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From: Junwang Zhao <zhjwpku@gmail.com>
Date: Sun, 26 Apr 2026 23:10:24 +0800
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Subject: Re: [PATCH] Resolve unknown-type literals in GRAPH_TABLE COLUMNS
To: SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
	Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
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Hi SATYANARAYANA,

On Sun, Apr 26, 2026 at 3:53=E2=80=AFAM SATYANARAYANA NARLAPURAM
<satyanarlapuram@gmail.com> wrote:
>
> Hi hackers,
>
> transformRangeGraphTable() calls transformExpr() and
> assign_list_collations() for COLUMNS expressions but missed calling
> resolveTargetListUnknowns(). As a result, literals such as 'val1'
> in a COLUMNS clause retained type "unknown", causing failures with
> ORDER BY, UNION, and output conversions.
>
> Fix by calling resolveTargetListUnknowns() on the columns target
> list right after assign_list_collations(), similar to SELECT target lists=
 in
> transformSelectStmt().
>
> Attached a patch to fix this, which also includes test cases to reproduce=
.

I can reproduce this and the patch fixes it.

One question: why is resolveTargetListUnknowns called after
assign_list_collations?

I'm asking because in transformSelectStmt, resolveTargetListUnknowns
is invoked before assign_query_collations. It might not matter, but keeping
the order consistent would be good for readers.

>
>
> Thanks,
> Satya
>
>


--=20
Regards
Junwang Zhao