From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tender Wang <tndrwang@gmail.com>
cc: Dean Rasheed <dean.a.rasheed@gmail.com>,
        Duncan Sands <duncan.sands@deepbluecap.com>,
        pgsql-bugs@lists.postgresql.org
Subject: Re: Attribute of type record has wrong type error with MERGE ... WHEN
 NOT MATCHED BY SOURCE THEN DELETE
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Comments: In-reply-to Tender Wang <tndrwang@gmail.com>
	message dated "Mon, 10 Mar 2025 21:46:36 +0800"
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Date: Mon, 10 Mar 2025 11:00:46 -0400
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Tender Wang <tndrwang@gmail.com> writes:
> When the query has NOT MATCHED BY SOURCE, commit d7d297f84 add "src IS NOT
> NULL" join condition.
> In this case, the src is view(e.g. subquery), so in makeWholeRowVar(), it
> will call below code:
> result = makeVar(varno,
>                       InvalidAttrNumber,
>                       RECORDOID,
>                       -1,
>                       InvalidOid,
>                       varlevelsup);

> the vartype is RECORDOID, but te reltype of src is not RECORDOID, so
> $SUBJECT error reports.

Hmm.  I tried adjusting the example to make _country_or_region
be a materialized view or plain table instead of a view, and
those cases did not fail.  I wonder why the difference...

> I add the below codes to makeWholeRowVar() default branch:
> if (rte->relkind == RELKIND_VIEW)
>         toid = get_rel_type_id(rte->relid);
> else
>         toid = RECORDOID;
> It can work.

I'm quite uncomfortable with the idea of changing makeWholeRowVar()
itself in this way --- the potential blast radius from that seems
rather large.  A localized fix in transform_MERGE_to_join() might
be a wiser answer.

			regards, tom lane