@sss.pgh.pa.us>
Content-Transfer-Encoding: quoted-printable
Date: Thu, 01 Apr 2021 10:14:20 -0400
Message-ID: <3396840.1617286460@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/3396840.1617286460%40sss.pgh.pa.us>
Precedence: bulk

Giovani Garcia <giovani.garcia@protonmail.com> writes:
> The issue I'm finding is that the Oid returned for a VARCHAR column is T=
EXTOID (25) instead of VARCHAROID (1043).

This isn't hugely surprising in general.  varchar has no operations
of its own; PG treats it as sort of a domain over text.  So if you
do anything at all to a varchar column, it'd be quite likely for
the column to be implicitly coerced to text within the query.

> Now, when I run the following program (simplified for brevity),

> "SELECT key FROM oid_test WHERE value =3D $1",

Is that the *exact* query you're issuing?  I don't see anything
in that that would cause a coercion, but maybe you left out some
relevant detail.

			regards, tom lane