Re: BUG #18764: server closed the connection unexpectedly

Thanks for the quick fix and detailed explanation.

Jason
---- Replied Message ----
| From | David Rowley<dgrowleyml(at)gmail(dot)com> |
| Date | 1/10/2025 09:36 |
| To | Richard Guo<guofenglinux(at)gmail(dot)com> |
| Cc | Tom Lane<tgl(at)sss(dot)pgh(dot)pa(dot)us>,
<dqetool(at)126(dot)com>,
<pgsql-bugs(at)lists(dot)postgresql(dot)org> |
| Subject | Re: BUG #18764: server closed the connection unexpectedly |
On Thu, 9 Jan 2025 at 20:38, Richard Guo <guofenglinux(at)gmail(dot)com> wrote:

On Thu, Jan 9, 2025 at 12:44 PM David Rowley <dgrowleyml(at)gmail(dot)com> wrote:
Can't you just look up the setop's type from op->colTypes instead of
looking the type up via the sortop? i.e. the attached?

Yeah, right. Using SetOperationStmt.colTypes is more convenient here.

I pushed a revised patch. I removed the check for the sortop. I first
also thought I'd overlooked that, but it turned out that's fine as it
was as standard_qp_callback() handles checking for un-sortable
SortGroupClauses.

Jason, you can expect a fix for this in 17.3. In the meantime, you
could add an explicit cast to numeric in the subquery, e.g:

SELECT c2 AS ca2, c2 AS ca3
FROM t0
UNION
SELECT DISTINCT ca8 AS ca5, ca7::numeric AS ca6
FROM (
SELECT c1 AS ca7, c2 AS ca8 FROM t0
) AS ta1 JOIN (
SELECT c1 AS ca10, c1 AS ca11
FROM t0
) AS ta2 ON TRUE;

Thanks for the report.

David