From: Tom Lane <tgl@sss.pgh.pa.us>
To: Daniele Varrazzo <daniele.varrazzo@gmail.com>
cc: pgsql-bugs <pgsql-bugs@postgresql.org>
Subject: Re: Types pollution with unknown oids and server-side parameters
 binding
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Comments: In-reply-to Daniele Varrazzo <daniele.varrazzo@gmail.com>
	message dated "Tue, 03 May 2022 21:10:20 +0200"
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Date: Tue, 03 May 2022 15:55:22 -0400
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Daniele Varrazzo <daniele.varrazzo@gmail.com> writes:
> A problem shown in https://github.com/psycopg/psycopg/discussions/289

> In the query:
>     UPDATE test289 SET num =3D $1, name =3D $2, ts =3D $3 WHERE ts::date=
 =3D $3::date

> passing a string with unknown oid as param $3 results in the column ts
> receiving only the date part. Looks like the cast needed on the param
> in the WHERE gets propagated to the other occurrences of the same
> parameter.

I think it's operating exactly as designed.  The parameter can only
have one type, and the cast is telling it to assume that that type
is "date".

> I see why it happens... I don't think it's the right behaviour though.

What do you think ought to happen?  The same parameter somehow having
different types in different places?

			regards, tom lane